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Maharashtra HSC Medical Lab Technology (Vocational) study materials
Maharashtra HSC Medical Lab Technology (Vocational) study resources

Maharashtra HSC Medical Lab Technology (Vocational) practice questions

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Question 1Laboratory Safety, First Aid, Ethics and Quality Control

Which document should a laboratory technician consult before handling an unfamiliar chemical reagent to learn its hazards and emergency measures?

  1. Equipment calibration certificate
  2. Safety data sheet (SDS) Correct answer.
  3. Internal quality control chart
  4. Patient report format

Explanation

A safety data sheet (SDS), formerly called MSDS, is the standard document that lists a chemical's hazards, safe handling, first-aid measures, and spill response. It must be readily accessible in the laboratory. Calibration and quality control documents do not describe chemical hazards.

Question 2Laboratory Safety, First Aid, Ethics and Quality Control

Under the Biomedical Waste Management Rules, discarded blood bags and blood samples are segregated into which colour-coded bin?

  1. Red
  2. Blue
  3. White translucent
  4. Yellow Correct answer.

Explanation

Yellow-category waste includes human anatomical waste, soiled waste, expired or discarded blood and blood components, and clinical laboratory waste. Such waste is incinerated or treated as specified in the rules. Red, white, and blue bins are used for contaminated recyclable plastics, sharps, and glassware respectively.

Question 3Laboratory Safety, First Aid, Ethics and Quality Control

A technician spills concentrated hydrochloric acid on the forearm. What is the correct immediate first-aid measure?

  1. Flush with running water Correct answer.
  2. Apply oily burn ointment
  3. Rub with alcohol-soaked cotton
  4. Neutralise with bicarbonate solution

Explanation

Immediate copious irrigation with running water for at least 15 minutes is the first-aid measure for acid or alkali skin splashes. Contaminated clothing should be removed under the stream. Chemical neutralisation and ointments are not recommended because they can generate heat or delay effective dilution.

Question 4Laboratory Safety, First Aid, Ethics and Quality Control

A patient's relative telephones the laboratory and asks for the patient's HIV test result. What is the ethically appropriate response?

  1. Ask for written consent Correct answer.
  2. Send a mobile photo
  3. Disclose only to a spouse
  4. Read the result aloud

Explanation

HIV results are sensitive personal information and may not be disclosed to a relative without the patient's informed consent. The laboratory should politely refuse and ask the relative to obtain written authorisation from the patient or to contact the treating clinician. Confidentiality is a core ethical and legal duty in medical laboratory practice.

Question 5Laboratory Safety, First Aid, Ethics and Quality Control

A single internal quality control value falls beyond the mean ±3 SD on a Levey-Jennings chart. What is the most appropriate action?

  1. Report patient results with a comment
  2. Stop reporting and investigate the control failure Correct answer.
  3. Ignore the value if the other level is in control
  4. Recalibrate without repeating the control

Explanation

A single control result outside mean ±3 SD violates the 1-3s rule and indicates that the analytical run should be rejected. Patient results should not be reported until the cause is identified and the control is repeated successfully. Immediate recalibration without investigation may mask the true problem.

Question 6Laboratory Safety, First Aid, Ethics and Quality Control

A phlebotomist receives a needle-stick injury from a used needle. What is the first action to take?

  1. Wash with soap and water Correct answer.
  2. Request the patient's HIV report
  3. Start post-exposure prophylaxis at once
  4. Squeeze the wound and apply bleach

Explanation

The wound should be washed immediately with soap and running water; squeezing the wound or applying bleach is not recommended. After washing, the injury must be reported so that the source patient can be assessed and post-exposure prophylaxis started if indicated. Obtaining the patient's HIV report or starting medicines is not the first step.

Question 7Laboratory Safety, First Aid, Ethics and Quality Control

At a voluntary counselling and testing centre, what must be obtained before a client's blood is collected for HIV testing?

  1. A doctor's oral instruction
  2. Informed consent after counselling Correct answer.
  3. Consent from the spouse
  4. Approval from the laboratory head

Explanation

HIV testing requires informed consent, usually after pre-test counselling, and must respect the client's confidentiality. Consent from a spouse or a doctor's instruction cannot substitute for the client's own consent. The laboratory head's approval is an administrative requirement, not patient consent.

