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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.
| 451. |
Characteristics of a substance suitable for measuring GFR do NOT include: |
| A. | freely filtered |
| B. | not toxic |
| C. | no effect on filtration rate |
| D. | not metabolised |
| E. | of low molecular weight |
| Answer» F. | |
| 452. |
Which of these factors do NOT affect GFR? |
| A. | renal blood flow |
| B. | ureteral obstruction |
| C. | dehydration |
| D. | a neutral molecule measuring 4 manometer |
| E. | angiotensin II effects on mesangial cells |
| Answer» E. angiotensin II effects on mesangial cells | |
| 453. |
Which site of diuretic action is INCORRECT? |
| A. | antidiuretic hormone antagonists act in collecting duct |
| B. | loop agents act in thin ascending limb |
| C. | carbonic anhydrase inhibitors act in proximal tubule |
| D. | thiazides act in early distal tubule |
| E. | aldosterone antagonists act in cortical collecting tubule |
| Answer» C. carbonic anhydrase inhibitors act in proximal tubule | |
| 454. |
Regarding bronchial tone: |
| A. | substance P causes bronchoconstriction |
| B. | constriction is caused by sympathetic discharge |
| C. | dilation is caused by parasympathetic discharge |
| D. | maximal bronchoconstriction occurs at 4am |
| E. | VIP causes bronchoconstriction |
| Answer» B. constriction is caused by sympathetic discharge | |
| 455. |
With regard to tuboglomerular feedback: |
| A. | the GFR increases when flow through the distal tubule increases |
| B. | the macula densa on the afferent arteriole is the sensor |
| C. | the afferent arteriole is constricted by thromboxane A2 |
| D. | it is designed to maintain Na+ reabsorption |
| E. | it does not operate in individual nephrons |
| Answer» D. it is designed to maintain Na+ reabsorption | |
| 456. |
The collecting duct is the main site of action for which of the following drugs? |
| A. | ethanol |
| B. | demeclocycline |
| C. | thiazide diuretics |
| D. | ethacrynic acid |
| E. | caffeine |
| Answer» C. thiazide diuretics | |
| 457. |
With regard to carbohydrate metabolism: |
| A. | the normal fasting glucose is from 3.9 to 11.0mmol/L |
| B. | glucose is phosphylated in cells to glucose-6-phosphate by phosphoenol-pyrunate carboxykinase |
| C. | glycogen, the storage form of glucose, is only in the liver and skeletal muscle |
| D. | glucose can be converted to fats through acetyl CoA which is irreversible |
| E. | none of the above |
| Answer» E. none of the above | |
| 458. |
Which is NOT present in high concentrations, at the active zone of synapses? |
| A. | syntaxin |
| B. | catecholamine vesicles |
| C. | neuropeptide vesicles |
| D. | synaptobrevin |
| E. | calcium channels |
| Answer» D. synaptobrevin | |
| 459. |
Regarding the chemical control of breathing, which statement is INCORRECT? |
| A. | central chemoreceptors are located in the medulla oblongata |
| B. | hypoxia makes an individual more sensitive to increases in arterial carbon dioxide |
| C. | arterial oxygen less than 70mmHg markedly stimulates respiration via the carotid bodies |
| D. | carotid bodies have the highest blood flow, per unit time per 100g, of any tissue in the body |
| E. | carbon dioxide is more important than oxygen in respiratory control |
| Answer» D. carotid bodies have the highest blood flow, per unit time per 100g, of any tissue in the body | |
| 460. |
Regarding erythropoietin, which statement is INCORRECT? |
| A. | its secretion increases within minutes to hours in response to hypoxia |
| B. | it causes pro-erythroblasts to mature more rapidly into erythrocytes |
| C. | the spleen and salivary glands secrete, but don t synthesise it |
| D. | it inhibits apoptosis in erythroid stem cells |
| E. | the adult liver is able to synthesise enough for normal erythropoiesis in the absence of both kidneys |
| Answer» F. | |
| 461. |
Regarding the work of breathing during quiet inspiration: |
| A. | elastic work = 80% |
| B. | viscous resistance = 7% |
| C. | airway resistance = 13% |
