MCQOPTIONS
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MCQOPTIONS
This section includes 697 Mcqs, each offering curated multiple-choice questions to sharpen your Biology knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Regarding ECG changes, which is CORRECT? |
| A. | hypernatraemia is associated with low voltage complexes |
| B. | the first change in hyperkalaemia is prolongation of QRS |
| C. | with hypokalaemia, the resting membrane potential decreases |
| D. | in hyperkalaemia, the heart stops in systole |
| E. | in hypercalcaemia, myocardial contractility is enhanced |
| Answer» F. | |
| 2. |
Regarding jugular pressure waves: |
| A. | the v wave denotes the increased atrial pressure due to the bulging of the tricuspid valve during isovolumetric ventricular contraction |
| B. | in tricuspid insufficiency, there is a giant A wave with each ventricular systole |
| C. | atrial premature beats produce an A wave |
| D. | the v wave occurs during systole |
| E. | a giant C wave ( cannon wave ) may be seen in complete heart block |
| Answer» D. the v wave occurs during systole | |
| 3. |
What factor does not alter cardiac output? |
| A. | standing up |
| B. | sleeping |
| C. | eating |
| D. | exercising |
| E. | pregnancy |
| Answer» C. eating | |
| 4. |
What is the O2 consumption of a beating heart at rest? |
| A. | 2ml/100g/min |
| B. | 9ml/g/min |
| C. | 2ml/g/min |
| D. | 2L/100g/min |
| E. | 9ml/100g/min |
| Answer» F. | |
| 5. |
Regarding percentages of blood volume in the body: |
| A. | the heart has 5% |
| B. | the pulmonary circulation has the greatest percentage |
| C. | the venous circulation has 35% |
| D. | the aorta has 2% |
| E. | capillaries have 20% |
| Answer» E. capillaries have 20% | |
| 6. |
What is a biological action of endothelin? |
| A. | dilates vascular smooth muscle |
| B. | produces bronchodilation |
| C. | increase GFR and renal blood flow |
| D. | evokes positive inotropic and chronotropic effects on myocardium |
| E. | inhibits gluconeogenesis |
| Answer» E. inhibits gluconeogenesis | |
| 7. |
What inhibits gene transcription for endothelin-1 secretion: |
| A. | nitric oxide |
| B. | angiotensin II |
| C. | insulin |
| D. | growth factors |
| E. | catecholamines |
| Answer» B. angiotensin II | |
| 8. |
Regarding NO synthase: |
| A. | it synthesises nitrous oxide from arginine |
| B. | there are 2 isoforms |
| C. | it is inactivated by haemoglobin |
| D. | NOS-1 is activated by cytokines |
| E. | NOS-2 is in endothelial cells |
| Answer» D. NOS-1 is activated by cytokines | |
| 9. |
Which is NOT a baroreceptor site? |
| A. | right atria at the entrance of SVC and IVC |
| B. | aortic arch |
| C. | left atria at the entrance of the pulmonary veins |
| D. | pulmonary circulation |
| E. | carotid body |
| Answer» F. | |
| 10. |
Regarding cerebrospinal fluid: |
| A. | the total volume of CSF is 300mL |
| B. | CSF is absorbed through the choroid plexus |
| C. | the average CSF pressure is 220m-CSF |
| D. | CSF has a higher pH than plasma |
| E. | it contains very low levels of cholesterol relative to plasma |
| Answer» F. | |
| 11. |
Which substance has equal concentrations in CSF and plasma? |
| A. | Ca2+ |
| B. | K+ |
| C. | Na+ |
| D. | PCO2 |
| E. | glucose |
| Answer» D. PCO2 | |
| 12. |
What factor dilates the arterioles? |
| A. | decreased local temperature |
| B. | myogenic theory of autoregulation |
| C. | angiotensin II |
| D. | increased discharge of noradrenergic vasomotor nerve |
| E. | histamine |
| Answer» F. | |
| 13. |
Which vessel has the lowest PO2? |
| A. | maternal artery |
| B. | maternal vein |
| C. | uterine vein |
| D. | umbilical vein |
| E. | umbilical artery |
| Answer» F. | |
| 14. |
Atrial systole: |
| A. | causes a decrease in atrial pressure |
| B. | causes the A wave of the jugular pulse |
| C. | causes the C wave of the jugular pulse |
| D. | causes the V wave of the jugular pulse |
| E. | causes the dicrotic notch of the aortic pulse |
| Answer» C. causes the C wave of the jugular pulse | |
| 15. |
During exercise: |
| A. | diastolic BP increases more than systolic BP |
| B. | regional blood flow to the brain doubles |
| C. | cardiac output may increase 15-fold |
| D. | after exercise, BP takes longer to return to normal than heart rate |
| E. | O2 consumption of skeletal muscle may increase 100-fold |
| Answer» F. | |
| 16. |
Regarding cardiac electrical properties: |
