practice

Explanation

Obturation (obstruction, to close) of bile duct – it can be:

* Intrahepatic – blockage of intrahepatic bile ducts

* Extrahepatic – blockage of common bile duct (ductus choledochus).

Findings:

* malabsorption: bile salts do not enter the Small Intestine; no emulsification of fat.

*light coloured stool: due to lack of urobilin (which leads to lack of stercobilin).

*Jaundice (posthepatic, mechanic, obstructive): increased conjugated Bilirubin.

* Steatorrhea

The findings are specific for obstruction of bile duct and bile acid deficiency.

Explanation

Acidosis is the reduction in pH (increase in H⁺ concentration) below normal range. pH is less than 7.35; it is produced by:

·        Increase in partial pressure of CO₂ in the body.

·        Decrease in HCO₃^- concentration.

Alkalosis is the increase in pH (decrease in H⁺ concentration) above normal range. pH is greater than 7.45; it is produced by:

·        Decrease in partial pressure of CO₂ in the body.

·        Increase in HCO₃^- concentration.

Each of these two disorders has respiratory and non-respiratory forms. The non-respiratory form is divided into metabolic and excretory(non-gaseous).

·        Respiratory acidosis is the acidosis that is caused by alveolar hypoventilation e.g. airway obstruction due to bronchitis or lung diseases (pneumonia).

·        Respiratory alkalosis is caused by alveolar hyperventilation e.g. hypoxia in high altitude.

·        Non-respiratory:

-Metabolic acidosis is characterized by excess accumulation of organic acids such as lactic acid, ketoacids and uric acid formed by normal metabolism e.g. in Diabetes mellitus or extreme/prolonged exercise.

-Excretory/Non-gaseous acidosis may develop in impaired renal H⁺ excretion related to increased loss of bicarbonate in urine; diarrhea causes acidosis by the loss of bicarbonate with faeces.

-Excretory/Non-gaseous alkalosis: vomiting (loss of gastric acid), increased metabolism of lactate and citrate (turns into bicarbonate and water), long-term use of thiazides and loop diuretics.

      It is excretory/non-gaseous alkalosis because of the frequent vomiting.

Explanation

Idiosyncrasy and allergic reaction is as a result of organism’s increased sensitivity to the drugs. It’s a complication of pharmacological therapy (adverse reactions). 

 Idiosyncrasy is genetically conditioned perverse organism’s response to drugs (e.g. inefficiency, lack of enzymes participating in drug metabolism). Genetic deficiency of glucose 6-phosphate dehydrogenase (hereditary enzymopathy). This enzyme is needed for proper functioning of glutathione (an antioxidant) to prevent the oxidative effect of antimalarial drugs on the RBCs (erythrocytes).

Explanation

One of the laboratory tests for diabetes mellitus is the level of glycosylated hemoglobin. Glycosylated hemoglobin test (HbA_1C, glycohemoglobin) are proteins with glucose bound to them by nonenzymatic way. They precisely represent the extent of impairment of the carbohydrate metabolism and serve as the basic index of quality of compensation of diabetes mellitus. The level of HbA_1C is determined by the method of chromatography using special laboratory equipment. Level of HbA_1C shows an average blood concentration during the previous 2 - 3 months. Normal level of HbA_1C is 4 – 6%. [4 – 8 weeks (1-2months)]

Explanation

The inferior mesenteric artery arises from the anterior aspect of the abdominal aorta. The artery gives the branches as follows: left colic artery (arteria colica sinistra); sigmoid arteries (supplies sigmoid colon) and superior rectal artery (supplies the rectum). Left colic artery (sinister colic) ascends leftwards to supply the descending colon. On reaching the intestine, the artery gives the ascending and descending branches that anastomose with the middle colic artery and sigmoid artery.

Explanation

        Phenylin is an anticoagulant. It has actions similar to warfarin, but it is now rarely employed because of its higher incidence of severe adverse effects. The barbiturate (Phenobarbital) is a sedative or used to induce and maintain sleep. But today, they have been largely replaced by the benzodiazepines (diazepam, nitrazepam), primarily because barbiturates induce tolerance, drug-metabolizing enzymes and physical dependence and are associated with very severe withdrawal symptoms. Barbiturates induce the CYP450 system and therefore, may decrease the duration of action of drugs that are metabolized by these hepatic enzymes. Through this mechanism, Phenobarbital causes a decrease in anticoagulant activity as measured by the prothrombin time. Phenobarbital induce hepatic microsomal enzymes resulting in increased metabolism and decreased anticoagulant response of oral anticoagulants (e.g. Phenylin, warfarin).

Explanation

Two membranes divide the spiral canal of cochlea into 3 compartments – vestibular and basilar membrane. Along the basilar membrane are 20,000-30,000 tiny fibers called basilar fibers. Each fiber has different size and shape. Fibers near the oval window (base) are short and stiff (narrowest), while approaching towards helicotrema (apex), the basilar fibers gradually become longer and soft (widest). The motion of the basilar membrane is generally described as a travelling wave. The parameters of the membrane (stiffness, narrow, wide) at a given point along its length determine its characteristic frequency at which it is most sensitive to sound vibrations. High frequency sounds localize near the base of the cochlea (near the round and oval windows), while low frequency sounds localize near the apex (helicotrema); and the middle frequency sounds – middle part of helix.

Explanation

        Isoenzyme is any of several forms of an enzyme that all catalyze the same reaction but may differ in reaction rate, inhibition by various substances, electrophoretic mobility or immunologic properties. Examples of important enzymes with isoenzymic forms are:

·        Lactate dehydrogenase: LDH₁, LDH₂, LDH₃, LDH₄, LDH₅, (5 isoenzymic forms).

·        Creatine kinase (CK): CK-MM; CK-MB; CK-BB (3 isoenzymic forms)

Explanation

Explanation

A large number of components are required for translation (synthesis of a protein). These include all the amino acids that are found in the finished product, the mRNA to be translated, tRNA, functional ribosomes, energy sources and enzymes as well as protein factors needed for initiation, elongation and termination of the polypeptide chain. In eukaryotic cells, the ribosomes are either “free” in the cytosol or are in close association with the endoplasmic reticulum (which is then known as the “rough” endoplasmic reticulum or RER). The RER – associated ribosomes are responsible for synthesizing proteins that are to be exported from the cell as well as those that are destined to become integrated into plasma, endoplasmic reticulum or golgi membranes or incorporated into lysosomes.

Explanation

The dog is conditioned to salivate at the sight of food and flash of light – that is a conditioned reflex that requires learning, memory and recall of previous experience (likewise the student, taking notes requires learning, memory and recall of previous experience). The established conditioned reflexes can be inhibited: externally and internally.

External inhibition: disturbing factors like a stranger, sudden noise (the students talking) or a strong smell can abolish the conditioned reflex and inhibit salivary secretion. This extra stimulus evokes the animal’s curiosity  and distracts the attention. Internal inhibition can be:

*Extinction of conditioned reflex: failure to reinforce the conditioned reflex by unconditioned stimulus.

*Differential: alteration of conditioned stimulus.

Explanation

Glucocorticoids (prednisolone) stimulate gluconeogenesis. As a result, blood sugar rises, muscle protein is catabolized and insulin secretion is stimulated. Corticosteroids cause increased gluconeogenesis, increased lipolysis, CNS effects - at times including euphoria, maintenance of cardiovascular function by potentiation of norepinephrine. Gluconeogenesis uses the reversible reactions from glycolysis and 4 distinct reactions that circumvent the ones from glycolysis that are irreversible. These reactions are catalyzed by pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose-1, 6-bisphosphatase and glucose-6-phosphatase. Glucagon, epinephrine and glucocorticoids stimulate all these enzymes (excluding pyruvate carboxylase).

Explanation

A large number of components are required for translation (synthesis of a protein). These include all the amino acids that are found in the finished product, the mRNA to be translated, tRNA, functional ribosomes, energy sources and enzymes as well as protein factors needed for initiation, elongation and termination of the polypeptide chain. In eukaryotic cells, the ribosomes are either “free” in the cytosol or are in close association with the endoplasmic reticulum (which is then known as the “rough” endoplasmic reticulum or RER). The RER – associated ribosomes are responsible for synthesizing proteins that are to be exported from the cell as well as those that are destined to become integrated into plasma, endoplasmic reticulum or golgi membranes or incorporated into lysosomes.

   The labeled amino acids will be accumulated close to the ribosomes and rough endoplasmic reticulum (RER).

Explanation

Idiosyncrasy and allergic reaction is as a result of organism’s increased sensitivity to the drugs. It’s a complication of pharmacological therapy (adverse reactions). Tolerance and Tachyphylaxis are effects of repeated doses.

* Idiosyncrasy is genetically conditioned perverse organism’s response to drugs (e.g. inefficiency, lack of enzymes participating in drug metabolism). Genetic deficiency of glucose 6-phosphate dehydrogenase (hereditary enzymopathy). This enzyme is needed for proper functioning of glutathione (an antioxidant) to prevent the oxidative effect of antimalarial drugs on the RBCs.

* Allergic reactions results from antibody production against some drugs.

* Tachyphylaxis is quick weakening of the effect, sometimes may occur after first drug introduction (usually connected with substrate exhaustion).

* Tolerance (habituation): is increasing of the effects in repeated doses resulting from decreasing of absorption, speed-up of the biotransformation or excretion, or decreasing of the receptors sensitivity.

Explanation

The walls of the tympanic cavity (6): tegmental wall, jugular wall, labyrinthine wall, membranous wall, carotid wall and mastoid wall. The mastoid wall (paries mastoideus) is the posterior wall related to the mastoid process of temporal bone. The opening on the wall – the aditus, to mastoid antrum leads to the greatest air cell called the mastoid antrum (antrum mastoideum) and further to smaller mastoid air cells.

Explanation

Innate or non-specific resistance consist of physical and chemical barriers such as skin, gastric acid, mucus or tears, saliva as well as cells and active mechanisms such as phagocytes, natural killer cells and the complement system. They defend an organism in non-specific form/manner, responding in the same fashion, regardless of what pathogen it is. Examples of physical barriers:

·        Skin: surface is made up of dead skin cells rich in keratin, which impedes microorganisms from entering the body – mechanical barrier

·        Gastric acid is a powerful defense against invading bacteria.

·        Saliva and tears contain antibacterial enzymes such as lysozyme, which destroy the cellular walls of bacteria.

·        Mucus is another defense; coating the mucus membranes and contains IgA antibodies (a component of specific/adaptive immune system).

Explanation

     Stress activates the sympathoadrenal system and the hypothalamic-pituitary-adrenocortical (HPA) axis. Defense reactions involve catecholamine release, vagal withdrawal, cortisol secretion and activation of the rennin-angiotensin system. Catecholamine release is capable of increasing the arterial pressure. Sympathoadrenal system involves the sympathetic nervous system and the adrenal glands especially increased sympathetic activity that causes increased secretion of epinephrine by the adrenal medulla and norepinephrine by the postganglionic sympathetic nerve endings.

Explanation

Sickle cell hemoglobin (HbS) point mutation causes a single amino acid replacement in β chain of hemoglobin (substitution of glutamic acid with valine). Pathogenesis of sickle cell anemia: low O₂, high altitude or acidosis precipitates sickling – modified shape (deoxygenated HbS polymerizes) → anemia and vaso-occlusive disease. Clinical findings include: dizziness, general weakness, fatigue, “crew-cut” on skull X-ray due to marrow expansion from increased erythropoiesis (this is also seen in thalassemia)  etc. Sickle cells are crescent-shaped RBCs.

Explanation

Blood minute volume is the amount of blood pumped out by each ventricle in one minute. It is the product of stroke volume and heart rate. Normal value is 5L/ventricle/minute.

If blood minute volume is 5L/m; the volume pumped through the pulmonary vessels (lung vessels) per minute by the right ventricle equals 5L.

Explanation

       Starvation decreases protein synthesis because the substrates are not readily available. Decrease in protein synthesis decreases oncotic pressure and thereby increasing glomerular filtration. Net filtration pressure is the balance between hydrostatic pressure (glomerular capillary pressure) and oncotic pressure.

Net filtration pressure = Hydrostatic pressure – Oncotic pressure

Therefore, a decrease in oncotic pressure increases the filtration rate according to the degree of starvation which decreases protein synthesis.

