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.
| 551. |
With respect to splanchnic circulation: |
| A. | the liver is approximately 50% blood by volume |
| B. | zone 3 of the hepatic acinus is well oxygenated |
| C. | abdominal viscera receive at 30% cardiac output |
| D. | liver receives blood from hepatic artery (1000???ml/min) and hepatic ??? vein (500ml/min) |
| E. | muscular layer of intestinal wall has higher flow of mucosal layer |
| Answer» D. liver receives blood from hepatic artery (1000???ml/min) and hepatic ??? vein (500ml/min) | |
| 552. |
Mesengial cell contraction is stimulated by: |
| A. | ANP |
| B. | dopamine |
| C. | PGE2 |
| D. | cAMP |
| E. | angiotensin II |
| Answer» F. | |
| 553. |
Regarding ventilation / perfusion (V/Q) relationships, which statement is INCORRECT? |
| A. | V/Q ratio is greatest at the lung apex |
| B. | V/Q ratio is about one at level of third rib when upright |
| C. | ventilation decreases proportionately more than perfusion from base to apex |
| D. | V/Q ratio for whole lung at rest is about 0.8 |
| E. | exercise increases the V/Q ratio |
| Answer» D. V/Q ratio for whole lung at rest is about 0.8 | |
| 554. |
Blood pressure: |
| A. | fluctuates in the aorta between 180 and 20mmHg |
| B. | is approaching 0mmHg at the right atrium |
| C. | is half in the pulmonary arteries of that in the aorta |
| D. | is greater in large veins than the vena cava |
| E. | drops significantly at capillary level |
| Answer» C. is half in the pulmonary arteries of that in the aorta | |
| 555. |
Regarding movement across cell membranes |
| A. | Exocytosis requires sodium and energy |
| B. | Insulin reuptake is by receptor mediated endocytosis |
| C. | Thyroid hormones decrease the activity of the NaK ATPase |
| D. | Active transport of sodium is rarely coupled with other substances |
| E. | NaK ATPase has a 1:1 coupling ratio |
| Answer» C. Thyroid hormones decrease the activity of the NaK ATPase | |
| 556. |
Which one of the following statements regarding ventilation is INCORRECT? |
| A. | tidal volume in the average human is 500ml |
| B. | anatomical dead space is the volume of the conducting airway and is about 160ml |
| C. | upper regions of the lung ventilate better than the lower regions |
| D. | you can measure physiological dead space via Bohr s method to get what is called a Bohr equation which is: VD PACO2-PECO2 VT PACO2 |
| E. | None of the above |
| Answer» D. you can measure physiological dead space via Bohr s method to get what is called a Bohr equation which is: VD PACO2-PECO2 VT PACO2 | |
| 557. |
Regarding neuromuscular transmission, which statement is INCORRECT? |
| A. | smooth muscle cells possess synapses en passant |
| B. | about 10 times as much acetylcholine as is required is released at skeletal muscle neuromuscular junctions |
| C. | antibodies can develop to calcium channels in nerve endings at neuromuscular junctions |
| D. | more than one nerve fibre ends on each end-plate in skeletal muscle |
| E. | acetylcholine is released by exocytosis |
| Answer» E. acetylcholine is released by exocytosis | |
| 558. |
Regarding temperature regulation, which is NOT true? |
| A. | the anterior hypothalamus contains temperature sensitive cells |
| B. | shivering is activated by the posterior hypothalamus |
| C. | the anterior hypothalamus controls mechanisms activated by heat |
| D. | horripilation acts to increase heat production |
| E. | fever is produced by the action of cytokines on the hypothalmus |
| Answer» F. | |
| 559. |
Regarding muscle spindles, which is NOT true? |
| A. | they contain nuclear bag and nuclear chain fibres |
| B. | they receive a motor supply via A fibres |
| C. | they discharge more upon stretching of the muscle |
| D. | they are responsible for the inverse stretch reflex |
| E. | they relay information to the cord via Ia fibres |
| Answer» E. they relay information to the cord via Ia fibres | |
| 560. |
Which of the following DOES NOT decrease lung compliance? |
| A. | left ventricular failure |
| B. | atelectasis |
| C. | pulmonary fibrosis |
| D. | advancing age |
| E. | raised pulmonary capillary wedge pressure |
| Answer» E. raised pulmonary capillary wedge pressure | |
| 561. |
Which statement regarding glucagon is INCORRECT? |
| A. | it is used as an antidote in symptomatic beta blocker overdosage |
| B. | it is synthesised in the A cells of the pancreatic islets and in small intestinal mucosal cells |
| C. | its major site of metabolism is in the plasma |
| D. | it is synthesised in common with glicentin |
| E. | the exogenous glucagon is associated with nausea and vomiting |