Question 8Laboratory Safety, First Aid, Ethics and Quality Control

Two consecutive control values for the same level fall beyond +2 SD on a Levey-Jennings chart. Which conclusion is correct?

  1. Discard the control as expired
  2. Reject run for systematic error Correct answer.
  3. Accept the run as random error
  4. Report results after a warning

Explanation

The 2-2s rule is violated when two consecutive control values fall beyond the same ±2 SD limit, which suggests systematic error. The analytical run should be rejected and the cause corrected before patient results are reported. A single value beyond 2 SD is only a warning, but two consecutive values trigger rejection.

Question 9Laboratory Safety, First Aid, Ethics and Quality Control

For a small xylene fire in a laboratory, which extinguishing agent is most appropriate?

  1. Wet chemical extinguisher
  2. Pressurised water extinguisher
  3. Carbon dioxide extinguisher Correct answer.
  4. Water mist extinguisher

Explanation

Flammable solvents such as xylene are Class B fires, and carbon dioxide extinguishers are suitable because they smother the fire without spreading the liquid or leaving residue. Water-based extinguishers can spread burning solvent and are dangerous. Wet chemical extinguishers are intended for cooking oil fires.

Question 10Laboratory Safety, First Aid, Ethics and Quality Control

A laboratory receives a proficiency testing report showing a satisfactory result for glucose but an unsatisfactory result for creatinine. What is the most appropriate interpretation?

  1. Investigate creatinine testing Correct answer.
  2. Stop all laboratory testing
  3. Report creatinine without change
  4. Ignore the unsatisfactory score

Explanation

An unsatisfactory proficiency testing result for one analyte indicates a possible problem with that specific method, calibration, or operator technique. The laboratory should investigate creatinine testing while recognising that satisfactory glucose performance does not guarantee other tests are reliable. Patient results should be reviewed and corrective action documented.

Question 11Laboratory Safety, First Aid, Ethics and Quality Control

A laboratory assistant must prepare a dilute sulfuric acid solution from concentrated sulfuric acid. Which procedure is safe?

  1. Add water slowly to the concentrated acid while stirring.
  2. Add the concentrated acid slowly to water while stirring. Correct answer.
  3. Mix the acid and water quickly in a closed bottle.
  4. Add the acid to hot water to speed up mixing.

Explanation

The rule is always to add concentrated acid to water, not water to concentrated acid. Dilution releases heat, and adding water to acid can cause sudden boiling and spattering. Slow stirring and appropriate personal protective equipment are also required.

Question 12Laboratory Safety, First Aid, Ethics and Quality Control

A sharps container in the sample collection room has reached the manufacturer's fill line. What is the correct action?

  1. Empty it into a yellow biomedical waste bag.
  2. Press the sharps down and continue using the container.
  3. Close and replace it with a new sharps container. Correct answer.
  4. Store it open until the end of the shift.

Explanation

Sharps containers must be closed and replaced when they reach the fill line, usually about three-quarters full. Overfilling or pressing down the contents causes needle-stick injuries. The sealed container is then handled as biomedical waste according to institutional policy.

Question 13Laboratory Safety, First Aid, Ethics and Quality Control

A technician must handle a small volume of chloroform at the laboratory bench. Which control measure is most appropriate?

  1. Perform the work inside a functioning chemical fume hood. Correct answer.
  2. Perform the work on the open bench near the doorway.
  3. Perform the work inside the specimen refrigerator.
  4. Perform the work beside the autoclave.

Explanation

Chloroform is volatile and potentially harmful by inhalation, so it should be handled in a functioning chemical fume hood. Working on an open bench or near heat sources increases exposure. A refrigerator is for storage, not for manipulating volatile chemicals.

Question 14Laboratory Safety, First Aid, Ethics and Quality Control

A technician splashes dilute sodium hydroxide into one eye while preparing reagents. What is the correct immediate first-aid measure?

  1. Neutralize the alkali with dilute hydrochloric acid before flushing.
  2. Irrigate the eye with clean water for at least 15 minutes. Correct answer.
  3. Apply antibiotic eye drops immediately and then resume laboratory work.
  4. Rub the eye with a dry tissue to remove the chemical.