| D. | when tidal volume versus intrapleural pressure in quiet inspiration are plotted, a straight line results |
| E. | the amount of elastic work required to inflate the whole respiratory system is more than the amount required to inflate the lungs alone |
| Answer» C. airway resistance = 13% | |
| 462. |
Effective renal plasma flow is best measured using: |
| A. | inulin |
| B. | glucose |
| C. | PAH |
| D. | urea |
| E. | creatinine |
| Answer» D. urea | |
| 463. |
Regarding flow in vessels: |
| A. | velocity is greatest closest to blood vessel walls |
| B. | turbulence is almost always present at a Reynold s number greater than 2,000 |
| C. | probability of turbulence in a vessel is directly related to twice the radius |
| D. | flow in vessels is directly related to the fourth power of the ????? |
| E. | turbulence is related to increasing radius |
| Answer» D. flow in vessels is directly related to the fourth power of the ????? | |
| 464. |
Frusemide acts as a diuretic primarily by: |
| A. | inhibiting Na+ /K+ /Cl- co-transport in loop of Henle |
| B. | inhibiting action of vasopressin on collecting duct |
| C. | decreasing H+ secretion with resultant increase in Na+/K+ excretion |
| D. | inhibiting vasopressin secretion |
| E. | inhibiting Na+/K+ exchange in collecting ducts by inhibiting the action of aldosterone |
| Answer» B. inhibiting action of vasopressin on collecting duct | |
| 465. |
Saltatory conduction: |
| A. | only occurs in myelinated neurons |
| B. | is slower than non-saltatory conduction |
| C. | is unaffected by local anaesthetics |
| D. | does not occur with anti-dromic conduction |
| E. | is directly proportional in rate to the size of the action potential |
| Answer» B. is slower than non-saltatory conduction | |
| 466. |
Excitary amino acids in the brain are: |
| A. | glutamate and GABA |
| B. | GABA and glycine |
| C. | glutamate and glycine |
| D. | glycine and aspartate |
| E. | glutamate and aspartate |
| Answer» F. | |
| 467. |
The following vitamin is fat soluble: |
| A. | niacin |
| B. | B6 |
| C. | K |
| D. | pantothenic acid |
| E. | biotin |
| Answer» D. pantothenic acid | |
| 468. |
With respect to the counter current system: |
| A. | the loops of Henle act as counter current exchanges |
| B. | solutes diffuse out of vessels conducting blood towards the cortex |
| C. | water diffuses out of ascending vessels |
| D. | water diffuses into the collecting ducts |
| E. | counter current exchange is passive and can operate even if counter current multiplication ceases |
| Answer» C. water diffuses out of ascending vessels | |
| 469. |
Which of the following is NOT an action of somatostatin? |
| A. | it inhibits glucagon secretion |
| B. | it is a synaptic transmitter in the retina |
| C. | it inhibits insulin secretion |
| D. | it increases contraction of the gallbladder |
| E. | it inhibits pancreatic polypeptide secretion |
| Answer» E. it inhibits pancreatic polypeptide secretion | |
| 470. |
What increases GFR: |
| A. | moderate constriction of efferent arterioles |
| B. | moderate constriction of afferent arterioles |
| C. | increased Bowman s capsule pressure |
| D. | increased glomerular capillary osmotic pressure |
| E. | collecting duct |
| Answer» B. moderate constriction of afferent arterioles | |
| 471. |
What increases the anion gap: |
| A. | increased concentration of Mg2+ |
| B. | decreased concentration of plasma proteins |
| C. | decreased concentration of lactate |
| D. | increased concentration of ketoacids |
| E. | collecting duct |
| Answer» E. collecting duct | |
| 472. |
The major site of resistance in the bronchial tree is the: |
| A. | segmental bronchii |
| B. | medium-sized bronchii |
| C. | small bronchii |
| D. | large bronchioles |
| E. | terminal bronchioles |
| Answer» C. small bronchii | |
| 473. |
Site of most / major airway resistance is: |
| A. | trachea |
| B. | main bronchi |
| C. | large bronchi |
| D. | medium sized bronchi |
| E. | bronchioles |
| Answer» E. bronchioles | |
| 474. |
Which of the following DOES NOT shift the O2 dissociation curve to the right? |