| Answer» D. it is synthesised in common with glicentin | |
| 562. |
Which of the following is NOT true regarding the voiding reflex? |
| A. | it involves parasympathetic fibres |
| B. | it remains intact in the period of spinal shock following transaction of the spinalcord |
| C. | it occurs when the bladder volume reaches 300-400mls |
| D. | it is integrated in the sacral segments of the spinal cord |
| E. | its threshold is altered by inhibitory fibres from the brainstem |
| Answer» C. it occurs when the bladder volume reaches 300-400mls | |
| 563. |
Regarding the lung volumes in a healthy 70kg male, 183cm tall, which is INCORRECT? |
| A. | tidal volume = 500ml |
| B. | residual volume = 1200ml |
| C. | expiratory reserve volume = 1000ml |
| D. | inspiratory capacity = 3300ml |
| E. | vital capacity = 4800ml |
| Answer» E. vital capacity = 4800ml | |
| 564. |
The emotional component to pain is due to activation of: |
| A. | post central gyrus |
| B. | sylvian fissure |
| C. | hippocampus |
| D. | cingulated cortex |
| E. | calcavine fissure |
| Answer» B. sylvian fissure | |
| 565. |
Regarding renal handling of potassium, which is INCORRECT? |
| A. | 10 to 15% of filtered load may be excreted in urine |
| B. | two potassium per sodium are reabsorbed in thick ascending limb |
| C. | excretion decreased in acidosis |
| D. | distal tubular secretion is capable of adaptation depending on demand |
| E. | aldosterone increases distal tubular secretion in exchange for sodium |
| Answer» C. excretion decreased in acidosis | |
| 566. |
Regarding protein metabolism: |
| A. | NH4 + is formed by reductive deamination of amino acids |
| B. | most of the body s urea is formed in the kidney |
| C. | phosphorylcreatine is formed in the liver |
| D. | creatinuria occurs normally in children |
| E. | purines and pyrimidines are mainly sourced from dietary intake |
| Answer» E. purines and pyrimidines are mainly sourced from dietary intake | |
| 567. |
Which statement regarding calcitonin is INCORRECT? |
| A. | it is secreted by parafollicular cells of the thyroid gland |
| B. | it inhibits osteoclastic bone resorption |
| C. | total thyroidectomy is usually associated with hypercalcaemia |
| D. | it decreases renal tubular calcium and phosphate reabsorption |
| E. | it is only secreted when plasma calcium concentration exceeds 9.5mg/100ml |
| Answer» D. it decreases renal tubular calcium and phosphate reabsorption | |
| 568. |
Regarding the actions of glucagon, which of the following is INCORRECT? |
| A. | it increases blood lactate level |
| B. | it activates hormone-sensitive lipase |
| C. | it has a positive inotropic effect on myocardium |
| D. | large amounts cause intestinal relaxation |
| E. | it decreases renal tubular sodium reabsorption |
| Answer» B. it activates hormone-sensitive lipase | |
| 569. |
With respect to the ascending pathways of sensation within the spinal cord: |
| A. | the ??? columns connect with the medial branches (crosses midline) |
| B. | the central spinothalamic tract carries pain/temp fibres |
| C. | the lateral spinothalamic tract has small fibres medially |
| D. | gracile fasiculatus contains fibres from thoracic and cervical nerves |
| E. | proprioception is transmitted in the lateral spinothalamic tract |
| Answer» B. the central spinothalamic tract carries pain/temp fibres | |
| 570. |
Regarding pulmonary function, which of the following is NOT true? |
| A. | FRC = ERV + RV |
| B. | IRV in men is about 3,3L |
| C. | RV in women is about 1.1L |
| D. | inspiratory capacity in men = 4.8L |
| E. | total lung capacity = 6L in men, 4.2L in women |
| Answer» E. total lung capacity = 6L in men, 4.2L in women | |
| 571. |
Which of the following is most susceptible to pressure? |
| A. | group A motor |
| B. | group C |
| C. | group B |
| D. | pre ganglionic-autonomic |
| E. | muscle spindle fibres |
| Answer» B. group C | |
| 572. |
Regarding pulmonary perfusion, which statement is INCORRECT? |
| A. | apical perfusion is less than basal |
| B. | E.coli endotoxin causes venodilatation |
| C. | total pulmonary blood flow increases 3-6 fold during exercise |
| D. | pulmonary vascular resistance increases at small lung volumes |
| E. | in zone 2, pulmonary arterial pressure is greater than alveolar pressure |
| Answer» C. total pulmonary blood flow increases 3-6 fold during exercise | |
| 573. |
Timing of events in the cardiac cycle: |
| A. | right atrial systole begins after left atrial systole |
| B. | the pulmonary closes after the aortic in inspiration |