| A. | all cardiac cells have the same resting membrane potential |
| B. | cholinergic fibres act predominantly by blocking tonic sympathetic input |
| C. | discharge rates of pacemaker tissue does not change significantly with temperature |
| D. | the bundle of HIS is not the most rapidly conducting part of the conducting system |
| E. | the last parts of myocardium to depolarise normally do not include the septum |
| Answer» E. the last parts of myocardium to depolarise normally do not include the septum | |
| 17. |
The depolarisation of cardiac muscle cells is characterised by: |
| A. | a slow depolarisation, a plateau then a rapid repolarisation |
| B. | initial depolarisation due to a slow Na+ influx |
| C. | repolarisation due to K+ efflux through two types of K+ channels |
| D. | a plateau phase due to slowly opening Na+ channels |
| E. | calcium efflux during the plateau phase |
| Answer» E. calcium efflux during the plateau phase | |
| 18. |
Features of the venous system include all of the following EXCEPT: |
| A. | total volume is approximately 55% of the total vascular volume |
| B. | compliance approximately 25 times the arterial side |
| C. | total volume of venules is twice the total capillary volume |
| D. | valves in the cerebral circulation |
| E. | substantial venoconstriction in response to noradrenaline |
| Answer» E. substantial venoconstriction in response to noradrenaline | |
| 19. |
Abnormalities causing ECG changes in myocardial infarction include: |
| A. | delayed repolarisation early on |
| B. | delayed depolarisation |
| C. | increased resting membrane potential |
| D. | TQ segment elevation |
| E. | current flow away from the infarct |
| Answer» C. increased resting membrane potential | |
| 20. |
Regarding the inputs into the vasomotor centre: |
| A. | baroreceptors causes stimulation |
| B. | chemoreceptors cause inhibition |
| C. | baroreceptors provide significant input below 70mmhg mean arterial pressure |
| D. | atrial stretch receptors inhibit the vasomotor centre |
| E. | direct inputs include pO2 |
| Answer» E. direct inputs include pO2 | |
| 21. |
Arteriolar constriction is caused by: |
| A. | serotonin |
| B. | ANP |
| C. | NO |
| D. | K+ |
| E. | histamine |
| Answer» B. ANP | |
| 22. |
CSF: |
| A. | volume is about 600ml |
| B. | normal pressure is 5-10cm CSF |
| C. | has a higher concentration of creatinine than plasma |
| D. | has a higher concentration of urea than plasma |
| E. | is formed solely in the choroid plexus |
| Answer» D. has a higher concentration of urea than plasma | |
| 23. |
During systole: |
| A. | the peak left ventricular pressure is 160mmHg |
| B. | contraction of the atria propels 70% of the ventricular filling |
| C. | the period of isovolumetric ventricular contraction is 0.5sec???? |
| D. | the end systolic ventricular volume is about 50mL |
| E. | coronary blood flow to subendocardial portions of the left ventricle occur only in systole |
| Answer» E. coronary blood flow to subendocardial portions of the left ventricle occur only in systole | |
| 24. |
Regarding the conduction system of the heart: |
| A. | the right bundle branch (of HIS) divides into anterior and posterior fasicles |
| B. | the AV node contains P cells |
| C. | myocardial fibres have a resting membrane potential of -60mV |
| D. | action potential in the SA and AV nodes are largely due to Na+ influx |
| E. | there are two types of K+ channels in pacemaker tissue transient and long acting |
| Answer» C. myocardial fibres have a resting membrane potential of -60mV | |
| 25. |
Regarding cardiac output: |
| A. | energy of contraction is proportional to the initial length of the cardiac muscle fibre is Fick s Law of the heart |
| B. | cardiac index is the correlation between resting cardiac output and height |
| C. | sleep decreases cardiac output |
| D. | basal O2 consumption by the myocardium is 2ml/g/min |
| E. | standing normally decreases the length of ventricular cardiac muscle fibres |
| Answer» F. | |
| 26. |
Regarding surfactant, which statement is INCORRECT? |
| A. | it predominantly consists of phospholipid |
| B. | it is increased by long-term 100% oxygen therapy |
| C. | hydrophobic tails face into alveolar lumen |
| D. | it is decreased by cigarette smoking |
| E. | pulmonary oedema is a consequence of its absence |
| Answer» C. hydrophobic tails face into alveolar lumen | |
| 27. |
Regarding renal handling of substances: |