Explanation

Explanation

Explanation

 The end product of the purine nucleotides catabolism in humans and other primates is uric acid (urate) which is excreted in urine. Allopurinol and febuxostat inhibits Xanthine oxidase (XO). Hypoxanthine and Xanthine which is more soluble is excreted in urine. Purine nucleotides (adenine and guanine).  AMP – Adenosine monophosphate; GMP – Guanosine monophosphate

Pyrimidine (thymine, Uracil, cytosine); catabolism of thymine and uracil gives urea, while catabolism of cytosine gives β-alanine.

Explanation

     Acute phase reactants are factors whose serum concentrations change significantly in response to inflammation produced by the liver in both acute and chronic inflammatory states. Notably induced by IL-6 e.g. C-reactive protein, hepcidin, serum amyloid A are all upregulated; while albumin and transferring are downregulated. C-reactive protein is an opsonin, it fixes complement and facilitates phagocytosis. It is measured  clinically as a sign of ongoing inflammation.

Explanation

        Thyroid hormone increases synthesis of β-adrenergic receptors for catecholamines. Catecholamines (epinephrine) exert their effect on the heart by binding to β₁-adrenoreceptors, which in turn increases the heart rate. Increase in heart rate shows a decrease in R-R interval on the ECG. This can lead to clinical manifestations such as systemic hypertension and high output heart failure.

Explanation

     Paraprotein, myeloma protein, M protein or spike protein is an abnormal immunoglobulin (Ig) fragment or immunoglobulin (Ig) light chain that is produced in excess by an abnormal clonal proliferation of plasma cells, typically in multiple myeloma. Monoclonal free light chains in the serum or urine are called bence jones (BJ) proteins.

Bence jones (BJ) protein: free kappa (κ) or lambda (λ) light chains that are excreted in urine associated with plasma cell malignancies (myeloma) and Waldenstrὄm macroglobulinemia. In myeloma, urinalysis for BJ protein is positive in 60-80% of cases.

Myeloma/Plasmocytoma/Multiple Myeloma

Explanation

Hyperemia or active hyperemia or arterial hyperemia is the term used for the increased volume of blood in the arterial or arteriolar vessels. It is caused by an increased supply of blood from arterial system. The affected tissue or organ is pink or red in appearance (erythema) and warm to the touch.

     Venous or passive hyperemia also known as congestion; the affected tissue or organ is cold to the touch.

Explanation

     Etiotropic drug deals directly with the etiological factor (diphtheria toxin). Antidiphtheric antitoxic serum neutralizes the toxin of diphtheria and is employed both as a curative and as a prophylactic agent. Diphtheric anatoxin (diphtheria toxoid) is the diphtheria toxin that has been weakened until it is no longer toxic but is strong enough to induce the formation of antibodies and immunity to the disease.

Explanation

Parathyroid hormone: secreted by chief cells of parathyroid gland. Effects include:

↑bone resorption of Ca²⁺ and PO₄^3- → ↑their plasma levels

↑kidney reabsorption of Ca²⁺ in distal convoluted tubule → ↑ Ca²⁺ plasma level

↓reabsorption of PO₄^3- in proximal convoluted tubule → ↓ PO₄^3- plasma levels

↑Calcitriol (vit D₃) production by stimulating kidney 1α-hydroxylase in proximal convoluted tubule. It increases Ca²⁺ and PO₄^3- absorption in the intestine.

In general, parathyroid hormone ↑ Ca²⁺ plasma level but ↓ PO₄^3- plasma levels. Abnormal synthesis (↑synthesis) of parathyroid hormone can lead to hypercalcemia and hypophosphatemia.

Explanation

Explanation

There is a certain correlation between age of an individual and thymus activity. In neonates, it already appears to have a considerable mass of 13.3g on the average. Most intensive growth occurs during first 3 years of life, when the gland doubles in size. Having reached the maximum weight (about 26 – 30g), the thymus retains it until 20years of life. After 20 years of age, the thymus parenchyma experiences gradual involution and is substituted with fat tissue. After 50 years of age, the fat constitutes 90% of gland mass.

Explanation

Obturation (obstruction, to close) of bile duct – it can be:

* Intrahepatic – blockage of intrahepatic bile ducts

* Extrahepatic – blockage of common bile duct (ductus choledochus).

Findings:

* malabsorption: bile salts do not enter the Small Intestine; no emulsification of fat.

*light coloured stool: due to lack of urobilin (which leads to lack of stercobilin).

*Jaundice (posthepatic, mechanic, obstructive): increased conjugated Bilirubin.

* Steatorrhea

The findings are specific for obstruction of bile duct and bile acid deficiency.

Explanation

Staphylococcus aureus is a gram positive cocci that appear in clusters. It causes:

·        Inflammatory disease  like skin infections, organ abscesses

·        Toxin mediated disease like the toxic shock syndrome (TSST-1)

·        MRSA (methicillin-resistant Staphylococcus aureus) infection.

Staphylococcus aureus is a β-hemolytic bacteria i.e. they form a clear zone of hemolysis on blood agar. They are catalase and coagulase (plasmocoagulase) positive.

Explanation

The end product of the purine nucleotides catabolism in humans and other primates is uric acid (urate) which is excreted in urine and can also cause kidney stones (renal calculi). Allopurinol and febuxostat inhibits Xanthine oxidase (XO). Hypoxanthine and Xanthine which is more soluble is excreted in urine. Purine nucleotides (adenine and guanine).  AMP – Adenosine monophosphate; GMP – Guanosine monophosphate

Pyrimidine (thymine, Uracil, cytosine); catabolism of thymine and uracil gives urea, while catabolism of cytosine gives β-alanine.

Explanation

       There are two types of fungi: yeasts and molds. Yeasts grow as single cells that reproduce by asexual budding (gemmating). Molds grow as long filaments (hyphae) and form a mat (mycelium). Candida albicans is an oval yeast with a single bud. It is part of the normal flora of mouth (oral cavity), mucous membranes of upper respiratory, gastrointestinal and female genital tracts. In tissues it may appear as yeast or as pseudohyphae. Pseudohyphae are elongated yeasts (elongated chains) that visually resemble hyphae but are not true hyphae. Candida albicans causes thrush, vaginitis, esophagitis and chronic mucocutaneous candidiasis.

Explanation

Cushing Syndrome: Etiology

*INCREASE Cortisol due to a variety of causes (Glucocorticoids).

*Exogenous corticosteroids:  result in DECREASE ACTH (MCC).

*Primary adrenal adenoma, hyperplasia or carcinoma (Cushing’s Syndrome).                                     *ACTH-secreting pituitary adenoma (Cushing Disease).

Findings: Hypertension, Weight Gain, Moon Facies, Truncal Obesity, Buffalo Hump, Skin Changes (thinning striae), Osteoporosis, Hyperglycemia (Insulin resistance), Amenorrhea, Immunosuppression.

Explanation

           There are two medically important genera of gram positive cocci: Staphylococcus and Streptococcus. They are nonmotile and do not form spores. Microscopically, staphylococci appear in grape-like clusters and produce catalase (i.e. catalase positive), whereas streptococci are in chains and do not produce catalase (i.e. catalase negative). One of the most important characteristics for identification of streptococci is the type of hemolysis they manifest (alpha-hemolytic and beta hemolytic). Alpha-hemolytic (α-hemolytic) streptococci form a green zone around their colonies as a result of incomplete lysis of RBCs in the agar. Beta-hemolytic (β-hemolytic) streptococci form a clear zone around their colonies because complete lysis of the RBCs occurs. Β-hemolysis is due to the production of enzymes (hemolysins) called streptolysin O and streptolysin S. Some streptococci are non-hemolytic (gamma-hemolysis).

Explanation

       Iron requires an acidic medium in stomach to be absorbed. Iron is needed in heme synthesis (hemoglobin). A deficiency of iron will produce marked hypochromia (Hb – 70g/L; Normal: 120-140 female; 135-165 male) and decreased colour index (normal 0.85 – 1.05).

Megalocytes and macrocytes are usually caused by Vitamin B₁₂ and Folic acid deficiencies which often produce normochromic/hypochromic anemia because they are not really involved in hemoglobin synthesis. The resection of the pyloric part of stomach can reduce the gastric acid level thereby reducing iron absorption.

Explanation

Hippuric acid has been a major human metabolite for years. However, there is no well-known documented health benefit associated with it except for excretion of environmental-toxic exposures of aromatic compounds such as toluene or from dietary protein degradation and resynthesis by intestinal microflora metabolism of quinic acid via the shikimate pathway. Thus hippuric acid can appear in humans as an excretory product from natural or unnatural sources. It has been believed over the years that the major source of urinary hippuric acid levels in humans has come from environmental toxic solvent exposures.

Explanation

There are two medically important Bacillus species: Bacillus anthracis and Bacillus cereus. Bacillus anthracis causes anthrax. Human disease occurs in 3 main forms: cutaneous, pulmonary (inhalation) and gastrointestinal. Humans are most often infected cutaneously at the time of trauma to the skin, which allows the spores on animal products such as hides, bristles and wool to enter. Spores can also be inhaled or when contaminated meat is ingested. After being inhaled, the organism moves rapidly to the mediastinal lymph nodes and causes hemorrhagic mediastinitis. Pathogenesis is based on the production of two exotoxins  (Anthrax toxin) – edema factor and lethal factor. Hemorrhagic mediastinitis, septic shock hemorrhagic meningitis and death are severe life-threatening complications. In fatal cases, the organism may affect the spleen, liver, intestines, kidneys, adrenal glands and meninges.

Explanation

Anthracosis also known as Coal workers’ pneumoconiosis or black lung disease; it is caused by lung exposure to coal dust. It is common in coal miners and others who work with coal. Inhaled coal dust progressively builds up in the lungs and is unable to be removed by the body; this leads to inflammation, fibrosis and in worse cases necrosis.

Explanation

           Mycobacteria are aerobic, acid fast bacilli (rods). They are neither gram +ve nor  gram -ve i.e. they are stained poorly by the dyes used in gram stain. They are virtually the only bacteria that are acid-fast (one exception is Nocardia asteroids, the major cause of Nocardiosis, which is also acid-fast). The term  “acid-fast” refers to an organism’s ability to retain the carbolfuchsin stain despite subsequent treatment with an ethanol-hydrochloric acid mixture. The high lipid content (approx. 60%) of their cell wall makes Mycobacteria acid-fast.The major pathogens are Mycobacterium tuberculosis, the cause of tuberculosis and Myobacterium lepra, the cause of leprosy. M. tuberculosis grows slowly. Its cell wall contains long chain (C₇₈-C₉₀) fatty acids called mycolic acids, which contribute to the organism’s acid-fastness. Ziehl-Neelsen stain is also known as acid-fast stain.

Explanation

        The clinical manifestations are secondary sexual characteristics of an adult male.

Early in male development, mesenchyme separating the seminiferous cords gives rise to leydig (interstitial) cells that produce testosterone to stimulate development of the indifferent primordium into a testis. Leydig cells are large, polygonal, eosinophilic cells that typically contain lipid droplets. Leydig cells differentiate and secrete testosterone during early fetal life. Secretion of testosterone is required during embryonic development, sexual maturation and reproductive function:

·        In the embryo, secretion of testosterone and other androgens is essential for the normal development of the gonads in the male fetus.

·        At puberty, secretion of testosterone is responsible for the initiation of sperm production, accessory sex gland secretion and development of secondary sex characteristics.

·        In the adult, secretion of testosterone is essential for the maintenance of spermatogenesis and of secondary sex characteristics, genital excurrent ducts and accessory sex glands.

 The manifestation of these characteristics in a 10year old boy is as a result of increased secretion of the male sex hormone – Testosterone.

Explanation

Diffuse cardiosclerosis

Diffuse – multiple whitish layers of connective tissue

Cardiosclerosis – Atherosclerotic calcified plaques

Explanation

RNA dependent DNA polymerase

     DNA polymerase – synthesizes DNA

     RNA dependent – from mRNA (on the matrix of virus mRNA)

       Human immunodeficiency virus (HIV): diploid genome (2 molecules of RNA). The 3 structural genes(i.e. proteins coded for by the genes) are:

·        env (gp 120 and gp 41): formed from cleavage of gp 160 to form envelope glycoproteins. gp 120 is for attachment to host CD4+ T cell. gp 41 is for fusion and entry.

·        Gag (p24): capsid protein

·        pol: reverse transcriptase, aspartate protease, integrase.