Explanation

Chemical splash to the eye requires immediate, prolonged irrigation with clean water or saline, usually for at least 15 minutes. Neutralizing agents and eye drops are not substitutes for irrigation and may cause further injury. The technician should also seek medical evaluation after flushing.

Question 15Laboratory Safety, First Aid, Ethics and Quality Control

A blood collection tube breaks on the laboratory bench, spilling blood. After putting on gloves, what is the correct next step?

  1. Pick up the broken glass with gloved fingers and place it in a red bag.
  2. Spray water over the spill and allow it to air-dry completely.
  3. Cover the spill with absorbent material, apply disinfectant, then clean the area. Correct answer.
  4. Wipe the spill immediately with a dry cloth and discard the cloth in general waste.

Explanation

A blood spill should be contained and disinfected before cleaning; freshly prepared sodium hypochlorite is commonly used. Broken glass must not be picked up by hand because of sharps injury risk. The area should be cleaned carefully, and waste disposed of as biomedical waste.

Question 16Laboratory Safety, First Aid, Ethics and Quality Control

Which vaccine is specifically recommended for laboratory personnel who regularly handle blood specimens?

  1. Hepatitis C vaccine
  2. Hepatitis B vaccine Correct answer.
  3. HIV vaccine
  4. Malaria vaccine

Explanation

Hepatitis B is a bloodborne virus and a safe effective vaccine is available; vaccination is recommended for laboratory staff exposed to blood. Hepatitis C and HIV have no licensed preventive vaccine. Malaria is not transmitted through blood specimen handling in the laboratory.

Question 17Laboratory Safety, First Aid, Ethics and Quality Control

On a Levey-Jennings chart, one control value exceeds the mean +2 SD but stays within ±3 SD. Which Westgard rule treats this finding as a warning rather than a rejection?

  1. R-4s rule
  2. 2-2s rule
  3. 4-1s rule
  4. 1-2s rule Correct answer.

Explanation

The 1-2s rule is a warning rule: one control result outside ±2 SD but within ±3 SD prompts inspection of other rules before rejecting the run. The 2-2s, R-4s and 4-1s rules are rejection rules when their criteria are met. A single value beyond ±3 SD violates the 1-3s rule and is also rejectable.

Question 18Laboratory Safety, First Aid, Ethics and Quality Control

A patient's employer telephones the laboratory and asks for the patient's complete blood count report. What is the most appropriate response?

  1. Read the results to the employer because the employer paid for the test.
  2. Send the report to the employer by ordinary post without checking consent.
  3. Verify the caller's identity and the patient's authorization before releasing any result. Correct answer.
  4. Refuse to speak and hang up without giving any explanation.

Explanation

Laboratory results are confidential and may be released only to authorized persons, following the laboratory's policy and applicable law. The technician should confirm identity and consent rather than disclose results to an employer by telephone. A polite explanation of confidentiality is better than simply ending the call.

Question 19Laboratory Safety, First Aid, Ethics and Quality Control

A creatinine control at one level has remained approximately 1.5 SD above the mean for seven consecutive runs, while the other control level is within limits. What does this pattern most likely indicate?

  1. Transcription error in the control log.
  2. Random error caused by a single pipetting variation.
  3. Pre-analytical error limited to one patient sample.
  4. Systematic error from calibration or reagent lot problem. Correct answer.

Explanation

A control value persistently on one side of the mean across consecutive runs indicates bias, which is a systematic error. Common causes include calibration drift, a new reagent lot, or a change in control material. Random error produces scattered values, not a sustained shift.

Question 20Laboratory Safety, First Aid, Ethics and Quality Control

A laboratory plans to use leftover patient samples for a research study. Which requirement is most appropriate before the samples are used?

  1. Permission from the company that manufactures the test reagents.
  2. A signed consent form from every patient, even when samples are fully anonymous.
  3. Approval by an institutional ethics committee, with consent or a documented waiver. Correct answer.
  4. Approval by the laboratory supervisor alone, without ethical review.

Explanation

Research use of leftover patient samples requires ethics committee review and a clear consent process, or a formal waiver when consent is impracticable. A supervisor's approval alone is not sufficient ethical oversight. Consent requirements depend on the study and local rules, not on reagent manufacturers.