| A. | urea is filtered, but not secreted |
| B. | most sodium is resorbed in the loop of Henle |
| C. | creatinine is not filtered, but is resorbed |
| D. | potassium is filtered, but not secreted |
| E. | chloride is secreted and resorbed |
| Answer» B. most sodium is resorbed in the loop of Henle | |
| 28. |
Regarding nephrons permeability: |
| A. | glomerular capillaries are 100 times more permeable than skeletal muscle capillaries |
| B. | anionic substances are more permeable than neutral substances |
| C. | N (?normal) glomerular concentration of albumin is 0.2% of plasma concentration |
| D. | neutral substances are freely filtered with diameters < 8nm |
| E. | 100mg/d of protein is filtered at the glomerulus |
| Answer» D. neutral substances are freely filtered with diameters < 8nm | |
| 29. |
Where is the macula densa located? |
| A. | afferent arteriole |
| B. | efferent arteriole |
| C. | proximal convoluted tubule |
| D. | thick ascending limb of loop of Henle |
| E. | distal convoluted tubule |
| Answer» E. distal convoluted tubule | |
| 30. |
Triiodothyronine: |
| A. | is less potent than thyroxine |
| B. | deficiency causes yellow skin due to keratin buildup |
| C. | acts via a tyrosine kinase predominantly |
| D. | causes an increase in Na+ /K+ ATPase activity |
| E. | in both, deficiency but no excess leads to muscle weakness |
| Answer» F. | |
| 31. |
The amount of O2 in blood with a PaO2 of 100mmHg is: |
| A. | 0.003ml O2/100ml |
| B. | 0.3ml O2/100ml |
| C. | 3ml O2/100ml |
| D. | 3ml O2/mL |
| E. | 0.3ml O2/L |
| Answer» C. 3ml O2/100ml | |
| 32. |
Regarding surfactant: |
| A. | infant respiratory distress syndrome can be adequately treated with administration of phospholipids alone |
| B. | cigarette smokers have the same amount of surfactant as non-smokers |
| C. | the phospholipid film is formed by tubular myelin |
| D. | infant respiratory distress syndrome is caused by insufficient surfactant that prevents the alveoli from expanding at first inspiratory effort |
| E. | formation of the phospholipid film is greatly facilitated by the carbohydrate in surfactant |
| Answer» D. infant respiratory distress syndrome is caused by insufficient surfactant that prevents the alveoli from expanding at first inspiratory effort | |
| 33. |
Which abolishes automatic respiration? Destruction of: |
| A. | pre-Bottzinger complexes |
| B. | ventral gp respiratory neurons |
| C. | dorsal gp respiratory neurons |
| D. | section at the inferior border of the pons |
| E. | transaction rostral to the pons |
| Answer» B. ventral gp respiratory neurons | |
| 34. |
Normally the FEV1 is what percentage of FVC? |
| A. | 50% |
| B. | 60% |
| C. | 70% |
| D. | 80% |
| E. | 90% |
| Answer» E. 90% | |
| 35. |
Regarding the glottis: |
| A. | when laryngeal adductors are paralysed there is inspiratory stridor |
| B. | abductors contract early in inspiration |
| C. | when abductors are paralysed, aspiration pneumonia may result |
| D. | the adductors are supplied by the vagus nerves, the abduction by the hypoglossal nerve |
| E. | in animals with bilateral cervical vagotomy, pulmonary oedema is purely secondary to aspiration |
| Answer» C. when abductors are paralysed, aspiration pneumonia may result | |
| 36. |
Myosin binding sites on actin are normally covered by: |
| A. | troponin I |
| B. | troponin C |
| C. | troponin T |
| D. | tropomyosin |
| E. | ryanodine molecule |
| Answer» E. ryanodine molecule | |
| 37. |
Why is NSAIDs use a relative contraindication in patients with chronic renal failure? |
| A. | direct toxic effects on proximal tubule |
| B. | direct toxic effects on collecting ducts |
| C. | indirect toxic effects on loop of Henle |
| D. | inhibition of prostaglandin synthesis which is an important regulator of renal blood flow in arterioles |
| E. | inhibition of prostaglandin synthesis which is an important regulator of renal blood flow in main renal arteries |
| Answer» E. inhibition of prostaglandin synthesis which is an important regulator of renal blood flow in main renal arteries | |
| 38. |
Noradrenaline: |
| A. | is the main neurotransmitter of the parasympathetic nervous system |
| B. | acts as sympathetic neuromuscular junctions in skeletal muscle and vascular smooth muscle |
| C. | is secreted by the adrenal medulla |
| D. | causes pupillary constriction |
| E. | reduces blood pressure |
| Answer» D. causes pupillary constriction | |
| 39. |