ELISA/Western blot (immunoblot) tests look for antibodies to the viral proteins listed above.

Reverse transcriptase synthesizes dsDNA (ds-double stranded) from genomic RNA (mRNA); dsDNA integrates into host genome. Virus binds CD4 as well as a coreceptor, either CCR5 on macrophages (early infection) or CXCR4 on I cells (late infection).

·        Homozygous CCR5 mutation – immunity

·        Heterozygous CCR5 mutation – slower course.

Explanation

   Flexor digitorum superficialis (superficial finger flexor) arises by two heads – the humero-ulnar head and radial head from the corresponding bones. The spindle-shaped belly of the muscle divides into 4 long tendons, which pass under the flexor retinaculum and attach to the bases of the middle phalanges of the II through V digits. Prior to this, each tendon separates into two slips and forms a cleft, which gives passage to the tendon of the flexor digitorum profundus. The flexor digitorum profundus (profound/deep finger flexor) resides in the middle of the deep layer underneath the flexor digitorum superficialis. So, a trauma of the hand will affect the superficial muscles first before the deep (profundus) muscles are affected. Therefore, superficial finger flexor is the more correct answer.

Explanation

       Leprosy (Hansen’s disease) is a chronic generalized infectious disease, which involves mainly the ectoderm components (the skin, mucouc membranes and the peripheral nervous system), lymphatic nodes, liver, spleen, bones and endocrine glands. The causative agent is acid proof and alcohol-resistant Mycobacteria leprae. Three types of leprosy are distinguished: lepromatous; tuberculoid; undifferentiated (the first 2 are the main forms). In tuberculoid leprosy, the epidermis contains confluent granulomas composed of macrophages, plasma cells and leprous Virchow’s cells. Leprous Virchow’s cells (or leprosy/hansen’s cells) refer to large foamy macrophages within fatty vacuoles containing leprous mycobacterium.

Explanation

        Precipitation in agar(Precipitation gel reaction): antibody is incorporated into agar and antigen is inoculated i.e. antibody is the antidiphtheric antitoxic serum and the antigen is the diphtheria agent, inoculated in the nutrient agar. Antigen and antibody are placed in different wells in agar and allowed to diffuse and form concentration gradients. Where optimal proportions occur, lines of precipitate form. This method indicates whether antigens are identical, related but not identical or not related.

Areas of medium turbidity indicate where the antibody specific for the antigen have cross-linked.

Explanation

Explanation

At puberty, a pool of growing follicles is established and continuously maintained from the supply of primordial follicles. A primary oocyte, together with its surrounding flat epithelial cells forms the primordial follicle. Each month 15 – 20 follicles selected from this pool begin to mature, passing through 3 stages namely: primary or preantral; secondary or antral and preovulatory (graafian follicle). As the primary oocyte begins to grow, surrounding follicular cells change from flat to cuboidal and proliferate to produce a stratified epithelium (which can be 1 - 2 layers but usually more) of granulose cells and the unit is called a primary follicle.

Explanation

Tick-borne encephalitis is a disease caused by a flavivirus that affects the central nervous system. It is transmitted through the bite of an infected tick. A serum sample is obtained as soon as a viral etiology is suspected (acute phase) and a second sample is obtained 10-14days later (convalescent phase). If the antibody titer in the convalescent phase serum sample is at least fourfold higher than the titer in the acute phase serum sample, the patient is considered to be infected. For example, if the titer in the acute phase serum sample is ¼ and the titer in the convalescent phase serum sample is 1/16 or greater, the patient has had a significant rise in antibody titer and has been recently infected. If however, the titer in the convalescent phase serum is 1/8, this is not a significant rise (not diagnostic) and should not be interpreted as a sign of recent infection, but a second sample is obtained 10-14days later.

Explanation

Actinomycetes are true bacteria (related to Corynebacteria and Mycobacteria), but they form long, branching filaments that resemble the hyphae of fungi. They are gram positive but some (such as Nocardia asteroids) are also weakly acid-fast. There are two medically important organisms, Actinomyces israelii and Nocardia asteroids. Actinomyces israelii causes Actinomycosis (abscess with draining sinuses). Strictly anaerobic; it forms part of the normal flora of the oral cavity. Actinomycosis appears as a hard, nontender swelling that develops slowly and eventually drains pus through sinus tracts. In about 50% of cases, the initial lesion involves the face and neck.

Explanation

Explanation

        Chronic sepsis (chroniosepsis): this form of sepsis is characterized by durably availability, not healing of primary septic focus that progress into a chronic one. In organs and tissues, there is atrophy and dehydration are expressed. Brown atrophy is found in the liver, myocardium and striated muscles. The spleen is decreased.

Explanation

Chorioepithelioma or choriocarcinoma or gestational choriocarcinoma is a malignant neoplasm of trophoblastic cells derived from a previously normal or abnormal pregnancy. NB: trophoblast differentiates into 2 layers (cytotrophoblast and syncytiotrophoblast) in the 2^nd week of development of an embryo. Chorioepithelioma is a soft, fleshy, yellow-white tumor that usually has large pale areas of necrosis and extensive hemorrhages. Histologically, it does not produce chorionic villi and consists entirely of proliferating syncytiotrophoblasts and cytotrophoblasts.

Explanation

 Increase in cardiac workload can cause imbalances in oxygen (O₂) supply and demand to the heart itself. Blood supply to the heart occurs during diastole. Increase heart rate (↑HR) → ↓diastolic period → ischemia in myocardium. Ischemia, hypoxia, heart failure are associated with disruptions in intracellular Na⁺ and Ca⁺ concentration homeostasis of myocardial cells. A decrease efflux or increase influx of Na⁺ may cause cellular Na⁺ overload. Na⁺ overload is followed by an ↑influx of calcium (Ca²⁺) through Na⁺-Ca²⁺ exchanger. Failure to maintain the homeostasis of Na⁺ and Ca⁺ leads to electrical instability (arrhythmias), mechanical dysfunction (reduced contractility and ↑ diastolic tension) and mitochondrial dysfunction. These events increase ATP hydrolysis and decrease ATP formation and if left uncorrected, they cause cell injury and death → acute heart failure.

Explanation

Explanation

Monocytes are the precursors of the cells of the mononuclear phagocytic system. Monocytes are the largest of the white blood cells in a blood smear. They travel from the bone marrow to the body tissues, where they differentiate into the various phagocytes of the mononuclear phagocytic system i.e. connective tissue macrophages (histiocytes), osteoclasts, alveolar macrophages, perisinusoidal macrophages in the liver (kupffer cells) and macrophages of lymph nodes, spleen and bone marrow, among others. Monocytes remain in the blood for only about 3 days. Monocytes transform into macrophages, which function as antigen presenting cells in the immune system.

Explanation

Sulfonylurea are insulin secretagogues because they promote insulin release from the β-cells of the pancreas. The primary drugs used today are the 2^nd generation drugs – glibenclamide, glipizide, glimepiride etc. These agents are useful in the treatment of patients who have type 2 diabetes mellitus and cannot be managed by diet alone. Metformin is the only currently available biguanide; its classed as an insulin sensitizer. Acarbose – α glucosidase inhibitor. Butamide (tolbutamide) is also a sulfonylurea but is older and glibenclamide is more potent and used much more commonly. Actrapid (soluble insulin) is fast acting but not a sulfonylurea.

Explanation

Conduction is a way the body eliminates heat by means of direct contact with another object. Heat is transferred down the temperature gradient (i.e. from the object of higher temperature to the object of lower temperature). Conduction requires contact with another object (Key words:  in water).

Heat Radiation is a way the surface of the human body emits heat to the environment in the form of infrared rays. The amount of heat the body radiates to the environment is proportional to the surface of radiation area and to the difference between the mean values of skin and environment temperature. The surface radiation area is the total surface area of body parts that contact the air. Elimination of heat by radiation increases with a decrease in ambient temperature and decreases with its increase. It is possible to reduce elimination of heat by radiation via reduction of the surface of radiation area (“winding oneself into a ball”). Heat radiation does not require a medium for transfer of heat. (Key words: naked or lightly clothed).

Convection is a way the body eliminates heat by means of transferring heat via moving particles of air or water. To dissipate heat by means of convection, body surface shall be airflowed at a temperature that is lower than the temperature of the skin. At that, air layer contacting with the skin warms up, decreases its density, rises and is replaced by cooler, denser air. By increasing the speed of the air flow (wind, ventilation) heat emission increases significantly as well (forced convection). Convection requires convection current; current of gases or liquids (Key words: air over exposed area of skin).

Evaporation is a way the body dissipates heat to the environment by its evaporation via sweat or evaporation of moisture from the skin and respiratory tract mucous membranes of (“wet” heat loss). Evaporation closely related to relative humidity.

Explanation

Cardiac glycoside is the most appropriate in this case. Cardiac glycosides are glycosidic drugs of plant origin having cardiac inotropic property, increase myocardial contractility and output.

Corglyconum is short acting for acute cardiac insufficiency and administered intravenously.

Digitoxin is long-acting but basically administered orally and used mainly for chronic heart failure (also digoxin).

Cordiamin – analeptic; Adrenaline is commonly used in shocks and coma; 

Explanation

1     

Explanation

Explanation

Substances absorbed into the bloodstream from the intestine pass through the liver, where toxins are normally removed. Many of these toxins (such as ammonia) are normal breakdown products of the digestion of protein.  Ammonia is produced by amino acid metabolism and intestinal urease-positive bacteria. In physiological conditions, it is mostly present as ammonium (NH₄⁺) in serum. The urea or ornithine cycle, which is fully expressed in the liver exclusively, serves to converts NH₄⁺ to urea prior to renal excretion and to maintain low serum concentrations. 

NH₃ + α-ketoglutarate → Glutamate

α-ketoglutarate is used up which leads to:

·        ↑glutamate → ↑GABA (inhibitory neurotransmitter)

·        Inhibition of citric acid cycle/tricarboxylic acid cycle; this causes impairment of ATP formation.

·        Inhibition of metabolism of amino acids (impairment of transamination reactions).

NH₃ + Glutamate → Glutamine

Glutamine is an amide of glutamic acid which provides a non-toxic storage and transport form of ammonia (NH₃). Ammonia increase synthesis of glutamine in brain. Accumulation of glutamine in brain results in elevation of osmotic pressure in nervous cells leading to brain edema.

                                    NH₃ + H⁺ → NH₄⁺

In blood ammonia (NH₃) is represented as ammonium ion (NH₄⁺). Accumulation of ammonium ion impairs transport of ions (Na⁺, K⁺) through cell membranes and failure of transmission of nerve impulse.

            Urea cycle takes place exclusively in the liver, so in hepatic coma, urea level is low. Glutamine toxicity in brain is dependent on increased ammonia concentration.

Bilirubin toxicity will most likely be related to increase hemolysis, which is not the case in this question. Histamine is a biogenic amine produced from the amino acid histidine.

Explanation

Gametogenesis involves the generation of germ cells (gametes) through meiosis. Meiosis requires 2 cell divisions, meiosis I and II, in order to reduce the number of chromosomes to the haploid number of 23. At the beginning of meiosis I, germ cells replicate their DNA so that each of the 46 chromosomes is duplicated into sister chromatids. Homologous pairs then separate into two daughter cells, thereby reducing the chromosome number from diploid to haploid. Shortly thereafter, meiosis II separates sister chromatids (2 sister chromatids are joined in the middle by a centromere). Each gamete then conatins 23 chromosomes.

Metaphase is a stage of cell division in which chromosomes are at their most condensed and coiled stage and chromosomes are arranged along the equatorial plane during this phase. Cell division is usually studied during this phase.

Explanation

Type IV (cell mediated, delayed, cellular cytotoxicity): antibody-independent T-cell mediated reactions e.g. positive mantoux reaction (tuberculin test), hashimoto’s thyroiditis or transplant rejection etc.

Mantoux test is a type IV Hypersensitivity reaction (HSR), which involves macrophages,T-lymphocytes and lymphokines(cytokines). Mononuclear cells (lymphocytes,monocytes,macrophages).

Remember,it is antibody independent (i.e does not involve antibodies).