| C. | right ventricular ejection starts after left ventricular ejection |
| D. | right ventricular systole starts after left ventricular systole |
| E. | right and left atrial systole are synchronous |
| Answer» C. right ventricular ejection starts after left ventricular ejection | |
| 574. |
Regarding pulmonary ventilation, which statement is INCORRECT? |
| A. | physiological dead space is normally larger than anatomical dead space |
| B. | basal ventilation is greater than apical |
| C. | normal tide volume is about 7ml/kg |
| D. | airway resistance decreases at large lung volumes |
| E. | total pulmonary ventilation can increase by up to 20 fold during exercise |
| Answer» B. basal ventilation is greater than apical | |
| 575. |
Regarding functional morphology of the cell |
| A. | Tay Sachs disease is a cell membrane disorder |
| B. | Actin is the most abundant protein in mammalian cells |
| C. | Peroxisomes are 5 um in diameter |
| D. | The assembly of microtubules in the cell cytoskeleton is facilitated by cold |
| E. | Myosin 1 is present in skeletal muscle |
| Answer» C. Peroxisomes are 5 um in diameter | |
| 576. |
The action potential: |
| A. | is always monophasic |
| B. | has an absolute refractory period lasting to the start of the after depolarisation |
| C. | has a relative refractory period lasting until repolarisation is complete |
| D. | requires opening of voltage gated Na+ channels |
| E. | results in K+ conductance |
| Answer» E. results in K+ conductance | |
| 577. |
Which of the following DOES NOT constrict pulmonary arterioles? |
| A. | adrenaline |
| B. | thromboxane B2 |
| C. | noradrenaline |
| D. | prostaglandin F2 |
| E. | isoproteronol |
| Answer» F. | |
| 578. |
Mean pressure (mmHg) in the main pulmonary artery is: |
| A. | 2 |
| B. | 5 |
| C. | 8 |
| D. | 15 |
| E. | 25 |
| Answer» E. 25 | |
| 579. |
Which of the following substances is NOT removed from the blood by the lung? |
| A. | prostaglandins |
| B. | noradrenaline |
| C. | acetylcholine |
| D. | adrenaline |
| E. | bradykinin |
| Answer» E. bradykinin | |
| 580. |
Which of the following substances is NOT synthesised by the lung? |
| A. | prostaglandins |
| B. | serotonin |
| C. | dipalmityl phosphatidylcholine |
| D. | histamine |
| E. | kallikrein |
| Answer» C. dipalmityl phosphatidylcholine | |
| 581. |
Glucagon levels are increased by: |
| A. | secretin |
| B. | somatostatin |
| C. | cholecystokinin |
| D. | free fatty acids |
| E. | ketones |
| Answer» D. free fatty acids | |
| 582. |
Regarding pain transmission, which is NOT true? |
| A. | fast pain fibres are A fibres |
| B. | slow pain fibres are C fibres |
| C. | substance P is the central transmitter |
| D. | all impulses pass through the central horn |
| E. | pain sensation results from over-stimulation of other sensory modalities |
| Answer» F. | |
| 583. |
Regarding the renin-angiotensin system, which is CORRECT? |
| A. | renin has many functions including the formation of angiotensin I from angiotensinogen |
| B. | after nephrectomy, circulating levels of prorenin fall |
| C. | renin is formed in the juxtaglomerular cells of the kidney |
| D. | active renin has a half-life in the circulation of 40 minutes or less |
| E. | prorenin is biologically active |
| Answer» D. active renin has a half-life in the circulation of 40 minutes or less | |
| 584. |
Regarding vitamin D metabolism: |
| A. | 25-hydroxycholecalciferol is converted to 1,25-dihydroxycholecalciferol in the distal convoluted tubule of the kidney |
| B. | 1,25-dihydroxycholecalciferol receptors can be found in skin |
| C. | when calcium levels are high, 24,25-dihydroxycholecalciferol levels are also high |
| D. | transport in plasma is by binding to haemoglobin |
| E. | formation of 25-hydroxycholecalciferol is tightly regulated |
| Answer» C. when calcium levels are high, 24,25-dihydroxycholecalciferol levels are also high | |
| 585. |
Which of the following nerve fibre types has the LEAST myelin? |
| A. | A-alpha |
| B. | A-beta |
| C. | A-gamma |
| D. | B |
| E. | C |
| Answer» F. | |
| 586. |
Calcitonin secretion is stimulated by the following EXCEPT: |
| A. | gastrin |
| B. | somatostatin |
| C. | oestrogen |
| D. | cholecystokinin |
| E. | glucagon |
| Answer» C. oestrogen | |
| 587. |
With reference to the action potential: |
| A. | decreasing the external Na+ concentration increases the size of the action potential |
| B. | decreasing the external K+ concentration decreases the resting membrane potential |
| C. | increasing the external Na+ concentration decreases the resting membrane potential |