Carbonic anhydrase is not inhibited by: |
| A. | cyanide |
| B. | zinc |
| C. | azide |
| D. | sulphide |
| E. | collecting duct |
| Answer» C. azide | |
| 40. |
The reticular activating system: |
| A. | has depressed conduction during anaesthesia |
| B. | is located in the pons |
| C. | is a simple collection of parallel nerve fibres |
| D. | has no input from the cranial nerves |
| E. | is electrically isolated from the cerebral cortex |
| Answer» B. is located in the pons | |
| 41. |
Regarding thermoceptors: |
| A. | there are more warm receptors than cold receptors |
| B. | cold receptors respond to 10-38 C |
| C. | afferents for cold receptors are C fibres only |
| D. | afferents found in the ventral spinothalamic tract |
| E. | respond to the temperature gradient across the skin |
| Answer» D. afferents found in the ventral spinothalamic tract | |
| 42. |
Regarding rods and cones: |
| A. | Na+ channels are closed in the dark |
| B. | light striking the outer segments results in a depolarising receptor potential |
| C. | the receptor potentials are all-or-nothing |
| D. | rhodopsin is a serpentine receptor |
| E. | acetylcholine is released from the synaptic terminal |
| Answer» D. rhodopsin is a serpentine receptor | |
| 43. |
Regarding neurotoxins, which statement is INCORRECT? |
| A. | tetrodotoxin is a sodium channel blocker |
| B. | tetraethylammonium is a potassium channel blocker |
| C. | tetanospasmin interferes with GABA release |
| D. | botulinum toxin blocks release of acetylcholine |
| E. | latrotoxin causes explosive release of acetylcholine |
| Answer» D. botulinum toxin blocks release of acetylcholine | |
| 44. |
Acetylcholine: |
| A. | is a major neurotransmitter in the spinal cord |
| B. | is degraded within the neuromuscular end-plate by dehydration |
| C. | is important in the stimulation of pancreatic function |
| D. | is the neurotransmitter involved in vagal stimulation of the heart |
| E. | is antagonised by neostigmine |
| Answer» D. is the neurotransmitter involved in vagal stimulation of the heart | |
| 45. |
A motor unit is made up of: |
| A. | a flexor muscle and an extensor muscle |
| B. | a single skeletal muscle and all the motor neurons that supply it |
| C. | a single motor neuron and all the muscle fibres it innervates |
| D. | a large bundle of muscle fibres |
| E. | all the motor neurons in which responses are observed after maximal stimulation |
| Answer» D. a large bundle of muscle fibres | |
| 46. |
In skeletal muscle: |
| A. | thick filaments which are made up of myosin and tropomyosin are lined up to form A bands |
| B. | the dark A band has a light H band in its centre which in turn has an M line in its middle |
| C. | think filaments are made up of actin, tropomyosin and troponin and form the H band |
| D. | Z lines are connected to the thick filaments |
| E. | during contraction, the width of the A band reduces |
| Answer» D. Z lines are connected to the thick filaments | |
| 47. |
Microglia: |
| A. | are involved with myelin production |
| B. | are scavenger cells |
| C. | are performed in the brain |
| D. | are important in GABA uptake |
| E. | induce capillaries to form tight junctions and thus the blood brain barrier |
| Answer» C. are performed in the brain | |
| 48. |
Regarding denervation: |
| A. | it causes skeletal muscle hypertrophy |
| B. | does not lead to fibrillation |
| C. | causes hyposensitivity to acetylcholine in skeletal muscle |
| D. | smooth muscle is able to contract if it occurs in vivo |
| E. | causes fasciculations |
| Answer» E. causes fasciculations | |
| 49. |
Regarding decerebration: |
| A. | decerebration produces spinal shock |
| B. | decerebrate rigidity is spasticity due to diffuse facilitation of stretch reflex |
| C. | there is increased rate of discharge in the afferent neurons |
| D. | spasticity produced by decerebration is more marked in flexor muscles |
| E. | most commonly produces upper limb flexion and lower limb extension |
| Answer» C. there is increased rate of discharge in the afferent neurons | |
| 50. |
A sarcomere: |
| A. | contains two separate halves of an A-band and an I-band |
| B. | is the space between two A-bands |
| C. | is between two Z-lines |
| D. | has the T-system of the sarcotubular system at sarcomere junctions |
| E. | contracts when the troponin molecule binds to the myosin head |
| Answer» D. has the T-system of the sarcotubular system at sarcomere junctions | |