| A. | increased temperature |
| B. | increased PCO2 |
| C. | increased H+ |
| D. | increased DPG |
| E. | increased carboxy haemoglobin |
| Answer» F. | |
| 475. |
Fick s law states that: |
| A. | Va = (VCO2/PCO2) x K |
| B. | V = (A.D.(P1 P2))/T |
| C. | pH - -LOG[H+] |
| D. | P1V1 = P2V2 |
| E. | V1/V2 = T1/2 |
| Answer» C. pH - -LOG[H+] | |
| 476. |
As urine flow increases during osmotic diuresis: |
| A. | the osmolality of urine falls |
| B. | the osmolality of urine increases |
| C. | the osmolality of urine approaches that of plasma |
| D. | the osmolality of urine is unchanged |
| E. | the osmolality of urine depends primarily on other factors |
| Answer» D. the osmolality of urine is unchanged | |
| 477. |
Regarding the O2 dissociation curve: |
| A. | O2 affinity of Hb is reduced when the curve is shifted to the left |
| B. | decreased 2,3-DPG shifts the curve to the right |
| C. | the Bohr effect is attributed to the action of PCO2 on H+ concentration |
| D. | temperature has no effect on the curve |
| E. | 2,3-DPG levels are reduced at altitude |
| Answer» D. temperature has no effect on the curve | |
| 478. |
Renal dose dopamine is: |
| A. | 1-2 mcg/kg/min |
| B. | 1-5 mcg/kg/min |
| C. | 1-10 mcg/kg/min |
| D. | 1-20 mcg/kg/min |
| E. | greater than 20 mcg/kg/min |
| Answer» E. greater than 20 mcg/kg/min | |
| 479. |
The glomerular filtration rate: |
| A. | is usually in the order of 125mL/min for an average healthy male |
| B. | is equal to the clearance of creatinine |
| C. | is indirectly related to filtration coefficient |
| D. | is determined by [urine]inulin |
| Answer» B. is equal to the clearance of creatinine | |
| 480. |
All of the following affect glomerular filtration, EXCEPT: |
| A. | changes in renal flood flow |
| B. | urethral obstruction |
| C. | dehydration |
| D. | oedema outside the renal capsule |
| E. | glomerular capillary permeability |
| Answer» E. glomerular capillary permeability | |
| 481. |
Human DNA what proportion codes for proteins? |
| A. | 3% |
| B. | 13% |
| C. | 23% |
| D. | 33% |
| E. | 53% |
| Answer» B. 13% | |
| 482. |
Glomerular filtration rate is best measured using: |
| A. | inulin |
| B. | glucose |
| C. | PAH |
| D. | urea |
| E. | creatinine |
| Answer» B. glucose | |
| 483. |
Regarding glomerular filtration: |
| A. | the glomerular filtration rate varies les than the renal plasma flow |
| B. | inulin is stored in the kidney |
| C. | sialoproteins in the glomerular capillary wall are positively charged |
| D. | dopamine causes contraction of mesangial cells |
| E. | changes in renal blood flow do not affect glomerular filtration rate |
| Answer» B. inulin is stored in the kidney | |
| 484. |
The calibre of extra-alveolar vessels is primarily determined by: |
| A. | the difference between alveolar pressure and the pressure within them |
| B. | the pressure in the pulmonary artery |
| C. | the lung volume |
| D. | the cardiac output |
| E. | the patient s fluid status |
| Answer» D. the cardiac output | |
| 485. |
Regarding synaptic structure / function: |
| A. | small clear vesicles in the presynaptic tunnel contain catecholamines |
| B. | tetanus toxin causes spastic paralysis by blocking release of ACh at NMJ |
| C. | chemical mediators located in ???? of presynaptic fibres contain one-way conduction of impulses |
| D. | the EPSP is an all-or-none response |
| E. | An I-PSP can be produced by localised increase in membrane permeability to Cl- |
| Answer» D. the EPSP is an all-or-none response | |
| 486. |
Action potentials: |
| A. | travel along neurons at a set velocity |
| B. | are only seen in neurons |
| C. | are generated initially by action of K+ voltage gated channels |
| D. | result from variation in Na+ and K+ membrane permeability |
| E. | are unidirectional impulses |
| Answer» E. are unidirectional impulses | |
| 487. |
A 15-year-old girl suffers from a malabsorption syndrome characterised by the malabsorption of fat. In which vitamin is she MOST likely to be deficient? |
| A. | niacin |
| B. | B6 |
| C. | K |
| D. | pantothenic acid |
| E. | biotin |