Question 21Basic Human Anatomy, Physiology and General Pathology

In a stained peripheral blood smear from a healthy adult, which leukocyte is normally the most abundant?

  1. Eosinophil
  2. Lymphocyte
  3. Monocyte
  4. Neutrophil Correct answer.

Explanation

Neutrophils account for roughly 40–75% of circulating leukocytes in adults and are identified by their segmented nuclei and pale granules. Lymphocytes are the second most common, while eosinophils and monocytes are minor populations. This makes the neutrophil the expected predominant leukocyte on a normal differential count.

Question 22Basic Human Anatomy, Physiology and General Pathology

Which ABO/Rh blood group is described as the universal donor for red cell transfusion?

  1. AB positive
  2. O negative Correct answer.
  3. A positive
  4. B negative

Explanation

O negative red cells lack A, B, and Rh D antigens, so they can be transfused to recipients of any ABO and Rh type without causing immediate antibody-mediated hemolysis. This is why O negative is used as the universal red cell donor group, particularly in emergencies. AB positive plasma is sometimes called universal plasma, but it is not the universal red cell donor.

Question 23Basic Human Anatomy, Physiology and General Pathology

The structural and functional unit of the kidney is the:

  1. Hepatocyte Correct answer.
  2. Nephron
  3. Sarcomere
  4. Alveolus

Explanation

Each kidney contains about one million nephrons, and each nephron consists of a renal corpuscle and a renal tubule. The nephron performs filtration, reabsorption, secretion, and concentration of urine. Alveoli belong to the lung, hepatocytes to the liver, and sarcomeres to muscle.

Question 24Basic Human Anatomy, Physiology and General Pathology

Classic haemophilia (haemophilia A) is caused by deficiency of which clotting factor?

  1. Factor IX
  2. Factor XI
  3. Factor VII
  4. Factor VIII Correct answer.

Explanation

Haemophilia A results from an X-linked deficiency of factor VIII, while haemophilia B (Christmas disease) is due to factor IX deficiency. Factor VIII acts as a cofactor for factor IXa in the intrinsic tenase complex that activates factor X. Prolonged activated partial thromboplastin time with a normal prothrombin time is typical.

Question 25Basic Human Anatomy, Physiology and General Pathology

Which respiratory volume cannot be determined by standard spirometry alone?

  1. Inspiratory reserve volume
  2. Expiratory reserve volume
  3. Residual volume Correct answer.
  4. Tidal volume

Explanation

Spirometry measures the volumes of air moved into and out of the lungs, including tidal volume and the inspiratory and expiratory reserve volumes. Residual volume is the air remaining in the lungs after a maximal expiration and cannot be exhaled into a spirometer. It is therefore measured indirectly, for example by helium dilution or body plethysmography.

Question 26Basic Human Anatomy, Physiology and General Pathology

Which mediator is stored preformed in mast cell granules and produces immediate vasodilation during acute inflammation?

  1. Interleukin-1
  2. Prostaglandin E2
  3. Leukotriene B4
  4. Histamine Correct answer.

Explanation

Histamine is synthesized and stored in mast cell and basophil granules and is released within minutes of injury or allergen exposure. It binds H1 receptors on endothelial cells, causing vasodilation and increased vascular permeability. Prostaglandins and leukotrienes are newly synthesized from arachidonic acid, while interleukin-1 is a cytokine.

Question 27Basic Human Anatomy, Physiology and General Pathology

On a standard electrocardiogram, the P wave represents which electrical event?

  1. Ventricular repolarization
  2. Atrioventricular nodal delay
  3. Ventricular depolarization
  4. Atrial depolarization Correct answer.

Explanation

The P wave is produced by depolarization of the atria, spreading from the sinoatrial node through atrial myocardium. Ventricular depolarization produces the QRS complex, and ventricular repolarization produces the T wave. Atrioventricular nodal delay is reflected mainly in the PR segment rather than a separate wave.

Question 28Basic Human Anatomy, Physiology and General Pathology

Which hormone lowers blood glucose by increasing cellular glucose uptake and glycogen synthesis?

