McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Biology .
Chapters
| 301. |
Regarding a coronary blood flow: |
| A. | systolic blood flow in subendocardial arteries is greater than in the epicardial |
| B. | less than 50% of oxygen is removed during passage when in the resting state |
| C. | the coronary circulation is well supplied by parasympathetic vasodilatory fibres |
| D. | sympathetic vasoconstrictory fibres predominate in epicardial vessels |
| E. | none of the above |
| Answer» D. sympathetic vasoconstrictory fibres predominate in epicardial vessels | |
| 302. |
Active transport of Na+/K+ accounts for what percentage of energy utilised in cells and neurons? |
| A. | 20% cells, 50% neurons |
| B. | 24% cells, 50% neurons |
| C. | 24% cells, 70% neurons |
| D. | 30% cells, 70% neurons |
| E. | 30% cells, 90% neurons |
| Answer» C. 24% cells, 70% neurons | |
| 303. |
Human DNA – what proportion codes for proteins? |
| A. | 3% |
| B. | 13% |
| C. | 23% |
| D. | 33% |
| E. | 53% |
| Answer» A. 3% | |
| 304. |
Comparing nerve fibre types – which is FALSE? |
| A. | C fibres are most susceptible to local anaesthetic |
| B. | A fibres are least susceptible to local anaesthetic |
| C. | B fibres are found preganglionic – autonomic |
| D. | Aδ fibres transmit motor to muscle spindles |
| E. | some C fibres transmit postganglionic sympathetic impulses |
| Answer» D. Aδ fibres transmit motor to muscle spindles | |
| 305. |
Nicotinic receptors, which is FALSE? |
| A. | are found on sympathetic ganglia |
| B. | are found at the neuromuscular junction |
| C. | are activated by ACh |
| D. | cause activation of a G protein and ↑cAMP |
| E. | cause influx of Na+ via open Na+ channels |
| Answer» D. cause activation of a G protein and ↑cAMP | |
| 306. |
Serotonin is noted in all but: |
| A. | sexual behaviour |
| B. | obesity |
| C. | platelet aggregation |
| D. | mood |
| E. | vomiting |
| Answer» A. sexual behaviour | |
| 307. |
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» A. the ??? columns connect with the medial branches (crosses midline) | |
| 308. |
With respect to the EEG and brain wave activity – which is FALSE? |
| A. | the α rhythm (adults) has a frequency of 18-30/second |
| B. | infants have a faster β rhythm than adults |
| C. | the frequency of the α rhythm can be decreased with hypoglycaemia, hypothermia and increased ??? |
| D. | young adult – 25% sleep is REM sleep |
| E. | REM sleep is characterised by no muscle tone, but increased extraocular movement |
| Answer» B. infants have a faster β rhythm than adults | |
| 309. |
Which of the following decreases basal metabolic rate? |
| A. | recent ingestion of food |
| B. | stress |
| C. | increased thyroid hormones |
| D. | sleep |
| E. | lactation |
| Answer» D. sleep | |
| 310. |
Which of the following is an example of a low energy phosphate compound: |
| A. | creatine phosphate |
| B. | UTP |
| C. | acetyl CoA |
| D. | glucose-6 phosphate |
| E. | ATP |
| Answer» D. glucose-6 phosphate | |
| 311. |
Creatinuria occurs in measurable amounts in all but: |
| A. | women during and after pregnancy and occasionally in non-pregnant women |
| B. | normal men |
| C. | starvation |
| D. | thyrotoxicosis |
| E. | poorly controlled diabetes mellitus |
| Answer» B. normal men | |
| 312. |
Plasma lipids and lipid transport: |
| A. | apoprotein B48 occurs in VLDL |
| B. | apoprotein B166 and apoprotein C occurs in chylomicrons |
| C. | lecithin cholesterol acyltrasferase is responsible for transferring cholesterol esters from HDL to… |
| D. | chylomicron remnants travel from the intestine within lymphatic fluid in the thoracic duct |
| E. | one half of all LDL molecules is taken up by macrophages and other cells by means other than the LDL receptor |
| Answer» C. lecithin cholesterol acyltrasferase is responsible for transferring cholesterol esters from HDL to… | |
| 313. |
Adrenal insufficiency may cause all but which of the following? |
| A. | inability to excrete a water load |
| B. | personality changes |
| C. | sodium loss with circulatory insufficiency |
| D. | hypoglycaemia in the presence of fasting |
| E. | leukocytosis |
| Answer» E. leukocytosis | |
| 314. |
Hyperaldosteronism: |