The Mantoux skin test should be read between 48 and 72hrs after administration. The basis of reading  is the presence or absence of induration, which may be determined by inspection and by palpation. A record should also be made of formation of vesicles, bullae, lymphangitis, ulceration and necrosis at the test site. The formation of vesicles, bullae or necrosis at the test site indicates positive result. A negative mantoux result usually signifies that the individual has never been exposed to Mycobacterium tuberculosis i.e. absence of cell mediated immunity to tuberculin.

Explanation

Ileal diverticulum or Meckel’s diverticulum is a congenital anomaly that occurs in 1-2% of the population. A remnant of the proximal part of the embryonic omphaloenteric duct (yolk stalk), the diverticulum usually appears as a finger-like pouch. It is always at the site of attachment of the omphaloenteric duct on the antimesenteric border (border opposite the mesenteric attachment) of the ileum. The diverticulum is usually located 30-60cm from the ileocecal junction in infants and 50cm in adults. It may be free (74%) or attached to the umbilicus (26%). Although its mucosa is mostly ileal in type, it may also include areas of acid-producing gastric tissue, pancreatic tissue or jejuna or colonic mucosa. An ileal diverticulum may become inflamed and produce pain mimicking that produced by appendicitis.

Explanation

        Sleep is the natural periodic state of rest for mind and body with closed eyes characterized by partial or complete loss of consciousness. Sleep is unconsciousness from which the person can be aroused by sensory or other stimuli. It is to be distinguished from coma, which is unconsciousness from which the person cannot be aroused. During sleep, most of the body functions are reduced to basal level or even below the basal level. Therefore, power inputs can be lower than basal level during sleep. Unlike rest where it remains at the basal level or higher.

Explanation

Defects in male genitalia:

Hypospadia: fusion of the urethral folds is incomplete and abnormal openings of the urethra occur along the inferior (undersite) surface of the penis, usually near the glans, along the shaft or near the base of the penis.

Epispadia is a rare abnormality (1/30000 births) in which the urethral meatus is found on the dorsum (superior) surface of the penis.

Explanation

Aldosterone produced in adrenal cortex (zona glomerulosa): causes increased sodium (Na⁺) reabsorption; increased potassium and hydrogen ions (↑K⁺, H⁺) excretion. They increase sodium (↑Na⁺) channel and Na⁺ /K⁺-pump insertion in principal cells of collecting duct; enhances K⁺ and H⁺ excretion by way of principal cell K⁺ channels and α-intercalated cell H⁺ ATPases of collecting duct. Therefore, increase in aldosterone → ↑ K⁺ in urine (excretion) and ↓ Na⁺ in urine (↑ reabsorption); And decreased aldosterone → ↓ K⁺ excretion (↓K⁺ in urine) and ↓ Na⁺  reabsorption (i.e. ↑Na⁺ in urine); same effects on sweats glands too.

Explanation

        Quadritubercular bodies/tectal plate is the dorsal portion of the midbrain comprises 4 colliculi – two superior and two inferior. The nuclei of colliculi are responsible for reflexes associated with sudden sound and visual stimuli (auditory and visual orientative reflexes); they also maintain consciousness. The nuclei give rise to the tectospinal tract. Superior or Anterior colliculi – visual orientative reflex; Inferior or Posterior colliculi – auditory orientative reflex.

Explanation

Explanation

Doxycycline is a tetracycline, broad spectrum antibiotic. Bacteriostatic; bind to 30s subunit of ribosome. All other options are not antibiotics.

Explanation

With no pathological condition recorded in the patient. The task of inspection can increase catecholamine concentration in blood due to activation of the sympathoadrenal system. Increased concentration of catecholamines (epinephrine, norepinephrine) can lead to vasospastic, prinzmetal, variant or rest-angina, due to coronary artery spasm. Symptoms are caused by decreased blood flow to the heart muscle from the spasm of the coronary artery.

Explanation

Explanation

Resection of forestomach: Vitamin B₁₂ deficiency, megalocytic, macrocytic anemia.

Resection of pyloric part of stomach: iron deficiency, microcytic anemia.

    Vitamin B₁₂ caused subacute combined degeneration – demyelination of dorsal columns, lateral corticospinal tracts and spinocerebellar tracts of spinal cord which produces paresthesia (sensation of limb numbness) and sensory ataxia. Absorption of Vitamin B₁₂ takes place in the stomach, when it has the castle’s intrinsic factor produced by parietal cells in the stomach. Resection of the forestomach can reduce the intrinsic factor produced, thereby reducing Vit. B₁₂ absorption → Vit. B₁₂ deficiency. The tongue is shiny, glazed and “beefy” (atrophic glossitis).

Explanation

     Olfactory receptors are situated in olfactory mucus membrane, which is the modified mucus membrane that lines upper part of nostril (superior nasal concha). Olfactory receptor cell is a bipolar neuron. Dendrite of this neuron is short and it has an expanded end called olfactory rod. From the olfactory rod, about 10-12 cilia arise. These cilia project to the surface of olfactory mucus membrane in the upper part of nostril. Mucus secreted by Bowman glands continuously lines the olfactory mucosa.

Explanation

Catarrhal inflammation is one of the morphologic patterns in acute inflammation. In this type, a surface inflammation is associated with greatly increased secretion of clear mucus (nasal discharges). Rhinitis is inflammation of mucous lining of the nose.

Explanation

Brainstem is the part of the brain formed by medulla oblongata, pons and midbrain. It contains many centers for regulation of vital functions in the body. Medulla oblongata has many important centers which control vital functions like the respiratory centers; vasomotor center; deglutition center; vomiting center; superior and inferior salivatory nuclei; cranial nerve nuclei; vestibular nuclei. Deglutition center regulates the pharyngeal and esophageal stages of deglutition. Disturbed cerebral circulation can disrupt proper functioning of these centers.

Explanation

        Thiamine (vitamin B₁): thiamine pyrophosphate (TPP) is the biologically active form of the vitamin, formed by the transfer of a pyrophosphate group from ATP to thiamine. Biological role of TPP: it is a component of pyruvate dehydrogenase and α-ketoglutarate dehydrogenase complexes catalyzing the reactions of oxidative decarboxylation of pyruvate and α-ketoglutarate (kreb’s cycle) i.e. it promotes energy formation from carbohydrates and lipids. It’s also a component of transketolase (pentose phosphate pathway of glucose oxidation) essential for fats and nucleic acids synthesis.

Pyruvate to acetyl CoA + CO₂ reaction

            If pyruvate dehydrogenase cannot function properly due to vitamin B₁ deficiency, then pyruvate will be accumulated in blood because it can’t be broken down.

Explanation

Starvation is a stage that appears when the organism doesn’t receive food at all or receives them in insufficient quantity or when the organism doesn’t assimilate it due to a pathology. Starvation can be complete or incomplete (quantitative and qualitative). Complete starvation can be without water (absolute starvation). Incomplete starvation occurs more often than complete starvation. Quantitative incomplete starvation appears when the organism doesn’t chronically receive the necessary quantity of energy with food for energy expenditures (i.e. the organism eats, but it is not enough in quantity). Esophageal stenosis (narrowing of esophagus) will greatly reduce the amount of food taken by the patient thereby leading to incomplete starvation. It is usually marked by a decrease in body mass (weight).

Explanation

Nephrotic syndrome is characterized by massive proteinuria (>3.5g/day) with hyperlipidemia, hypoalbuminemia (hypo- and dysproteinemia), edema etc. It may be primary (direct podocyte damage) or secondary (podocyte damage from systemic process e.g. diabetes). For example – focal segmental glomerulosclerosis, minimal change disease, membranous nephropathy, amyloidosis, diabetic glomerulonephropathy.

Explanation

Explanation

Osteomyelitis is the inflammation of bone caused by pyogenic organisms. Acute osteomyelitis is an infection of the bone of less than two weeks’ duration, which typically spreads hematogenously (acute hematogenous osteomyelitis). A delay in diagnosis may cause growth disturbance, deformity or even death. It typically affects the long bones (femur and tibia are the most commonly affected). Pathogenesis: preexisting focus/exogenous infection → infective embolus enters nutrient artery → trapped in a vessel in metaphysis and blocks the vessel → active hyperemia and polymorphonuclear cell exudates → hyperemia and immobilization causes decalcification proteolytic enzymes destroy bacteria and medullary elements → the debris increase and intramedullary pressure increases → follows paths of least resistance → passes through haversian canal and Volkmann canal → local cortical necrosis → enter subperiosteal space → strips periosteum → perforation of periosteum/reach joint by piercing capsule → enters soft tissue and may drain out.

Explanation

        Antidiuretic hormone (vasopressin) is secreted in response to decrease blood volume and increase plasma osmolarity. It binds to receptors on principal cells of collecting ductules causing increase number of aquaporins and increase water reabsorption which leads to decreased diuresis.

↓vasopressin → ↓H₂O reabsorption → polyuria

Explanation

Nephrotic syndrome is characterized by massive proteinuria (>3.5g/day) with hyperlipidemia, hypoalbuminemia (hypo- and dysproteinemia), edema etc. It may be primary (direct podocyte damage) or secondary (podocyte damage from systemic process e.g. diabetes). For example – focal segmental glomerulosclerosis, minimal change disease, membranous nephropathy, amyloidosis, diabetic glomerulonephropathy.

Explanation

Lipoma is a benign tumor of fatty tissue. It is the most frequent soft tissue tumor, arising in subcutaneous regions at any site but most commonly on the back, shoulder and neck. It may develop in every site where there is fat tissue. Lipomas are encapsulated, usually small yellow node with distinct (clear) borders.

Liposarcoma and fibrosarcoma are malignant with no distinct borders. Angioma is tumor of vessels; Fibroma and Fibrosarcoma are tumors of connective tissue.

Explanation

Morphine is the major analgesic drug contained in crude opium. Opoids exert their major effects by interacting with opoid receptors in the CNS and in other anatomic structures, such as the GIT and the urinary bladder. Severe respiratory depression can occur and result in death from acute opoid poisoning. A serious effect of the drug is stoppage of respiratory exchange in patients with emphysema or Cor pulmonale. In this case, there is dysregulation of the respiratory center in the CNS.

Explanation

Explanation

         Reference interval (adults): 60 – 80g/L

40g/L is low i.e. a low oncotic pressure.

Glomerular filtration rate (GFR) is inversely proportional to oncotic pressure/colloid osmotic pressure, which is exerted by plasma proteins in the glomerular capillary blood. When oncotic pressure is low, GFR increases. Reabsorption is decreased, because the low oncotic pressure is not sufficient to reabsorb water and other substances (cannot create enough pressure to reabsorb water and other substances).

Explanation

Ligamentum flava resides between the vertebral arches and consist of yellow elastic tissue. The clefts between the vertebral arches are covered by the ligamentum flava, which is the widest in the lumbar region. Therefore, these regions are used for the punctures of the vertebral canal to access the subarachnoid space. This procedure is actually performed on the L2 and L3 as well between the L3 and L4. Moreover, the puncture is also performed between the occipital bone and the first cervical vertebra piercing the atlanto-occipital membrane. In the thoracic region, the spinous processes overlap each other like a tile covering the arches of the lower vertebrae.

Explanation

The sinoatrial (SA) node is a small strip of modified cardiac muscle, situated in the superior part of lateral wall of right atrium, just below the opening of superior vena cava. The fibers of this node do not have contractile elements. SA node is called the pacemaker because the rate of production of impulse (rhythmicity) is higher in SA node than in other parts. The rate is 60-100/min and higher during tachycardia when stimulated by sympathetic effects. Atrioventricular (AV) node is 40-60/min.

Explanation

Sulfonylurea are insulin secretagogues because they promote insulin release from the β-cells of the pancreas. The primary drugs used today are the 2^nd generation drugs – glibenclamide, glipizide, glimepiride etc. These agents are useful in the treatment of patients who have type 2 diabetes mellitus and cannot be managed by diet alone. Metformin is the only currently available biguanide; its classed as an insulin sensitizer. Acarbose – α glucosidase inhibitor. Butamide (tolbutamide) is also a sulfonylurea but is older and glibenclamide is more potent and used much more commonly. Actrapid (soluble insulin) is fast acting but not a sulfonylurea.

Explanation

Vitamin K-dependent factors include factor II, VII, IX and X; protein C and S. vitamin K is activated in the liver by epoxide reductase. Activated vitamin K ɣ-carboxylates each of the vitamin K-dependent factors. Carboxylated factors are now able to bind calcium, which are essential for interaction between the coagulation factors and platelet membranes.