| Answer» D. pantothenic acid | |
| 488. |
Heart rate is accelerated by: |
| A. | decreased activity of baroreceptors in the left ventricle |
| B. | increased activity of baroreceptors in the pulmonary circulation |
| C. | increased intracranial pressure |
| D. | expiration |
| E. | increased activity of baroreceptors in the arteries |
| Answer» B. increased activity of baroreceptors in the pulmonary circulation | |
| 489. |
Starling s Law of the heart: |
| A. | is an example of hetermeric regulation |
| B. | is an example of homomeric regulation |
| C. | is explained by troponin / tropomyosin overlap |
| D. | relates stroke volume to cardiac output |
| E. | bears little relation to in vivo regulation of the heart |
| Answer» B. is an example of homomeric regulation | |
| 490. |
Which statement regarding gas exchange in the lungs is INCORRECT? |
| A. | gases generally cross by simple diffusion |
| B. | diffusion capacity for carbon dioxide is much greater than for oxygen |
| C. | nitrous oxide is a diffusion limited gas |
| D. | carbon monoxide does not reach equilibrium in 0.75 seconds |
| E. | oxygen is a perfusion limited gas |
| Answer» D. carbon monoxide does not reach equilibrium in 0.75 seconds | |
| 491. |
Halving the radius of an airway increases resistance: |
| A. | 2-fold |
| B. | 4-fold |
| C. | 8-fold |
| D. | 16-fold |
| E. | has no effect on resistance |
| Answer» E. has no effect on resistance | |
| 492. |
Which is not inactivated by the lungs? |
| A. | serotonin |
| B. | bradykinin |
| C. | leukotrienes |
| D. | prostaglandin E2 |
| E. | vasopressin |
| Answer» F. | |
| 493. |
Bitemporal hemianopia is most likely to be caused by a lesion at the: |
| A. | optic nerve |
| B. | optic chiasm |
| C. | optic tract |
| D. | optic radiation |
| E. | visual cortex |
| Answer» E. visual cortex | |
| 494. |
Regarding the alveolar gas equation: |
| A. | the respiratory quotient nears 1.0 with exercise |
| B. | PIO2= barometric pressure water vapour pressure |
| C. | PACO2 > PaCO2 |
| D. | PAO2 is normally 150mmHg |
| E. | remains valid if there is CO2 present in the inspired gas |
| Answer» B. PIO2= barometric pressure water vapour pressure | |
| 495. |
Ventilatory response to CO2 is reduced by all EXCEPT: |
| A. | sleep |
| B. | barbiturate overdose |
| C. | increasing age |
| D. | decreasing the work of breathing |
| E. | trained athletes and divers |
| Answer» E. trained athletes and divers | |
| 496. |
The ventilatory response to CO2 is increased by: |
| A. | sleep |
| B. | increasing age |
| C. | trained athlete |
| D. | morphine |
| E. | decreased PO2 |
| Answer» F. | |
| 497. |
Renal dose dopamine increases glomerular filtration rate by: |
| A. | dilating the renal arteries |
| B. | dilating the vasa recta |
| C. | constricting the efferent arteriole |
| D. | relaxing glomerular perivascular mesangial cells |
| E. | all of the above |
| Answer» E. all of the above | |
| 498. |
With respect to renal handling of glucose: |
| A. | glucose is reabsorbed from within the distal tubule by co-transport |
| B. | glucose is reabsorbed from within the proximal tubule by facilitated diffusion |
| C. | glucose is always completely reabsorbed |
| D. | movement of glucose from tubular epithelial cells is by passive diffusion |
| E. | none of the above |
| Answer» F. | |
| 499. |
Regarding alveolar cells, which statement is INCORRECT? |
| A. | type I pneumocytes repair alveolar epithelium |
| B. | pulmonary alveolar macrophages are derived from blood monocytes |
| C. | mast cell membranes bind IgE via Fc portion to heavy chain |
| D. | APUD (neuroendocrine) cells are of endodermal origin |
| E. | type II pneumocytes are membranous |
| Answer» F. | |
| 500. |
For the glial cells, which is TRUE? |
| A. | one schwann cell can myelinate up to 40 neurons |
| B. | oligodenotocytes are the scavenger cells of the CNS |
| C. | microglia are the scavenger cells of the PNS |
| D. | there are up to three glial cells per neuron in the nervous system |
| E. | protoplasmic astrocytesase found in grey matter |
| Answer» F. | |