| A. | causes low plasmic Na+ and high H+ |
| B. | retains acid H+ ions and can cause acidosis |
| C. | doesn’t cause oedema due to the escape phenomenon |
| D. | may cause hypocalcaemic nephropathy |
| E. | may be caused by high sodium intake |
| Answer» C. doesn’t cause oedema due to the escape phenomenon | |
| 315. |
Bone: |
| A. | osteoblasts are multinucleate |
| B. | osteoclasts attach to bone via integins |
| C. | compact bone makes up 60% of a long bone |
| D. | osteoblasts secrete large quantities of type IV collagen and other bone matrix proteins |
| E. | oestrogens inhibit osteoblasts and stimulate osteoclasts |
| Answer» B. osteoclasts attach to bone via integins | |
| 316. |
Daily water turnover in the gastrointestinal tract: |
| A. | the stomach contributes about 2500ml resorption |
| B. | jejunum resorbs 1300ml of the water |
| C. | the colon absorbs the bulk of the water load |
| D. | the ??? toxin causes achenyl cyclase therefore ↑cAMP and ↑ Clsecretion, ↓ ??? |
| E. | stool balance (average) is 500ml |
| Answer» D. the ??? toxin causes achenyl cyclase therefore ↑cAMP and ↑ Clsecretion, ↓ ??? | |
| 317. |
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» D. glomerular membrane permits passage of small (???) neutral substances | |
| 318. |
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» B. the macula densa is ??? tubular epithelium of the collecting duct | |
| 319. |
Regulation of renal blood flow – which is FALSE? |
| A. | angiotensin II constricts the afferent arteriole and efferent arteriole |
| B. | noradrenaline constricts intertubular arteries and afferent arterioles |
| C. | dopamine causes vasodilation in renal vessels and natriuresis |
| D. | ACh – renal vasodilation |
| E. | prostaglandins increase blood flow to the cortex and decrease it in the medulla |
| Answer» A. angiotensin II constricts the afferent arteriole and efferent arteriole | |
| 320. |
All but which of the following cause contraction of the mesengial cells? |
| A. | endothelins |
| B. | angiotensin II |
| C. | ADH |
| D. | noradrenaline |
| E. | cAMP |
| Answer» E. cAMP | |
| 321. |
All but which of the following are involved in the movement of Na+/Cl- across the apical membrane of the proximal tubules? |
| A. | Na+ / 2Cl- / K+ co-transporter (CT) |
| B. | Na+/ glucose CT |
| C. | Na+/P??? CT |
| D. | Cl- / base exchanges |
| E. | Na+ / H+ exchanges |
| Answer» A. Na+ / 2Cl- / K+ co-transporter (CT) | |
| 322. |
B nerve fibres: |
| A. | provide motor supply to intrafusal muscle fibres |
| B. | are usually the first fibres affected by local anaesthetics |
| C. | are 12-20umol in diameter |
| D. | are unmyelinated |
| E. | provide pre-ganglionic autonomic supply |
| Answer» E. provide pre-ganglionic autonomic supply | |
| 323. |
Ionic: |
| A. | movement across an impermeable membrane occurs due to an osmotic gradient |
| B. | equilibrium potential can be determined using the Nernst equation |
| C. | movement across the capillary wall is not affected by the Donnan effect |
| D. | valency determines osmotic effect in an ideal solution |
| E. | forms of weak acids cross cell membranes easily |
| Answer» B. equilibrium potential can be determined using the Nernst equation | |
| 324. |
Steroid hormones: |
| A. | open ion channels in cell membrane |
| B. | act via cytoplasmic or nuclear receptors |
| C. | increase intracellular cAMP |
| D. | increase tyrosine kinase activity of transmembrane receptors |
| E. | act via a serpentine receptor |
| Answer» B. act via cytoplasmic or nuclear receptors | |
| 325. |
Cardiac muscle fibres: |
| A. | develop tetany only at very high stimulation frequencies |
| B. | develop less tension when stretched due to decreased actin-myosin overlap |
| C. | can derive only 5% of basal caloric requirement from fat |
| D. | have a T-system located at the A-I junctions |
| E. | remain absolutely refractory until the membrane potential repolarises to - 50mV |
| Answer» E. remain absolutely refractory until the membrane potential repolarises to - 50mV | |
| 326. |
Glomeruli: |
| A. | minimally filters protein, so plasma protein concentration is not altered |
| B. | are supplied by an extensive anastomotic arterial network |
