Quiznetik

Physiology | Set 4

1. 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

Correct : D. sympathetic vasoconstrictory fibres predominate in epicardial vessels

2. 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

Correct : C. 24% cells, 70% neurons

4. 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

Correct : D. Aδ fibres transmit motor to muscle spindles

5. 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

Correct : D. cause activation of a G protein and ↑cAMP

7. 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

Correct : A. the ??? columns connect with the medial branches (crosses midline)

8. 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

Correct : B. infants have a faster β rhythm than adults

9. Which of the following decreases basal metabolic rate?

10. Which of the following is an example of a low energy phosphate compound:

11. 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

Correct : B. normal men

12. 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

Correct : C. lecithin cholesterol acyltrasferase is responsible for transferring cholesterol esters from HDL to…

13. 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

Correct : E. leukocytosis

14. 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

Correct : C. doesn’t cause oedema due to the escape phenomenon

15. 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

Correct : B. osteoclasts attach to bone via integins

16. 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

Correct : D. the ??? toxin causes achenyl cyclase therefore ↑cAMP and ↑ Clsecretion, ↓ ???

17. 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

Correct : D. glomerular membrane permits passage of small (???) neutral substances

18. 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

Correct : B. the macula densa is ??? tubular epithelium of the collecting duct

19. 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

Correct : A. angiotensin II constricts the afferent arteriole and efferent arteriole

20. All but which of the following cause contraction of the mesengial cells?

21. 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

Correct : A. Na+ / 2Cl- / K+ co-transporter (CT)

22. 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

Correct : E. provide pre-ganglionic autonomic supply

23. 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

Correct : B. equilibrium potential can be determined using the Nernst equation

24. 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

Correct : B. act via cytoplasmic or nuclear receptors

25. 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

Correct : E. remain absolutely refractory until the membrane potential repolarises to - 50mV

26. 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

Correct : C. lie distal to the juxtaglomerular apparatus

27. 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

Correct : E. is almost entirely impermeable to urea

28. 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

Correct : B. 1,25-dihydroxycholecalciferol receptors can be found in skin

29. 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

Correct : D. creatinuria occurs normally in children

30. 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

31. 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

Correct : A. greater constriction of efferent than afferent arterioles

32. 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

Correct : C. the afferent arteriole is constricted by thromboxane A2

33. 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

Correct : B. solutes diffuse out of vessels conducting blood towards the cortex

34. 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

35. 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

Correct : D. vasopressin increases the permeability to water by causing the rapid insertion of water channels into the luminal membrane

36. 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

Correct : B. angiotensin II increases H+ secretion from the proximal tubules

37. 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+

Correct : D. relatively impermeable to water

38. Action potential initiation in the sinoatrial and atrioventricular nodes results from:

39. 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

Correct : E. it ends when the AV valve open

40. Local vasoconstriction results from:

A. increased potassium concentration

B. increased magnesium concentration

C. increased sodium concentration

D. decrease in pH

E. increased calcium concentration

Correct : E. increased calcium concentration

41. 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

Correct : D. right atrial pressure is decreased

42. 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

Correct : D. at peak at Mt Everest, barometric pressure = 380mmHg, PiO2 is approx 70mmHg

43. 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%

Correct : D. arterial Hb O2 saturation will be approximately 80%

44. 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

Correct : B. the amount of Hb in the blood

45. 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

Correct : B. the enhanced loading of CO2 iii the presence of deoxygenated Hb

46. 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

Correct : C. ionic dissociation of carbonic acid in the red cell is fast without an enzyme

47. Substances cleared from the circulation by the lungs include all the following EXCEPT:

48. 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

Correct : B. when arterial PO2 = 40mmHg, Hb saturation is ∼ 75%

49. 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

Correct : A. increasing age

50. The following physiological events that occur in the body are listed in random sequence: a. decreased CSF pH b. increased PaCO2 c. increased CSF PCO2 d. stimulation of medullary chemoreceptors e. increased PACO2 What is the usual sequence?

51. In relation to acid base balance in the body:

A. respiratory compensation in metabolic alkalosis is limited by carotid and aortic chemoreceptor response

B. HCO3 concentration will decrease in compensated respiratory acidosis

C. the rate of renal H+ secretion is not affected by PCO2 in respiratory acidosis

D. chloride excretion is decreased in respiratory acidosis

E. hepatic glutamine synthesis is decreased in chronic metabolic acidosis

Correct : A. respiratory compensation in metabolic alkalosis is limited by carotid and aortic chemoreceptor response

52. The action potential of a neuron:

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 gradient of Na+ across the cell membrane