  1. Glucagon
  2. Cortisol
  3. Insulin Correct answer.
  4. Adrenaline

Explanation

Insulin is released by pancreatic beta cells and promotes glucose entry into muscle and adipose tissue through GLUT4 translocation. It also stimulates glycogen synthesis and inhibits hepatic glucose output, thereby lowering blood glucose. Glucagon, cortisol, and adrenaline are counter-regulatory hormones that tend to raise blood glucose.

Question 29Basic Human Anatomy, Physiology and General Pathology

A 30-year-old woman with menorrhagia has microcytic hypochromic anemia. Which laboratory result best supports iron deficiency rather than anemia of chronic disease?

  1. High transferrin saturation
  2. High serum ferritin
  3. High MCV
  4. High TIBC Correct answer.

Explanation

In iron deficiency, low iron stores lead to a compensatory increase in total iron-binding capacity, while serum ferritin is low. Transferrin saturation is reduced, and the MCV is low or normal rather than high. In anemia of chronic disease, ferritin is often normal or raised and TIBC is low or normal.

Question 30Basic Human Anatomy, Physiology and General Pathology

Why does warfarin take several days to achieve a full anticoagulant effect after therapy is started?

  1. It lowers synthesis of vitamin K-dependent clotting factors Correct answer.
  2. It is cleared from plasma very rapidly by the kidneys
  3. It directly inhibits thrombin and other activated clotting factors in plasma
  4. It requires hepatic conversion to an active metabolite

Explanation

Warfarin inhibits vitamin K epoxide reductase, thereby decreasing hepatic synthesis of functional factors II, VII, IX, and X. The anticoagulant effect is delayed because previously synthesized factors remain in the circulation, with factor II having a relatively long half-life. Therefore, bridging with heparin is often required when rapid anticoagulation is needed.

Question 31Basic Human Anatomy, Physiology and General Pathology

Which circulating cell lacks a nucleus and carries oxygen bound to haemoglobin?

  1. Segmented neutrophil
  2. Platelet fragment
  3. Small lymphocyte
  4. Erythrocyte Correct answer.

Explanation

Mature mammalian erythrocytes lose their nucleus during development and are packed with haemoglobin, which transports oxygen. Neutrophils and lymphocytes are nucleated leukocytes, and platelets are anucleate cell fragments that support haemostasis but do not carry haemoglobin.

Question 32Basic Human Anatomy, Physiology and General Pathology

A dietary deficiency of which vitamin directly impairs DNA synthesis and produces megaloblastic anaemia?

  1. Cholecalciferol
  2. Phylloquinone
  3. Ascorbic acid
  4. Cobalamin Correct answer.

Explanation

Cobalamin (vitamin B12) is a cofactor for methionine synthase, which regenerates tetrahydrofolate needed for thymidylate and DNA synthesis. Deficiency causes nuclear-cytoplasmic asynchrony and megaloblastic anaemia. Ascorbic acid, phylloquinone, and cholecalciferol do not drive this pathway.

Question 33Basic Human Anatomy, Physiology and General Pathology

Which layer of skin is avascular and contains actively dividing keratinocytes in its basal layer?

  1. Subcutaneous layer
  2. Dermis
  3. Epidermis Correct answer.
  4. Hypodermis

Explanation

The epidermis is a stratified squamous keratinized epithelium that lacks blood vessels; its basal layer contains mitotically active keratinocytes. The dermis and subcutaneous tissue contain blood vessels and support the epidermis.

Question 34Basic Human Anatomy, Physiology and General Pathology

A blood specimen is collected for routine prothrombin time testing. Which anticoagulant should the collection tube contain?

  1. Sodium heparin
  2. Sodium fluoride
  3. Potassium EDTA
  4. Sodium citrate Correct answer.

Explanation

Sodium citrate is the anticoagulant for coagulation studies because it reversibly chelates calcium, which can be restored by recalcification in the assay. EDTA and heparin interfere with clotting tests, and fluoride is used for glucose preservation.

Question 35Basic Human Anatomy, Physiology and General Pathology

Which nephron segment actively reabsorbs sodium chloride while being impermeable to water, thereby diluting the tubular fluid?