| C. | lie distal to the juxtaglomerular apparatus |
| D. | each receive approximately 20-25% of resting cardiac output |
| E. | do not filter appreciable albumin since membrane pores are too small |
| Answer» C. lie distal to the juxtaglomerular apparatus | |
| 327. |
The distal tubule: |
| A. | absorbs most of the filtered sodium ions in the presence of aldosterone |
| B. | absorbs glucose in the normal state |
| C. | absorbs most of the filtered water in the presence of ADH |
| D. | secretes hydrogen via secondary active transport |
| E. | is almost entirely impermeable to urea |
| Answer» E. is almost entirely impermeable to urea | |
| 328. |
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» B. 1,25-dihydroxycholecalciferol receptors can be found in skin | |
| 329. |
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» D. creatinuria occurs normally in children | |
| 330. |
Which pattern of laboratory findings in the tale below is most consistent with a diagnosis of diabetes insipidis? 24 Hr Urine Volume Ketones Glucose Protein |
| A. | 4.0 + 0 0 |
| B. | 6.2 2+ 4+ 0 |
| C. | 1.6 0 0 4+ |
| D. | 6.4 0 0 0 |
| E. | 5.0 0 0 3+ |
| Answer» D. 6.4 0 0 0 | |
| 331. |
Angiotensin H causes: |
| A. | greater constriction of efferent than afferent arterioles |
| B. | greater constriction of afferent than efferent arterioles |
| C. | constriction of afferent arterioles only |
| D. | constriction of efferent arterioles only |
| E. | has no effect on arteriolar constriction |
| Answer» A. greater constriction of efferent than afferent arterioles | |
| 332. |
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» C. the afferent arteriole is constricted by thromboxane A2 | |
| 333. |
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» B. solutes diffuse out of vessels conducting blood towards the cortex | |
| 334. |
What is the clearance of a substance when its concentration in plasma is 1mg/ml, its concentration in urine is 10mg/ml and the urine flow is 2ml/min |
| A. | 2ml/min |
| B. | 10ml/min |
| C. | 20ml/min |
| D. | 200ml/min |
| E. | clearance cannot be determined from the information given |
| Answer» C. 20ml/min | |
| 335. |
Regarding the proximal tubule, the following statements are true EXCEPT: |
| A. | Na is co-transported out of the tubule with glucose |
| B. | Na is actively transported into the intercellular spaces by Na-K ATPase |
| C. | the cells are characterised by a brush border and tight junctions |
| D. | vasopressin increases the permeability to water by causing the rapid insertion of water channels into the luminal membrane |
| E. | water moves passively out of the tubule along osmotic gradients |
| Answer» D. vasopressin increases the permeability to water by causing the rapid insertion of water channels into the luminal membrane | |
| 336. |
With regard to the effect of hormones on renal tubules, which is CORRECT? |
| A. | aldosterone increases K reabsorption from the distal tubule |
| B. | angiotensin II increases H+ secretion from the proximal tubules |
| C. | ADH increases water reabsorption in the proximal tubule |
| D. | atrial naturetic peptide decreases Na+ reabsorption from the proximal tubules |
| E. | parathyroid hormone increases phosphate reabsorption |
| Answer» B. angiotensin II increases H+ secretion from the proximal tubules | |
| 337. |
The thin ascending loop of Henle is: |
| A. | relatively permeable to water |
| B. | relatively impermeable to Na+ |
| C. | permeable to both water and Na+ |
| D. | relatively impermeable to water |
| E. | relatively impermeable to both water and Na+ |
| Answer» D. relatively impermeable to water | |
| 338. |
Action potential initiation in the sinoatrial and atrioventricular nodes results from: |
| A. | Na+ influx |
| B. | K+ influx |
| C. | Ca++ influx |
| D. | Na+ and Ca++ influx |
| E. | increased K+ conductance |
| Answer» C. Ca++ influx | |
| 339. |
Regarding isometric ventricular reaction: |
| A. | it occurs late in diastole |
| B. | ventricular filling occurs |
| C. | intraventricular pressure remains constant during this phase |
| D. | it ends when the AV valve close |
| E. | it ends when the AV valve open |
| Answer» E. it ends when the AV valve open | |
| 340. |
Local vasoconstriction results from: |