E. is not associated with any net movement of Na+ or K+ across the cell membrane

Correct : B. is terminated by efflux of K+

53. The functions of tropomyosin in skeletal muscle include:

A. releasing Ca++ after an action potential

B. sliding on actin to produce shortening

C. binding to myosin during contraction

D. acting as a “relaxing protein” at rest by covering up the sites where myosin binds to actin

E. generating ATP which passes to the contractile mechanism

Correct : D. acting as a “relaxing protein” at rest by covering up the sites where myosin binds to actin

54. Regarding the autonomic nervous system:

A. does not have a reflex like somatic nervous system

B. has dopamine as the main transmitter

C. has cholinergic division which increases activity of the intestinal musculature and increases gastric secretion

D. neurotransmitter noradrenaline is metabolised by pseudocholinesterase

E. is not involved with visceral sensation

Correct : C. has cholinergic division which increases activity of the intestinal musculature and increases gastric secretion

55. Lymph flow is:

A. an average 500ml/hr into the circulation

B. proportional to interstitial fluid pressure

C. increased with decreased interstitial fluid protein

D. decreased with contraction of muscles

E. decreased with elevated capillary pressure

Correct : B. proportional to interstitial fluid pressure

56. Regarding the intracellular fluid, which is NOT CORRECT?

A. it accounts for 40% of body weight

B. its volume can be estimated using radio-active inulin

C. it contains more protein (in mg/L water) than extracellular fluid

D. the composition of intracellular fluid varies with the nature and function of the cell

E. all of the above are true

Correct : B. its volume can be estimated using radio-active inulin

57. Regarding extracellular volume maintenance:

A. control of sodium balance is the major mechanism maintaining ECF volume

B. a rise in ECF volume stimulates vasopressin secretion

C. osmotic stimuli over-ride volume stimuli in the regulation of vasopressin secretion

D. vasopressin causes Na+ retention by the kidney

E. angiotensin II inhibits aldosterone secretion

Correct : A. control of sodium balance is the major mechanism maintaining ECF volume

58. Regarding renal compensation in respiratory acidosis and alkalosis:

A. the rate of HCO3 reabsorption is inversely proportional to the arterial PCO2

B. in respiratory acidosis, HCO3 reabsorption is reduced

C. changes in plasma chloride concentration are proportional to CHO3 concentration

D. in respiratory alkalosis, renal H+ secretion is increased

E. HCO3 reabsorption depends upon the rate of H+ secretion by the renal tubular cells

Correct : E. HCO3 reabsorption depends upon the rate of H+ secretion by the renal tubular cells

59. Regarding calcium metabolism:

A. approximately 60% of filtered calcium is reabsorbed by the kidney

B. absorption of calcium in the gastrointestinal tract is mainly by passive diffusion

C. the extent of Ca++ binding by plasma proteins is inversely proportionate to the plasma protein level

D. levels of 1,25-dihydroxycholecalciferol fall in the presence of increased plasma Ca++

E. the majority of calcium present in bone is readily exchangeable

Correct : D. levels of 1,25-dihydroxycholecalciferol fall in the presence of increased plasma Ca++

60. Toxins that increase the cyclic AMP content of the intestinal mucosa cause diarrhoea because they:

A. increase Cl- secretion into the intestinal lumen

B. increase Na+ absorption in the small intestine

C. increase K+ secretion into the colon

D. increase Na+/K+ co-transport K+ secretion into the colon

E. none of the above

Correct : A. increase Cl- secretion into the intestinal lumen

61. Which of the following is NOT synthesised in post-ganglionic sympathetic neurons:

62. 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

Correct : E. none of the above are true

63. In the Erlanger and Gasser classification of nerve fibres:

A. C fibres have the fastest conduction velocity

B. Aγ fibres are responsible for touch and pressure

C. C fibres are most susceptible to local anaesthetics

D. Aα fibres have the fastest conduction velocity and the longest absolute refractory period

E. A fibres are most susceptible to hypoxia

Correct : C. C fibres are most susceptible to local anaesthetics

64. Regarding neurotrophins:

A. NGF and BDNF share the same receptor

B. the structure of the β subunit of NGF resembles that of insulin

C. CNTF is necessary for the growth and maintenance of sympathetic neurons

D. disruption of GDNF by gene knockout causes a marked loss of cutaneous mechanoreceptors

E. none of the above are true

Correct : B. the structure of the β subunit of NGF resembles that of insulin

65. Regarding cardiac muscle:

A. cardiac muscle has high ATPase activity

B. only the α MHC isoform is found in the atria

C. resting membrane potential is about -70mV

D. force of contraction is mediated by catecholamines acting via β1 -adrenergic receptors

E. mutations of the human ether-a-go-go gene causes minks to shake their legs uncontrollably

Correct : D. force of contraction is mediated by catecholamines acting via β1 -adrenergic receptors