| D. | decreasing the external K+ concentration has little effect on the resting membrane potential |
| E. | none of the above are true |
| Answer» F. | |
| 588. |
Regarding renal handling of calcium, which is INCORRECT? |
| A. | metabolic acidosis decreases reabsorption |
| B. | growth hormone increases reabsorption |
| C. | calcium is actively reabsorbed |
| D. | about 60% of filtered calcium load is reabsorbed in proximal tubules |
| E. | glucocorticoids increase calcium reabsorption |
| Answer» C. calcium is actively reabsorbed | |
| 589. |
Which nerve fibre is MOST susceptible to local anaesthetics? |
| A. | proprioception |
| B. | touch |
| C. | motor to muscle spindles |
| D. | somatic motor |
| E. | dorsal root pain and temperature |
| Answer» F. | |
| 590. |
Which of the following nerve fibre types is MOST sensitive to local anaesthetic blockade? |
| A. | A-alpha |
| B. | A-gamma |
| C. | A-delta |
| D. | B |
| E. | C |
| Answer» F. | |
| 591. |
The action potential of a neuron (influx): |
| A. | is initiated by efflux of Na+ |
| B. | is terminated by efflux of K+ |
| C. | declines in amplitude as it moves along the axon |
| D. | results in transient reversal of the concentration (?electrical) gradient of Na+ across the cell membrane |
| E. | is not associated with any net movement of Na+ of K+ across the cell membrane |
| Answer» F. | |
| 592. |
What percentage of cardiac output goes to the kidneys at rest? |
| A. | 10% |
| B. | 15% |
| C. | 25% |
| D. | 35% |
| E. | 45% |
| Answer» D. 35% | |
| 593. |
In compensated low output cardiac failure: |
| A. | venous resistance is decreased |
| B. | cardiac contractility is increased |
| C. | mean systemic filling pressure is decreased |
| D. | right atrial pressure is decreased |
| E. | venous return is decreased |
| Answer» E. venous return is decreased | |
| 594. |
With respect to nerve fibre types: |
| A. | the speed on conduction is inversely proportional to the diameter of the fibre |
| B. | C fibres are more susceptible to local anaesthetics than A fibres |
| C. | A fibres are concerned primarily with somatic motor function |
| D. | pain may be relayed by all fibre types |
| E. | A fibres are efferent only |
| Answer» C. A fibres are concerned primarily with somatic motor function | |
| 595. |
Regarding pulmonary blood flow: |
| A. | increased arterial pressure leads to increased pulmonary vascular resistance |
| B. | localised vasoconstriction is directly due to arterial PO2 hypoxia |
| C. | regional differences are due to hydrostatic pressure differences |
| D. | at the apex Pa>Pv>PA |
| E. | pulmonary arteries and veins have transmural pressures equal to alveolar pressure |
| Answer» D. at the apex Pa>Pv>PA | |
| 596. |
Regarding the kidney and urine formation: |
| A. | specific gravity is measure of osmolality |
| B. | thin ascending limb relatively impermeable to water |
| C. | thin ascending limb relatively impermeable to Na+ Cl- |
| D. | water diuresis begins about 1 hour after ingestion of a water load |
| E. | high protein diet does not affect concentrating ability of kidney |
| Answer» C. thin ascending limb relatively impermeable to Na+ Cl- | |
| 597. |
Functional anatomy of the kidney which is TRUE? |
| A. | 5 million nephrons in each human kidney |
| B. | pores in terestrated kidneys are 170-190nm in diameter |
| C. | mesengial cells are located between the basal lumina and podocytes |
| D. | glomerular membrane permits passage of small (???) neutral substances |
| E. | proximal tubule is 100nm long |
| Answer» E. proximal tubule is 100nm long | |
| 598. |
Which of the following substances is not excreted by the kidney in a normal adult on an average diet? |
| A. | K+ |
| B. | uric acid |
| C. | creatinine |
| D. | glucose |
| E. | urea |
| Answer» E. urea | |
| 599. |
Functional anatomy of the kidney which is FALSE? |
| A. | total length of the nephrons ranges from 45-65mm |
| B. | the macula densa is ??? tubular epithelium of the collecting duct |
| C. | juxtaglomerular cells are found in the walls of the different arteriole |
| D. | intercolated cells are involved in acid secretion and bicarbonate transport |
| E. | total glomerular capillary endothelium across which filtration occurs, is 0.8m2 |
| Answer» C. juxtaglomerular cells are found in the walls of the different arteriole | |
| 600. |
Glucagon increases the secretion of all of the following EXCEPT: |
| A. | catecholamines from a phaeochromocytoma |
| B. | atrial natriuretic peptide |
| C. | growth hormone |
| D. | insulin |
| E. | calcitonin from a medullary carcinoma of the thyroid |
| Answer» C. growth hormone | |