| A. | increased potassium concentration |
| B. | increased magnesium concentration |
| C. | increased sodium concentration |
| D. | decrease in pH |
| E. | increased calcium concentration |
| Answer» E. increased calcium concentration | |
| 341. |
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» D. right atrial pressure is decreased | |
| 342. |
With regard to ascending to high altitudes: |
| A. | there is a linear decrease in inspired oxygen pressures with increasing altitude |
| B. | the partial pressure of water vapour in moist inspired air decreases with PiO2 |
| C. | at 19,200m, barometric pressure = 47mmHg, PiO2 then is approx 9mmHg |
| D. | at peak at Mt Everest, barometric pressure = 380mmHg, PiO2 is approx 70mmHg |
| E. | in permanent residents of the Andes, arterial and venous PO2 is half normal levels |
| Answer» D. at peak at Mt Everest, barometric pressure = 380mmHg, PiO2 is approx 70mmHg | |
| 343. |
A 28-year-old lady has taken an overdose of sedatives causing her to hypoventilate. Given that her arterial PCO2 is now doubled to 80mmHg, which of the following is most likely to be correct, given that she is breathing room air at normal barometric pressures? |
| A. | arterial PO2 will be approximately 70mmHg |
| B. | arterial PO2 will be approximately 35mmHg |
| C. | arterial Hb O2 saturation will be approximately 50% |
| D. | arterial Hb O2 saturation will be approximately 80% |
| E. | arterial Hb O2 saturation will be approximately 27% |
| Answer» D. arterial Hb O2 saturation will be approximately 80% | |
| 344. |
Which of the following has the greatest effect on the ability of the blood to transport O2? |
| A. | the capacity of the blood to dissolve O2 |
| B. | the amount of Hb in the blood |
| C. | the pH of the plasma |
| D. | the CO2 content of red blood cells |
| E. | the temperature of the blood |
| Answer» B. the amount of Hb in the blood | |
| 345. |
The Haldane effect describes: |
| A. | the shift to the right of the O2 dissociation curve caused by increased PCO2 |
| B. | the enhanced loading of CO2 iii the presence of deoxygenated Hb |
| C. | the shift of chloride ions into red blood cells to balance HCO3 shift from those cells |
| D. | the action of carbonic anhydrase on carbonic acid |
| E. | none of the above |
| Answer» B. the enhanced loading of CO2 iii the presence of deoxygenated Hb | |
| 346. |
With regard to CO2 carriage in the blood: |
| A. | dissolved CO2 has an insignificant role in the carriage of CO2 in the blood |
| B. | HCO3 production is fast in plasma |
| C. | ionic dissociation of carbonic acid in the red cell is fast without an enzyme |
| D. | the CO2 concentration in blood is independent of the saturation of haemoglobin with oxygen |
| E. | the majority of CO2 is carried in the blood in the forms of dissolved CO2 and carbamino-compounds |
| Answer» C. ionic dissociation of carbonic acid in the red cell is fast without an enzyme | |
| 347. |
Substances cleared from the circulation by the lungs include all the following EXCEPT: |
| A. | angiotensin H |
| B. | serotonin |
| C. | leukotrienes |
| D. | bradykinin |
| E. | prostaglandin |
| Answer» A. angiotensin H | |
| 348. |
With regard to the normal Hb-ox-y-en dissociation curve, which is the most likely to be CORRECT? |
| A. | when arterial PO2 = 60mmHg, Hb saturation is ∼ 80% |
| B. | when arterial PO2 = 40mmHg, Hb saturation is ∼ 75% |
| C. | when arterial PO2 = 30mmHg, Hb saturation is ∼ 40% |
| D. | acidosis shifts the curve to the left |
| E. | decreased PCO2 shifts the curve to the right |
| Answer» B. when arterial PO2 = 40mmHg, Hb saturation is ∼ 75% | |
| 349. |
Increased lung compliance is associated with: |
| A. | increasing age |
| B. | increasing pulmonary venous pressure |
| C. | high expanding pressures |
| D. | interstitial fibrosis |
| E. | low lung volumes associated with hypoventilation |
| Answer» A. increasing age | |
| 350. |
The following physiological events that occur in the body are listed in random sequence:
|
| A. | a, b, c, d, e |
| B. | d, a, c, b, e, |
| C. | c, d, e, b, a, |
| D. | e, b, c, a, d, |
| E. | e, c, b, d, a |
| Answer» D. e, b, c, a, d, | |
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