Factor II – Prothrombin

Factor VII – Stable factor

Factor IX – Christmas factor

Factor X – Stuart-Prower factor

These factors undergo vitamin K-dependent post-translational modification, whereby a number of their glutamic acid residues are carboxylated to form ɣ-carboxyglutamic acid residues. The ɣ-carboxyglutamyl residues bind calcium ions which are essential for interaction between the coagulation factors and platelet membranes.

Warfarin inhibits the enzyme vitamin K epoxide reductase. Neonates lack enteric bacteria which produce vitamin K.

Explanation

Liver is the primary organ of protein synthesis. In a case of dysfunction of protein synthesis, hypoproteinemia occurs. We have absolute and relative hypoproteinemia. Absolute is when there is disturbed synthesis (absolute hypoproteinemia) and in cases of increased synthesis (absolute hyperproteinemia); while relative does not have to do with synthesis but other pathologies e.g. renal lesions, in which case, there is loss of protein with urine (relative hypoproteinemia); also vomiting, diarrhea, profuse sweating can produce relative hyperproteinemia.

It is Relative because it does not have to do with synthesis. The man must have lost a lot of fluid through sweat, thereby decreasing the fluid content of the body and creating a relative hyperproteinemia. Decrease blood volume (liquid component alone) → ↑concentration of blood.

Explanation

Pulmonary embolism is the most common and fatal form of venous thromboembolism in which there is occlusion of pulmonary arterial tree by thromboemboli. Pulmonary emboli are more common in hospitalized or bedridden patients. The majority of emboli arise from the deep veins of the lower extremities; most of the fatal ones arise from the ileofemoral veins. Consequences of thromboembolism include pulmonary infarction in which pyramidal segments (or ‘triangular’ segments) of hemorrhagic infarction are seen at the periphery of the lung. Detachment of thrombi from the thrombophlebitis site in the lower limbs produces a thromboembolus that flows through venous drainage into the large veins draining into the right side of the heart and then to the pulmonary circulation where they embolize.

Explanation

Deltoid muscle …

 Origin: lateral third of clavicle, acromion of scapula, spine of scapula.

Insertion: Deltoid tuberousity of humerus.

Innervation: Axillary nerve ( a terminal branch of branchial plexus receiving fibres from C5 & C6 ventral rami.

Action:

Anterior part- flexion & medial (internal) rotation of the humerus at glenohumeral  joint.

Middle part- abduction of the humerus at the glenohumeral joint.

Posterior part – extension & lateral (external) rotation of the humerus at the glenohumeral joint.

Explanation

Triceps brachii is the chief extensor of the forearm at the humeroulnar joint. Has a long, lateral, and medial head. Inserts on olecranon of ulna bone.                                                                                 

Explanation

          Demodex folliculorum and Demodex brevis: they are species of face mite. When large numbers of D. folliculorum are found in humans, the infestation is known as Demodicosis. D. folliculorum is semi-transparent elongated organism consisting of a head, neck, body and tail. As an adult, it can measure 0.1-0.4mm in length and possess 4 pairs of short legs near its head and neck region. In the course of time, because of chronic progradient course, pathologic process results in formation of inflammatory nodes, infiltrates and persistent vascular dilatation. Hyperemia of facial skin and eruptions are also seen.

Explanation

The concept of trophic function of the nervous system arose early in the 19^th century owing to the attempts of clinicians and physiologists to account for the pathological changes occurring in tissues (ulcers, necrosis and atrophy) upon injury to the nervous system (trauma to peripheral nerve). These changes, known as neurogenic dystrophies take place when neuroregulation of metabolism in tissues is impaired by injury or chronic irritation of nerve trunks or by injury to the central nervous system, in particular, to the hypothalamus. In studies on the trophic function of the nervous system made during the 1920s, I. P. Pavlov  maintained that every organ is controlled by the nerves in 3 ways: Functional control arouses or arrests the activity of organs; Vascular control regulates the supply of nutrients by the blood and Trophic control regulates the utilization of nutrients by organs.

Explanation

Skin cancer (epithelial tumors) is divided into 4 groups:

·        Intraepidermal cancer (cancer in situ): Bowen’s disease, erythroplasia of Queyrat.

·        Basal cell carcinoma (BCC, basalioma)

·        Epidermoid cancer

·        Skin appendage cell carcinoma: Paget’s disease

Basal cell carcinoma (basalioma) is malignant; the tumor is characterized by slow growth (sometimes for years), locally destructive invasive growth without metastases and frequent recurrences. The tumor is of polymorphous structure derived from the epidermis and skin appendages. The most prevalent location is the face, neck and scalp. Gradually increasing in size, they can form a large plaque or node with ulcerative depression in the center and elevated borders. It has the appearance of a flat well-defined reddish, round or oval-shaped spot or plaque.

Explanation

Heparin is a natural anticoagulant produced in mast cells and basophils. It is an injectable, rapidly acting anticoagulant that is often used acutely to interfere with the formation of thrombi. Heparin is used in the prevention of venous thrombosis and the treatment of a variety of thrombotic diseases such as pulmonary embolism and acute myocardial infarction. Heparin binds to antithrombin III, with the subsequent rapid inactivation of coagulation factors. Antithrombin III inhibits serine proteases, including several of the clotting factors, most importantly, thrombin (factor IIa) and Factor Xa (a-active).

Protamine sulphate antagonizes the anticoagulant effects of heparin. The positively charged protamine interacts with the negatively charged heparin forming a stable complex without anticoagulant activity.

Explanation

Blood loss during trauma results in loss of all components of blood (cells and liquid component of blood). Therefore, the packed cell volume (PCV) or Hematocrit value will decrease after a blood loss. Erythropoiesis cannot replace all cells lost in 24hours. Therefore, the Hematocrit or PCV should not be up to 40% 24 hours after the bloodloss of about 750ml.

Explanation

The exam is a form of psychological stress causing the release of Stress hormones (catecholamines, cortisol). Stress-induced changes in blood leukocyte distribution may represent an adaptive response. This represents a redistribution of leukocytes from the blood to other organs such as the skin, draining sentinel lymph nodes and other compartments. Such leukocyte redistribution may enhance immune function in compartments to which immune cells traffic during stress.

Explanation

 Exocytosis is the process by which a vesicle moves from the cytoplasm to the plasma membrane, where it discharges its contents to the extracellular space. A variety of molecules produced by the cell for export are initially delivered from the site of their formation to the golgi apparatus. The next step involves sorting and packaging the secretory product into transport vesicles that are destined to fuse with the plasma membrane in a process known as exocytosis.

Explanation

Karakurt spider: the word kara meaning “black” and kurt meaning “worm” comes from the Turkic languages. It is black in colour and is identified by the thirteen (13) spots which are found on its dorsal abdomen. These spots are usually red in colour, but may also be yellow, or orange. The female has a body length of 1 – 2cm (10-20mm), while the male is smaller and reaches 0.5 – 0.8cm (5-8mm) at best. Only the female spider’s bite is dangerous (either for humans or cattle) as the male cannot penetrate the relatively thick epidermis.

Explanation

Explanation

Creatine kinase/Creatine phosphokinase is an enzyme present in striated muscles, used to generate energy. When its serum level is elevated it is often an indication of muscle damage caused by injury, muscular dystrophy or cardiac problems. Most forms of muscular dystrophy are associated with decreased creatinine excretion. Creatinine is a break down product of creatine. Normal constituent of urine but can be elevated in muscular dystrophy. Since creatine is not a normal constituent of urine, it is more specific in this case.

Explanation

Liver is the primary organ of protein synthesis. In a case of dysfunction of protein synthesis, hypoproteinemia occurs. We have absolute and relative hypoproteinemia. Absolute is when there is disturbed synthesis (absolute hypoproteinemia) and in cases of increased synthesis (absolute hyperproteinemia); while relative does not have to do with synthesis but other pathologies e.g. renal lesions, in which case, there is loss of protein with urine (relative hypoproteinemia); also vomiting, diarrhea, profuse sweating can produce relative hyperproteinemia.

Albumin is a major component of plasma protein ( proteinemia - albuminemia)

Explanation

Blood group O(I): no antigens, therefore no agglutination.

Blood group A(II): A antigen, agglutinate with blood group B(III) and O(I).

Blood group B(III): B antigen, agglutinate with blood group A(II) and O(I).

Blood group AB(IV): A and B antigen, agglutinate with all blood groups. No antibody.

Blood group name is determined by the antigen present on RBC, but the patient has an opposite antibody. So whenever, the antibody corresponds to the antigen, there is agglutination. Since O does not have any antigen, no agglutination can occur.

Explanation

        Neurons are classified on the basis of the number of processes extending from the cell body:

·        Pseudounipolar: neurons have one process (extension), which divides close to the cell body into two long processes (axon and dendrite). The vast majority are located in the dorsal root ganglia and cranial nerve ganglia.

·        Unipolar neurons have only one pole. From a single pole, both axon and dendrite arise. This type of nerve cells is present only in embryonic stage in human beings.

·        Bipolar neurons have two poles – one axon and one dendrite.

·        Multipolar neurons have many poles – one axon and two or more dendrites.

Explanation

Rickets results from insufficiency of vitamin D (calcitriol). Calcitriol is the active form of vitamin D. calcitriol production is dependent on the kidney’s 1-α-hydroxylase which converts 25-OHD₃ to 1,25-(OH)₂D₃ (calcitriol). So in cases of renal lesion, there is lack of 1-α-hydroxylase which leads to a deficiency of calcitriol or impaired synthesis of calcitriol.

Explanation

The embryonic period or period of organogenesis occurs from the third – eighth weeks of development and is the time when each of the 3 germ layers: ectoderm, mesoderm and endoderm, give rise to a number of specific tissues and organs.

Explanation

     The process of transcription of a typical gene can be divided into 3 phases: initiation, elongation and termination. The process of transcription begins with the binding of the RNA polymerase holoenzyme to a region of the DNA known as the promoter. RNA polymerase is a multisubunit enzyme that recognizes a nucleotide sequence (the promoter region) at the beginning of a length of DNA that is to be transcribed. It makes a complementary RNA copy of the DNA template strand and then recognizes the end of the DNA sequence to be transcribed (the termination region).

Explanation

Fluoroquinolones: ciprofloxacin, norfloxacin, levofloxacin, ofloxacin, moxifloxacin. They are all antibiotics. They inhibit prokaryotic enzymes topoisomerase II (DNA gyrase) and topoisomerase IV. They are bactericidal and must not be taken with antacids. It is contraindicated in pregnant women, nursing mothers and children

Fluoroquinolones hurt attachments to your Bones.

Explanation

     Picornaviruses are small nonenveloped viruses composed of an icosahedral nucleocapsid and a single-stranded RNA genome (ssRNA). Picornavirus family ncludes two groups of medical importance: the enteroviruses and rhinoviruses. Among the major enteroviruses are the poliovirus, coxsackieviruses, echoviruses and hepatitis A virus.

Coxsackieviruses are named for the town of Coxsackie, NY, where they were first isolated. Coxsackievirus cause a variety of diseases. Coxsackieviruses are divided into group A and group B viruses based on early observations of their pathogenicity in newborn mice (mouse sucklings). Group A causes flaccid paralysis while group B causes spastic paralysis. Coxsackie A virus causes paralysis and death of the mice; coxsackie B causes less severe infection in the mice.

Explanation

        Fibrosing alveolitis is also known as interstitial pneumonia. It is characterized by progressive scarring of both lungs. The scarring (fibrosis) involves the supporting framework (interstitium) of the lung. There are patchy or lobar areas of congestion without the consolidation of bacterial pneumonias. A predominance of interstitial pneumonitis with widened, edematous alveolar walls containing a mononuclear inflammatory cell infiltrates. Interstitial pneumonia is the most common form of interstitial fibrosis.

Explanation

Atrioventricular (AV) node serves as the gateway for conduction of impulses from the atria to the ventricle. Stimulation of the parasympathetic nerves to the heart (vagus nerve) causes the neurotransmitter acetylcholine to be released at the vagal endings. This neurotransmitter has two major effects on the heart. First, it decreases the rate of rhythm of the sinus node, and second, it decreases the excitability of the AV junctional fibers between the atrial musculature and the AV node, thereby slowing transmission of the cardiac impulse into the ventricles. In the AV node, a state of hyperpolarization caused by vagal stimulation makes it difficult for the small atrial fibers entering the node to generate enough electricity to excite the nodal fibers. A moderate decrease simply delays conduction of the impulse, but a large decrease blocks conduction entirely.