  1. Thick ascending limb Correct answer.
  2. Thin descending limb
  3. Proximal convoluted tubule
  4. Medullary collecting duct

Explanation

The thick ascending limb reabsorbs sodium, potassium, and chloride via the Na-K-2Cl cotransporter while its luminal membrane is water-impermeable. This creates a dilute tubular fluid and a hypertonic medullary interstitium. Loop diuretics act here.

Question 36Basic Human Anatomy, Physiology and General Pathology

Which heart valve prevents backflow of blood from the left ventricle into the left atrium during systole?

  1. Tricuspid valve
  2. Pulmonary valve
  3. Aortic valve
  4. Mitral valve Correct answer.

Explanation

The mitral (bicuspid) valve lies between the left atrium and left ventricle and closes during ventricular systole, preventing backflow into the atrium. The aortic valve guards the left ventricular outflow; the tricuspid and pulmonary valves are right-sided.

Question 37Basic Human Anatomy, Physiology and General Pathology

In a chronic inflammatory lesion, which cell type is typically the predominant phagocyte and often forms multinucleated giant cells?

  1. Eosinophil
  2. Basophil
  3. Segmented neutrophil
  4. Macrophage Correct answer.

Explanation

Macrophages are derived from circulating monocytes and dominate chronic inflammation, where they phagocytose debris and can fuse into multinucleated giant cells. Neutrophils dominate acute inflammation; eosinophils are linked to parasites and allergy; basophils release histamine.

Question 38Basic Human Anatomy, Physiology and General Pathology

A blood smear from a patient with severe bacterial sepsis shows neutrophils with toxic granulation and Döhle bodies. These changes indicate which process?

  1. Accelerated granulopoiesis Correct answer.
  2. Aplastic marrow failure
  3. Iron overload
  4. Megaloblastic erythropoiesis

Explanation

Toxic granulation and Döhle bodies are cytoplasmic changes in neutrophils that reflect accelerated granulopoiesis and retention of primary granule contents during severe infection. They are part of the left shift, not evidence of megaloblastic change, iron overload, or marrow failure.

Question 39Basic Human Anatomy, Physiology and General Pathology

A 55-year-old man with liver cirrhosis has a markedly raised serum alpha-fetoprotein and a liver mass. Which diagnosis is most likely?

  1. Chronic hepatitis C without malignancy
  2. Hepatic haemangioma
  3. Hepatocellular carcinoma Correct answer.
  4. Metastatic colorectal carcinoma

Explanation

Markedly elevated alpha-fetoprotein in a cirrhotic liver with a mass strongly suggests hepatocellular carcinoma. AFP is a well-recognized marker for HCC, whereas colorectal metastases more often raise CEA and benign haemangiomas do not produce such marked AFP elevation.

Question 40Basic Human Anatomy, Physiology and General Pathology

Which hormone released from the posterior pituitary directly increases water reabsorption in the collecting duct?

  1. Adrenocorticotropic hormone
  2. Aldosterone
  3. Atrial natriuretic peptide
  4. Antidiuretic hormone Correct answer.

Explanation

Antidiuretic hormone (vasopressin) is released from the posterior pituitary and increases water permeability of collecting duct cells by inserting aquaporin-2 channels. Aldosterone promotes sodium reabsorption; ANP promotes natriuresis; ACTH controls adrenal cortisol release.

Question 41Basic Human Anatomy, Physiology and General Pathology

Which plasma protein is present in the highest concentration and is chiefly responsible for maintaining plasma oncotic pressure?

  1. Albumin Correct answer.
  2. Fibrinogen
  3. Prothrombin
  4. Gamma globulin

Explanation

Albumin makes up roughly half of total plasma protein and exerts most of the colloid osmotic pressure that holds water within the capillaries. Its relatively small molecular size and high concentration allow it to oppose fluid loss into tissues.

Question 42Basic Human Anatomy, Physiology and General Pathology

Which blood vessel carries oxygenated blood from the lungs to the left atrium?

  1. Pulmonary artery
  2. Superior vena cava
  3. Aorta
  4. Pulmonary vein Correct answer.

Explanation

The pulmonary veins are the only veins that carry oxygenated blood, returning it from the alveolar capillaries to the left atrium. The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.