Explanation

Muscarinic receptors belong to the class of G protein-coupled receptors. These receptors, in addition to binding Acetylcholine, it also recognizes muscarine – an alkaloid that is present in certain poisonous mushrooms. Muscarinic effects include miosis, spasm of accommodation, increasing of lacrimal, salivary, gastrointestinal, bronchial and sweat glands secretion, increase of smooth muscle tonus of internal organs, bradycardia, decreased arterial pressure.

M-cholinoreceptors increase muscle tonus of internal organs. Therefore blocking this receptor will relieve the bronchospasm.

Explanation

Explanation

          Protein mechanism is one of the molecular mechanisms of cell injury. The protein mechanism of cell damage includes:

·        Inhibition of enzymes (reversible and irreversible)

·        Denaturation – violation of native structure of proteins

·        Proteolysis – that is carried out under the action of lysosomal enzymes.

Explanation

DiGeorge’s syndrome results from a congenital malformation affecting the 3^rd and 4^th pharyngeal pouches. These structures give rise to the thymus, parathyroid glands and portions of lips, ears and the aortic arch. It is the most common disorder of cell mediated immunity. The thymus is usually rudimentary and T cells are deficient or absent in the circulation. Most of these infants have additional developmental defects affecting the face, ears, lips heart and great vessels. All of these disorders are part of a spectrum called 22q deletion syndrome because they result from a deletion on the long arm of chromosome 22 (22q11). It represents the most severe example of a collection of disorders that also includes velocardiofacial syndrome (VCFS) and conotruncal anomalies face syndrome.

Explanation

Vitamin K is essential for the formation of various clotting factors in the liver, namely clotting factor II, VII, IX and X; Protein C and S.

Factor II – Prothrombin

Factor VII – Stable factor

Factor IX – Christmas factor

Factor X – Stuart-Prower factor

These factors undergo vitamin K-dependent post-translational modification, whereby a number of their glutamic acid residues are carboxylated to form ɣ-carboxyglutamic acid residues. The ɣ-carboxyglutamyl residues bind calcium ions which are essential for interaction between the coagulation factors and platelet membranes. This oral anticoagulants block epoxide reductase and creation of active form of vitamin K resulting in disturbances in prothrombin and proconvertin synthesis in liver.

Deficiency of vitamin K → ↓clotting factors → prolongation of coagulation time → hemorrhages.

Explanation

Somatic cell division is a cyclic process divided into two phases: mitosis (M phase) and interphase. Three other phases, Gap 1 (G₁); synthesis phase (S) and Gap 2 (G₂) further subdivide interphase. M phase is followed by G₁.

M phase: karyokinesis – division of the nucleus into two daughter nuclei.

                  Cytokinesis – division of the cell into two daughter cells.

G₁: a period in which no DNA synthesis occurs.

Period of cell growth S or DNA synthesis phase follows G₁ phase. The DNA of the cell is doubled. The S phase is followed by a period in which no DNA synthesis occurs, a second gap or G₂ phase. A cell that leaves the cycle in G₁ phase to begin “terminal” differentiation enters the G₀ phase, (“O” stands for “outside” the cycle).

Explanation

Explanation

     The drop in arterial pressure (AP) will cause a reflex tachycardia, the heart increases its contractility and cardiac output. Vasoconstriction will be minimal in the heart, because the heart needs to pump more i.e. do more work. Therefore, it needs more blood supply. But vasoconstriction will be maximal in the GIT (bowels), muscles, skin due to centralization of blood flow (i.e. redistribution of blood to important organs like heart, brain)

Explanation

Autosomal dominant: often due to defects in structural genes. Many generations, both male and female are affected. Found in every generation; no generation is left out (skipped). Parent – child in every generation.

Autosomal recessive is usually seen in some generations (other generations are skipped).

It is sex linked, if only males or only females(X-linked) are affected.

Explanation

Explanation

Explanation

         Hydrochlorothiazide is a thiazide diuretic. Thiazide diuretics induce hypokalemia and hyperuricemia in 70% of patients and hyperglycemia in 10% of patients. Serum potassium levels should be monitored closely in patients who are predisposed to cardiac arrhythmias (particularly individuals with left ventricular hypertrophy, ischemic heart disease or chronic heart failure) and those who are concurrently being treated with both thiazide diuretics and digoxin. In general, decreased serum levels of potassium predispose a patient to digoxin toxicity.

Explanation

         Gluconeogenesis is making of glucose from non-carbohydrate sources i.e. fat and proteins. During a prolonged fast, hepatic glycogen stores are depleted and glucose is formed from precursors such as lactate, pyruvate, glycerol (derived from backbone of triacylglycerols) and α-ketoacids (derived from the catabolism of glucogenic amino acids). Amino acids derived from hydrolysis of tissue proteins (e.g. muscle proteins) are the major sources of glucose during a fast. α-ketoacids such as oxaloacetate and α-ketoglutarate are derived from the metabolism of glucogenic amino acids. Amino acids whose catabolism yields pyruvate or one of the intermediates of citric acid cycle (CAC) are termed glucogenic or glycogenic e.g. alanine, arginine, aspartate, histidine etc.

Explanation

Metronidazole forms toxic free radical metabolites in the bacterial cell that damage DNA. It is bactericidal, and an antiprotozoal. It is used to treat Giardia, Entamoeba, Trichomonas, Gardnerella vaginalis, Anaerobes (bacteroides, Clostridium difficile). It can be used with a proton pump inhibitor and clarithromycin for “triple therapy” against Helicobacter pylori.

Explanation

Resection of forestomach: Vitamin B₁₂ deficiency, megalocytic, macrocytic anemia.

Resection of pyloric part of stomach: iron deficiency, microcytic anemia.

    Vitamin B₁₂ caused subacute combined degeneration – demyelination of dorsal columns, lateral corticospinal tracts and spinocerebellar tracts of spinal cord which produces paresthesia (sensation of limb numbness) and sensory ataxia. Absorption of Vitamin B₁₂ takes place in the stomach, when it has the castle’s intrinsic factor (gastromucoprotein) produced by parietal cells in the stomach. Resection of the forestomach can reduce the intrinsic factor produced, thereby reducing Vit. B₁₂ absorption → Vit. B₁₂ deficiency. The tongue is shiny, glazed and “beefy” (atrophic glossitis).

Explanation

Accumulation is enhancing of the effects in repeated doses that leads to the appearance of toxic effects. It can be:

·        Material accumulation: is accumulation of drug in the manner of bindings with proteins, phospholipids etc.

·        Functional accumulation is accumulation of the drug’s effect in spite of its elimination.

Explanation

Enlargement of the muscular wall of the ventricles (myocardial hypertrophy) is an important compensatory mechanism of the heart in cardiac failure. When the heart must work harder, the heart’s wall enlarge and thicken. At first, the thickened heart walls can contract more forcefully. However, the thickened heart walls eventually become stiff, causing or worsening diastolic dysfunction. Myocardial hypertrophy is a long-term compensatory mechanism. Cardiac muscle, like skeletal muscle, responds to an increase in work demands by undergoing hypertrophy. Hypertrophy increases the number of contractile elements in myocardial cells as a means of increasing their contractile performance.

Explanation

At rest, the axon membrane is slightly polarized to about -70mV (or -80mV), meaning the intracellular fluid (ICF) is relatively negative to the extracellular fluid (ECF). An action potential occurs when a portion of the membrane rapidly depolarizes and then repolarizes again to the original resting state. The process is initiated by a threshold level stimulus, such as a nearby change in membrane potential (threshold potential, local potential). At threshold (about -55mV), many Na⁺ voltage-gated channels open. Na⁺ ions entering the cell make the membrane potential less negative. More Na⁺ channels open as a result and a cycle of depolarization develops. When the membrane potential reaches about +30mV (reverse polarization), the timed Na⁺ channels close due to inactivation and the Na⁺ influx stops. K⁺ voltage-gated channels open as Na⁺ channels close, in a delayed response to the original stimulus.

Explanation

Explanation

Vagus nerve gives parasympathetic innervations to the heart. The vagal fibers are distributed mainly to the atria and not much to the ventricles, where the power contraction of the heart occurs. This explains the effect of vagal stimulation mainly to decrease heart rate rather than to decrease greatly the strength of heart contraction.

Explanation

Embolism is occlusion of a vessel by material travelling in the circulation.

* Fat/Adipose embolism: obstruction of arterioles and capillaries by fat globules constitutes fat embolism. It may occur following severe fracture trauma to bones, inflammation of bones and soft tissues, fatty liver

* Thromboembolism: a detached thrombus or part of thrombus which may arise in the arterial or venous circulation.

* Gas embolism: two main forms of gas embolism are air embolism and decompression sickness. Air embolism is usually due to accidental pumping of air into the venous circulation during intravenous (IV) injection or transfusion ( bubble – air escaped).

Tissue embolism: fragments of tissue.

Explanation

Myocarditis is inflammation of the heart myocardium. Microvascular plethora and diffuse stroma infiltration with lymphocytes and histiocytes are indicative of an inflammatory process taking place in the heart. Heart failure, dilated heart cavities are complications of myocarditis.

Explanation

Explanation

          The morphologic changes in acute viral hepatitis are virtually the same regardless of the causative agent and can be mimicked by drug reactions. Grossly, the liver is slightly enlarged. Histologically, the major finding is hepatocellular injury characterized by necrosis of scattered hepatocytes; isolated liver cells or small cell clusters appear as eosinophilic rounded-up cells (apoptotic bodies, councilman’s bodies). Degenerated hepatocytes may also appear ballooned. Macrophages may phagocytize the necrotic hepatocytes and may accumulate clumps of lymphocytes and macrophages. Confluent necrosis may lead to bridging necrosis connecting portal-to-portal, central-to-central or portal-to-central regions of adjacent lobules, signifying a more severe form of acute hepatitis.

Explanation

Trapezius is a flat, triangular muscle, whose base is facing the spinous processes of the vertebrae. It resides in the upper part of the back and the occiput. The right and left trapezius muscles together form a trapezoid.

Origin: the external occipital protuberance, the superior nuchal line, the ligamentum nuchae and the spinous processes of vertebrae C₇ - T₁₂.

Insertion: the spine of the scapula, the acromion and the lateral third of the clavicle.

Action: adducts, rotates, elevates and depresses the scapula.

Nuchal region – neck region

Explanation

Vestibular nuclei receive impulses concerned with muscle tone and posture from vestibular apparatus and cerebellum. Vestibular nuclei in turn convey the impulses to different parts of the body through the anterior and lateral vestibulospinal tracts. Vestibulospinal tracts are concerned with adjustment of position of head and body during angular and linear acceleration; maintenance of muscle tone and posture; position of head and body during acceleration. Therefore, increase transmission of impulse through this tract leads to increase tone. Extensor muscles are also for balance (connected to vestibular apparatus). The inputs from the otolith organs project mainly to the lateral vestibular nucleus, which in turn sends axons in the lateral vestibulospinal tract to the spinal cord. The input from this tract exerts a powerful excitatory influence on the extensor (antigravity) muscles. When hair cells in the otolith organ are activated, signals reach the medial part of the ventral (anterior, motor) horn. By activating the ipsilateral (same side) pool of motor neurons innervating extensor muscles in the trunk and limbs, this pathway mediates balance and the maintenance of upright posture.

Explanation

Septicopyemia is a form of sepsis, main attributes of which are purulent processes in the entrance of infection and bacterial embolism with formation of abscesses in many organs and tissues. At the dissection, there is primary septic focus, it is usually in the entrance of infection with purulent lymphangitis and lymphadenitis. At first metastatic abscesses appear in the lungs, then in the liver, kidneys (apostematous nephritis), spleen is septic, hyperplastic processes in blood – creating lymphatic tissues.

Explanation

The receptor areas of the vestibular labyrinth are represented with the following structures:

·        Macula of Utricle

·        Macula of Saccule

·        Ampullary crests

Explanation

Tay- sachs disease is a progressive neurodegeneration, developmental delay, “cherry-red” spot on macula, lysosomes with onion skin, no hepatosplenomegaly. It is an autosomal recessive disease, caused by the deficiency of hexosaminidase A resulting in the accumulation of GM₂ ganglioside in organs of the body (e.g. brain, liver, spleen).

Explanation

        Hodgkin’s disease or lymphogranulomatosis is a disorder involving primarily the lymphoid tissue. It is separated from non-hodgkin lymphoma because:

First, it is characterized morphologically by the presence of distinctive neoplastic giant cells called Reed-sternberg’s cells, admixed with a variable inflammatory infiltrate.

Secondly, it is often associated with distinctive clinical features, including systemic manifestations such as fever.

Reed-sternberg cell: classically, it is a large cell, most often binucleate or bilobed, with two halves often appearing as mirror images of each other. Its identification is essential for the histologic diagnosis. The origin of Hodgkin’s lymphoma is unknown.

Explanation

Metastases of breast cancer is either local or distant. Local metastases is usually to the lymphatic nodes of breast base, axilla, subclavicular, parasternal nodes. Distant metastases are hematogenic ones, 40-50% to the bones, lungs, and liver.

Cancer of any of the following will metastasize locally through:

            Submandibular salivary gland – submandibular nodes

            Thyroid gland – deep anterior cervical nodes

            Stomach – celiac nodes

            Lungs – visceral thoracic lymph nodes

The dominant lymphatic drainage from the right upper lobe flowed into the superior mediastinal nodes. The sternal or parasternal nodes is one of the superior mediastinal nodes.

Explanation

High IgM level usually indicate an acute or primary infection because, it is the first antibody to appear in response to initial exposure to an antigen. Secondary or reinfection show an increase in IgG. IgM antibodies appear early in the course of an infection, this makes it useful in the diagnosis of infectious diseases. Demonstrating IgM antibodies in a patient’s serum indicates recent infection or in a neonate’s serum, it indicates intrauterine infection.

Explanation

Explanation

The mucosa layer of the bronchi is composed of pseudostratified epithelium with the same cellular composition as the trachea. The basal cells serve as a reserve cell population (regenerative property) that maintains individual cell replacement in the epithelium. Basal cells tend to be prominent because their nuclei form a row in close proximity to the basal lamina. Although nuclei of other cells reside at this same general level within the epithelium, they are relatively sparse. Thus, most of the nuclei near the basement membrane belong to basal cells.

Explanation

 Secondary tuberculosis usually results from reactivation of dormant, endogenous tubercle bacilli in a sensitized patient who has had previous contact with the tubercle bacillus. Reactivation typically begins in the apical or posterior segments (often 1^st and 2^nd segments) of one or both upper lobes (“simon’s foci”), where the organisms were seeded during the primary infection. There are 8 forms or stages of the secondary tuberculosis: Acute local tuberculosis; Fibrous local tuberculosis; Infiltrative tuberculosis; Tuberculoma; Caseous pneumonia; Acute cavernous tuberculosis; Fibrous cavernous tuberculosis; Cirrhotic tuberculosis.

Fibrous cavernous tuberculosis is the most frequent form. Macroscopically, the lesions are spherical and cavitary (cavity can contain blood and blood clots); the so-called coin lesions. Microscopically, the outer wall of cavity shows fibrosis or sclerosis. Internal surface may be connected with bronchus. The wall of cavern has 3 membranes:

·        Internal membrane occurs by necrotic tissue

·        Middle membrane occurs by special granular tissue

·        External membrane occurs by connective fibrous tissue

Acute cavernous tuberculosis develops due to lyses of caseous necrosis and characterized by formation of the round cavity.

Explanation

Evaporation is a way the body dissipates heat to the environment by its evaporation via sweat or evaporation of moisture from the skin and respiratory tract mucous membranes of (“wet” heat loss). Evaporation closely related to relative humidity.

Heat Radiation is a way the surface of the human body emits heat to the environment in the form of infrared rays. The amount of heat the body radiates to the environment is proportional to the surface of radiation area and to the difference between the mean values of skin and environment temperature. The surface radiation area is the total surface area of body parts that contact the air. Elimination of heat by radiation increases with a decrease in ambient temperature and decreases with its increase. It is possible to reduce elimination of heat by radiation via reduction of the surface of radiation area (“winding oneself into a ball”). Heat radiation does not require a medium for transfer of heat. (Key words: naked or lightly clothed).

Convection is a way the body eliminates heat by means of transferring heat via moving particles of air or water. To dissipate heat by means of convection, body surface shall be airflowed at a temperature that is lower than the temperature of the skin. At that, air layer contacting with the skin warms up, decreases its density, rises and is replaced by cooler, denser air. By increasing the speed of the air flow (wind, ventilation) heat emission increases significantly as well (forced convection). Convection requires convection current; current of gases or liquids (Key words: air over exposed area of skin).

Conduction is a way the body eliminates heat by means of direct contact with another object. Heat is transferred down the temperature gradient (i.e. from the object of higher temperature to the object of lower temperature). Conduction requires contact with another object (Key words:  in water).

Explanation

In the urogenital tract, the flagellate protozoa, Trichomonas vaginalis is the important pathogen. Trichomonas vaginalis causes trichomoniasis. It is a pear-shaped organism with a central nucleus and four anterior flagella. It has an undulating membrane that extends about two-thirds of its length. It exists only as a trophozoite; there is no cyst form. The organism is transmitted by sexual contact and the primary locations of the organism are the vagina and the prostate. In women, a watery, foul-smelling, greenish vaginal discharge accompanied by itching and burning occurs.

Explanation

           I^AI^O                  I^BI^O

   I^AI^B   I^AI^O        I^BI^O        I^OI^O

This is the only combination that can produce a group I (I^OI^O) and a group IV (I^AI^B) blood groups.

Explanation

       Hypoosmolar hypohydration (salt deficit) develops due to diarrhea, vomiting, sweating, adrenal insufficiency, hypokalemia, CNS lesions, salt-losing nephritis.

          Hyperosmolar hypohydration (water defcit) develops due to the loss of the fluid which lacks electrolytes e.g. in diabetes insipidus, hyperventilation.

          Isoosmolar hypohydration (isoosmotic loss): proportional volume decrease of fluids and electrolytes e.g. in blood loss, burns, diuretic therapy, especially diarrhea in cholera.

         Hypoosmolar hyperhydration (water excess) develops in acute renal failure (in the stage of anuria), Parhon’s syndrome (syndrome of inappropriate ADH secretion –SIADH).

         Hyperosmolar hyperhydration (salt excess) develops rarely e.g. in drinking salt (sea) water, infusion of hypertonic saline, adrenal hyperactivity or steroid therapy.

    Low water level extracellularly – Hypohydration

    Low blood osmolarity – Hypoosmolar           

                Hypoosmolar hypohydration

Explanation

Allotransplantation: from an individual (donor) to another

Autotransplantation: from one part of the body to another (e.g. skin on thigh to         face).

Xenotransplantation and Heterotransplantation: from one specie to another (e.g. pig to human)

Explantation: removal of a body tissue/organ

Explanation

The tunics of veins are not as distinct or well defined as the tunics of arteries. Veins are divided into 3 types:

* Small veins/venules: postcapillary and muscular venules

* Medium veins

* Large veins

Arteries:

·        Large or elastic arteries

·        Medium or muscular arteries

·        Small arteries and arterioles

Muscular venules are distinguished from postcapillary venules by the presence of a tunica media. Postcapillary venules possess an endothelial lining with its basal lamina and pericytes. Postcapillary venules have no true tunica media.

·        Tunica intima: consists of endothelium with its basal lamina

·        Tunica media: smooth muscle cells

·        Tunica adventitia: collagen fibers

A vessel without tunica media, also lack muscular tissue. Muscular artery, arteriole and artery of mixed type all have tunica media. Only capillaries and postcapillary venules lack tunica media.

Also a prominent internal elastic membrane helps to distinguish muscular arteries from elastic arteries and muscular venules.

Explanation

Mesenchyme refers to loosely organized embryonic connective tissue regardless of origin. Undifferentiated embryonic mesenchymal cells are round/cuboidal in shape. During development, visceral myogenesis is shortly preceded by mesenchymal cell elongation. Undifferentiated embryonic mesenchymal cells from intestine (abundant visceral muscle), lung (some visceral muscle) or kidney (no visceral muscle); these cells differentiate into smooth muscle upon elongation.

Explanation

Parietal (oxyntic) cells are found in the neck of the fundic glands, among the mucus neck cells and in the deeper part of the gland. They secrete HCl and intrinsic factor. When examined with the transmission electron microscope they are seen to have an extensive intracellular canalicular system that communicates with the lumen of the gland. Also an elaborate tubulo-vesicular membrane system is present in the cytoplasm adjacent to the canaliculi. Numerous mitochondria with complex cristae and many matrix granules supply the high levels of energy necessary for acid secretion.

Explanation

Explanation

Atherosclerosis is a multifactorial disease that affects the intima of elastic arteries. The disease is characterized by intramural deposits of lipids, proliferation of vascular smooth muscle cells and fibroblasts and accumulation of macrophages. The risk is correlated with elevated low density lipoprotein (LDL), formed from the catabolism of very low density lipoprotein (VLDL) to a cholesterol ester-protein core that carries some 70% of the total serum cholesterol. Atheroma is specifically associated with high blood LDL levels (as well as total cholesterol levels). Risks is inversely related to the HDL levels, perhaps because high density lipoprotein (HDL) helps clear cholesterol from vessels.

HDL – Good cholesterol

LDL – Bad cholesterol

Explanation

Proserin (neostigmine) is an indirect acting cholinergic agonist (anticholinesterase). It preserves endogenous acetylcholine which can stimulate a greater number of acetylcholine receptors at the muscle endplate. Thereby increasing intestinal peristalsis and tone of urinary bladder.

Explanation

For the heart to beat at 40bpm, it means that the SA node is no longer functional in that heart (the AV node has taken over the function of SA node; normal AV node discharge impulses at 40-60bpm). A cardiac electric stimulator that was implanted that discharge impulses at the rate of 70bpm will now take over the function of Sinoatrial (SA) node that beats normally within the range of 60-80bpm (60-80 beats per minute).

Explanation

Acetylcholine is a neurotransmitter. It increases salivary secretion and stimulates intestinal secretions and motility. It increases bronchial secretions, increases tone of detrusor urinae muscle, causing expulsion of urine, stimulates ciliary muscle contraction (accommodation). It increases exocrine gland secretions (e.g. lacrimal, salivary, gastric acid); gut peristalsis, bladder contraction, bronchoconstriction, papillary sphincter muscle contraction (miosis). Poisoning by cholinomimetics causes diarrhea, urination, miosis, bronchospasm, bradycardia, excitation of skeletal muscle and central nervous system, lacrimation, sweating and salivation. Cholinomimetics are cholinergic agonists which produce analogous effects of acetylcholine.

Explanation

Type IV (cell mediated, delayed, cellular cytotoxicity): antibody-independent T-cell mediated reactions e.g. positive mantoux reaction (tuberculin test), hashimoto’s thyroiditis or transplant rejection etc.

Explanation

Hypertension of any etiology is characterized by an increased blood pressure. Of which, the heart must overcome this pressure each time it wants to pump blood out. This increased blood pressure in essential hypertension and hypertensive crisis leads to an increase in workload on the heart, increasing the normal pressure the heart is meant to pump against (↑ afterload). This increase in workload, overtime, can lead to cardiac insufficiency as a result of the excessively increased blood pressure.

Explanation

Abstinence syndrome is renewal or deterioration of the disease after cessation of the drug administration. It is the withdrawal symptoms that occur after abstinence/stoppage of a drug, especially after taking the drug for some relatively long time (e.g. a narcotic).

       deterioration of the disease: 'impairment of psychic...'

Explanation

Metronidazole forms toxic free radical metabolites in the bacterial cell that damage DNA. It is bactericidal, and an antiprotozoal. It is used to treat Giardia, Entamoeba, Trichomonas, Gardnerella vaginalis, Anaerobes (bacteroides, Clostridium difficile). It can be used with a proton pump inhibitor and clarithromycin for “triple therapy” against Helicobacter pylori.

Explanation

Antishock phase of shock is when the compensatory mechanisms of the body are activated to antagonize the devastating effects of shock. Shock is characterized by decrease in blood pressure, which leads to decrease blood circulation, but in the antishock phase, stress hormones such as corticosteroids and catecholamines (epinephrine, norepinephrine) and the whole sympathoadrenal system are fully active to prevent decrease in blood pressure and other characteristics of shock. Epinephrine, cortisol (glucocorticoids) have the capacity to increase blood pressure, increase glucose concentration; increase respiration (ventilation) etc. the antishock phase is a component of the compensatory stage of shock.