Question 43Basic Human Anatomy, Physiology and General Pathology

After a fibrin clot has formed, which blood component is chiefly responsible for clot retraction?

  1. Neutrophils
  2. Erythrocytes
  3. Lymphocytes
  4. Platelets Correct answer.

Explanation

Platelets contain actin and myosin and, after aggregating within the fibrin mesh, contract to shrink the clot and approximate wound edges. This platelet-mediated process is called clot retraction.

Question 44Basic Human Anatomy, Physiology and General Pathology

Which substance is almost completely reabsorbed in the proximal convoluted tubule under normal conditions?

  1. Glucose Correct answer.
  2. Hydrogen ion
  3. Urea
  4. Creatinine

Explanation

Glucose is reabsorbed in the proximal convoluted tubule by sodium-dependent cotransport, and normally all filtered glucose is recovered before the filtrate reaches the distal nephron. Urea and creatinine are largely retained in the filtrate, while hydrogen ions are secreted.

Question 45Basic Human Anatomy, Physiology and General Pathology

Which immunoglobulin class is the first antibody to appear in the circulation during a primary immune response?

  1. IgE
  2. IgG
  3. IgA
  4. IgM Correct answer.

Explanation

Naive B cells express IgM on their surface, and after antigenic stimulation they secrete IgM before class switching occurs. IgM is therefore the earliest circulating antibody in a primary response, whereas IgG predominates later.

Question 46Basic Human Anatomy, Physiology and General Pathology

Which vessels are the principal site of peripheral vascular resistance and therefore the main regulators of diastolic blood pressure?

  1. Arterioles Correct answer.
  2. Large elastic arteries
  3. Capillaries
  4. Large veins

Explanation

Arterioles have a relatively thick smooth muscle layer and a narrow lumen, so small changes in their diameter produce large changes in resistance. This allows them to regulate tissue blood flow and systemic arterial pressure.

Question 47Basic Human Anatomy, Physiology and General Pathology

A patient with severe prolonged vomiting is most likely to develop which acid-base and electrolyte disturbance?

  1. Metabolic alkalosis with hypokalaemia Correct answer.
  2. Metabolic acidosis with hyperkalaemia
  3. Respiratory alkalosis with hypokalaemia
  4. Respiratory acidosis with hyperkalaemia

Explanation

Vomiting causes loss of gastric hydrogen and chloride ions, producing a metabolic alkalosis, while loss of potassium-rich fluid and renal compensation lead to hypokalaemia. The resulting picture is classically a hypokalaemic, hypochloraemic metabolic alkalosis.

Question 48Basic Human Anatomy, Physiology and General Pathology

Which vitamin K-dependent clotting factor has the shortest plasma half-life and is therefore the earliest to fall after starting warfarin?

  1. Factor X
  2. Factor IX
  3. Factor VIII
  4. Factor VII Correct answer.

Explanation

Factors II, VII, IX and X are vitamin K dependent, but factor VII has the shortest half-life of about six hours. Its rapid decline explains why the prothrombin time lengthens before other vitamin K-dependent clotting tests become abnormal.

Question 49Basic Human Anatomy, Physiology and General Pathology

A patient with fever and renal failure has a blood film showing schistocytes, thrombocytopenia and a raised lactate dehydrogenase. Which process best explains these findings?

  1. Megaloblastic anaemia with pancytopenia
  2. Microangiopathic haemolytic anaemia Correct answer.
  3. Autoimmune haemolytic anaemia
  4. Iron-deficiency anaemia with thrombocytosis

Explanation

Schistocytes indicate red cells fragmented by fibrin strands in small vessels, the hallmark of microangiopathic haemolysis. Associated platelet consumption causes thrombocytopenia, and red cell destruction raises lactate dehydrogenase.

Question 50Basic Human Anatomy, Physiology and General Pathology

Which cells of the juxtaglomerular apparatus secrete renin in response to reduced renal perfusion?

  1. Macula densa cells
  2. Juxtaglomerular cells Correct answer.
  3. Podocytes
  4. Mesangial cells

Explanation

Juxtaglomerular cells are modified smooth muscle cells in the afferent arteriole that store and release renin when renal perfusion pressure falls. Renin then initiates the renin-angiotensin-aldosterone system to restore blood pressure and sodium balance.