Explanation

Myasthenia gravis is an autoimmune disease of neuromuscular junction caused by antibodies to cholinergic receptors. It is characterized by grave weakness of the muscle due to the inability of neuromuscular junction to transmit impulses from nerve to the muscle. It is caused due to the development of auto-antibodies (IgG auto-antibodies) against the receptors of acetylcholine. That is, the body develops antibodies against its own acetylcholine receptors. These antibodies prevent binding of acetylcholine with its receptors or destroy the receptors. So, though the acetylcholine release is normal, it cannot execute its action.

Explanation

Gastric acid secretion by parietal cells of the gastric mucosa is stimulated by acetylcholine, histamine and gastrin. Histamine binding causes activation of adenylyl cyclase, whereas binding of prostaglandin E₂ inhibits this enzyme. Gastrin and acetylcholine acts by inducing an increase in intracellular calcium levels (it is evident that blocking acetylcholine receptor wouldn’t stop acid secretion, because gastrin can do the same work with the same mechanism). Therefore, it is more effective to block Histamine receptors. Antagonists of the histamine H₂ receptor, blocks the action of histamine at all H₂ receptors but their chief clinical use is to inhibit gastric acid secretion, being particularly effective against nocturnal acid secretion. H₂-receptor blockers include cimetidine (Tagamet), ranitidine, famotidine, nizatidine. NB: H₁-receptor blocker – loratadine (for allergic reactions).

Explanation

Neurinoma or Schwannoma is a benign tumor of peripheral nervous system. It is formed of spinder-like cells with rod-shaped nuclei. The cells and fibers form rhythmical structures. An acoustic neurinoma is a benign tumor that may develop on the hearing and balance nerves (CNVIII vestibulocochlear nerve) near the inner ear. The tumor results from an overproduction of Schwann cells – small sheet-like cells that normally wrap around nerve fibers like onion skin and help support the nerves.

Explanation

        Types of lymph-circulatory insufficiency:

·        Mechanical insufficiency

·        Dynamic insufficiency

·        Insufficiency of absorption/Resorption insufficiency

Mechanical insufficiency is present where lymph flow is hindered by a mechanical factor. The mechanical factor may be of an anatomical, organic nature e.g. occlusion of lymphatics by obstructive lymphangitis, thrombosis of the lymphatics (e.g. during cancer metastasis), filariasis.

The other two types has to do with a disbalance of proteins that upsets the filtration and absorption pressures.

Explanation

The pituitary gland (hypophysis) is composed of glandular epithelial tissue and neural (secretory) tissue. The hypophysis consists of two major subdivisions; the adenohypophysis and the neurohypophysis. The adenohypophysis is further subdivided into the pars distalis (anterior lobe), pars tuberalis and pars intermedia. The neurohypophysis is divided into the pars nervosa (infundibular process), infundibulum and tuber cinereum of the median eminence. The pars distalis contains two main cell types, chromophobe cells and chromophil cells. The chromophils (chromophilic cells) are subdivided into acidophils (alpha cells) and basophils (beta cells).

Explanation

         What forms the walls of the ingunal canal:

·        Anteriorly: the aponeuroses of the external and internal oblique muscles.

·        Posteriorly: the transversalis fascia.

·        Superiorly: the arching fibers of the internal oblique and transverses abdominis muscles.

·        Inferiorly: the inguinal ligament.

Contents:

·        Men: Spermatic cord (funiculus spermaticus) and the ilioinguinal nerve

·        Women: round ligament of the uterus (ligamentum teres uteri) and the ilioinguinal nerve.

      Since the gender was not specified in the question, then it means the question s referring to inguinal canal content in men, which is the Funiculus spermaticus.

Explanation

        Loratadine is an antihistamine (antiallergic drug) which refers to the classic H₁-receptor blocker. These compounds do not influence the formation or release of histamine. Rather, they block the receptor-mediated response of a target tissue. They are much more effective in preventing symptoms than reversing them once they have occurred. These agents, desloratadine, fexofenadine, and loratadine show the least sedation i.e. least effect on CNS (they don’t induce sleep).

Explanation

The symptoms describe cardiac insufficiency. Cardiac glycoside is the most appropriate in this case. Cardiac glycosides are glycosidic drugs of plant origin having cardiac inotropic property, increase myocardial contractility and output. Corglyconum is short acting for acute cardiac insufficiency and administered intravenously.

Digitoxin is long-acting but basically administered orally and used mainly for chronic heart failure (also digoxin).

Cordiamin – analeptic; Adrenaline is commonly used in shocks and coma; 

Explanation

Shock is a form of stress which is accompanied by the release of stress hormones (catecholamines, cortisol). Stress-induced changes in blood leukocyte distribution may represent an adaptive response. This represents a redistribution of leukocytes from the blood to other organs such as the skin, draining sentinel lymph nodes and other compartments. Such leukocyte redistribution may enhance immune function in compartments to which immune cells traffic during stress.

Explanation

α₂-macroglobulin and α₁-antitrypsin are protease inhibitors which can inhibit the pancreatic proteases and prevent further tissue protein breakdown. 

Explanation

          Penicillins  are β-lactam antibiotics that inhibit the synthesis of bacterial cell walls and are considered bactericidal too. They bind penicillin binding proteins (transpeptidases) and block transpeptidase cross-linking of peptidoglycan in cell wall. They also activate autolytic enzymes. Benzylpenicillin is a short acting penicillin.

Explanation

* Pleiotropy: one gene defect contributes to multiple phenotypic effects → disorder of connective tissue and eye lens structure, abnormalities of CNS, arachnodactylia. Marfan is FBN1 gene mutation on chromosome 15; Marfan and Hartnup is one gene defect causing multiple phenotypic defects; likewise Hartnup disease (digestive and Urinary systems)

* Codominance: both alleles contribute to the phenotype of the heterozygote. e.g. blood group AB

Explanation

        Doses of bromides have to be determined individually. The bromides are excreted from the organism rather slowly (50-60days), so they may be accumulated and cause the signs of chronic poisoning (bromism). The irritative action of bromides leads to inflammation of the mucous membranes which is accompanied by cough, rhinitis, conjunctivitis and diarrhea.

Explanation

Explanation

Diphtheria bacteria (Corynebacterium diphtheria) is Gram positive, pleomorphic, often club-shaped rods and are arranged in palisades or in V (at an angle) or L-shaped formations. Media used for isolation are Tellurite agar & Lὄffler medium. Lὄffler nutrient medium consists of coagulated serum & nutrient broth. Selective indicator medium containing tellurite are used in selective culturing. K tellurite is used to inhibit the accompanying flora.

Explanation

Vitamin K is essential for the formation of various clotting factors in the liver, namely clotting factor II, VII, IX and X; Protein C and S.

Factor II – Prothrombin

Factor VII – Stable factor

Factor IX – Christmas factor

Factor X – Stuart-Prower factor

These factors undergo vitamin K-dependent post-translational modification, whereby a number of their glutamic acid residues are carboxylated to form ɣ-carboxyglutamic acid residues. The ɣ-carboxyglutamyl residues bind calcium ions which are essential for interaction between the coagulation factors and platelet membranes. This oral anticoagulants block epoxide reductase and creation of active form of vitamin K resulting in disturbances in prothrombin and proconvertin synthesis in liver.

Deficiency of vitamin K → ↓clotting factors → prolongation of coagulation time → hemorrhages.

Explanation

Norepinephrine (noradrenaline), epinephrine (adrenaline) and dopamine are catecholamines produced in chromaffin cells of adrenal medulla from tyrosine. The catecholamines are inactivated by oxidative deamination catalyzed by monoamine oxidase (MAO) and by O-methylation carried out by Catechol-O-methyltransferase. The metabolic products of these reactions are excreted in the urine as vanillymandelic acid from epinephrine and norepinephrine; and homovanillic acid from dopamine.

Explanation

Methotrexate is structurally related to folic acid and acts as an antagonist of that vitamin by inhibiting dihydrofolate reductase (in humans), which is the enzyme that converts folic acid to its active coenzyme form, tetrahydrofolic acid. Trimethoprim and pyrimethamine inhibit the same enzyme but in bacteria and protozoa respectively. This decreases dTMP, needed for DNA synthesis.

Explanation

Autosomal dominant: often due to defects in structural genes. Many generations, both male and female are affected. Found in every generation; no generation is left out (skipped). Parent – child in every generation.

Autosomal recessive is usually seen in some generations (other generations are skipped).

It is sex linked, if only males or only females(X-linked) are affected.

Explanation

Tuberculin (Mantoux) skin test: this test is done by intradermal injection of tuberculoprotein (tuberculin), purified protein derivative (PPD). Type IV hypersensitivity reaction.

Immunization against tuberculosis is induced by injection of attenuated strains of bovine type of tubercle bacilli, Bacilli Calmette Guerin (BCG).

Explanation

Explanation

     The ureter connects the renal pelvis with the urinary bladder. It is 30cm long, 5-6mm in diameter and lies extraperitoneally (i.e. devoid of peritoneal investment). Each ureter has 3 parts: abdominal, pelvic and intramural parts. Entering the pelvic inlet, the right ureter crosses the right external iliac artery and the left crosses the left common iliac artery. In females, the ureters run posterior to the broad ligament of uterus and then along the free border of ovary. Laterally to the cervix of uterus, the ureters loop around the inferior border of the broad ligament cross the uterine vessels at a right angle and pass between the anterior wall of vagina and the urinary bladder to reach the fornix of the latter posteriorly.

Explanation

Acute poisoning with narcotic analgesics (e.g. morphine) is characterized by sleep or unconsciousness, normal or increased reflexes, normal muscle tone, miosis, bradycardia, cheyne-stokes breath, the retention of urine, a spasm of intestine and bowel. This condition can be treated with:

·        Stomach lavage with 0.5% solution of potassium permanganate.

·        Intravenous injection of Naloxone (naloxone is an antagonist of narcotic analgesic).

·        Atropine; for decrease in the vagal action of morphine.

Explanation

Explanation

We have acute, subacute and chronic glomerulonephritis. Subacute glomerulonephritis does not necessarily follow acute attacks. It is usually characterized by the general symptoms of glomerulonephritis like proteinuria, hematuria, edema and azotemia persisting for many days and even weeks. Renal changes include those of rapidly progressive and membranoproliferative glomerulonephritis.    “DEMILUNE”

Explanation

The anterior group of muscles of the pelvic girdle comprises the flexors, which includes the iliopsoas (iliacus and psoas major muscles) and psoas minor muscle. The iliopsoas consists of two muscles – the psoas major and iliacus. The psoas major is a thick, elongated fusiform muscle, which extends from the lumbar region downward, occupying the space between the bodies of the vertebrae and their transverse processes. The muscle becomes narrower below, and passing under the inguinal ligament, it fuses with the iliacus muscle. The psoas major is a major component of the renal bed together with other muscles such as the diaphragm, quadratus lumborum and transverse abdominis muscle.

Explanation

The axillary nerve (nervus axillaris) from brachial plexus, is the greatest branch of the short branches of brachial plexus. It arises from the posterior cord and proceeds to the quadrangular/quadrilateral foramen. It supplies the deltoid and teres minor muscles. The axillary nerve and posterior circumflex humeral artery pass through the quadrangular space. Borders of the quadrangular space:

·        Superior: Teres minor

·        Inferior: Teres major

·        Medial: Long head of triceps

·        Lateral: humerus

Explanation

Stromal vascular carbohydrate degenerations develop due to disturbance of glycosaminoglycans and glycoproteids metabolism. When glycoproteid metabolism is disturbed, chromotropic substances are released from the protein bonds. They accumulate in the main substance of the connective tissue. Collagen fibers change into mucus-like mass. Connective tissue mucin is associated with:

·        Mucoid or myxoid degeneration in some tumors (myxomas)

·        Neurofibromas, soft tissue sarcomas etc

·        Myxomatous change in the dermis in myxedema

·        Myxoid change in the synovium in ganglion on the wrist.

The condition results in colliquative necrosis with formation of cavities filled with mucus.

Explanation

     Granular or rough endoplasmic reticulum (i.e. rough surface) is a region of endoplasmic reticulum associated with ribosomes. It is the site of protein synthesis and modification of newly synthesized proteins.