66. Which of the following does not decrease smooth muscle membrane potential?

67. In regard to plasma volume:

A. it contributes to 10% of body weight

B. can easily be measured by radioisotope chromium

C. if the plasma volume is known, the blood volume can be calculated by multiplying100-HCT/100

D. measured by injecting Evans blue

E. the average plasma volume is 500ml

Correct : D. measured by injecting Evans blue

68. Which of the following is FALSE?

A. the ECF represents 20% of body weight

B. the blood volume represents 8% of the body weight

C. the 2/3 of the body water is in ICF

D. 18% of the body weight is protein

E. the transcellular fluids contribute to 5% of the body weight

Correct : E. the transcellular fluids contribute to 5% of the body weight

69. Which of the following is FALSE?

A. diffusion depends on concentration gradient of the solutes

B. osmotic pressure of a solution is inversely related to the volume of the solution

C. when 5% dextrose is infused, it becomes hypotonic to the plasma in the body

D. osmolality is defined as osmotically active particles in 1L of solution

E. osmolality is defined as a number of osmotically active particles in 1kg of solvent

Correct : D. osmolality is defined as osmotically active particles in 1L of solution

70. Regarding cell membrane, which of the following is FALSE?

A. the diameter of the cell membrane is about 7.5nm

B. 50% of the cell membrane is made up of proteins

C. the main lipids of the cell membrane are phospholipids

D. the hydrophilic ends of the lipid molecules are faced towards the interior of the cell membrane

E. the proteins in the cell membrane function as carriers, ion channels, enzymes and receptors

Correct : D. the hydrophilic ends of the lipid molecules are faced towards the interior of the cell membrane

71. Regarding mitochondria, which of the following is TRUE?

A. 99% of mitochondrial proteins are products of mitochondrial DNA

B. the outer membrane of the mitochondria is folded to form cristae

C. the space between the outer and inner mitochondrial space is called matrix space

D. it is the sperm which contributes to the formation of mitochondria in the zygote

E. the synthesis of ATP in the mitochondria is triggered by diffusion of H+ from matrix to intracristal space

Correct : E. the synthesis of ATP in the mitochondria is triggered by diffusion of H+ from matrix to intracristal space

72. Which is FALSE?

A. fast fibres have small number of mitochondria

B. fast fibres are called white muscles

C. the glycolic processes are more important in energy supply in fast fibres

D. slow fibres are also called red fibres

E. fast fibres have more extensive blood supply than slow fibres

Correct : E. fast fibres have more extensive blood supply than slow fibres

73. Smooth muscles differ from skeletal muscle by:

A. not having actin/myosin

B. not having striated appearance

C. not using ATP for contraction

D. not using Ca2+ for contraction

E. not having sarcoplasmic reticulum

Correct : B. not having striated appearance

75. The highest number of voltage gated Na+ channels are found in:

76. Which of the following nerve fibres is most susceptible to hypoxia?

77. Which of the following is most susceptible to pressure?

78. Regarding nerve action potential, which is TRUE?

A. normal resting membrane potential is -40mV

B. initial rapid depolarisation is due to rapid influx of Ca2+ via fast channels

C. during depolarisation, Na+ permeality is greater than K+ permeality

D. hyperpolarisation is due to continuous opening of Na+ channels

E. plateau is formed by slow Ca2+ channels

Correct : C. during depolarisation, Na+ permeality is greater than K+ permeality

79. Which is FALSE regarding secondary active transport?

A. it always transports substances in one direction

B. energy required is obtained by Na+ /K+ ATPase pump

C. a good example is Na+ / glucose co-transport

D. Na+ / Ca2+ antiport is an example of secondary active transport

E. secondary active transport occurs in renal tubules

Correct : A. it always transports substances in one direction

80. Which is TRUE?

A. steroids act via cAMP

B. insulin acts via IP3

C. EGF+ erythropoietin act via cAMP

D. thyroid hormones act via G proteins

E. retinoic acid act via intracellular receptor → transcription of genes

Correct : E. retinoic acid act via intracellular receptor → transcription of genes

81. Na+ / K+ ATPase pump – which is FALSE?

A. it is electrogenic in nature

B. it is important in maintaining cell volume

C. plays a major role in secondary active transport

D. it is the main factor which determine the resting membrane potential

E. it is an example of primary active transport

Correct : D. it is the main factor which determine the resting membrane potential

82. Regarding serotonin:

A. the highest concentration is in the brain

B. formed by hydroxylation and decarboxylation of tyrosine

C. catabolised by COMT

D. some receptors are ion channels

E. mediates smooth muscle relaxation

Correct : D. some receptors are ion channels

83. GABA:

A. decreases Cl- conductance

B. is broken down by glutamate decarboxylase (GA????)

C. there are five receptor subtypes

D. benzodiazepines bind to the β subunit of the GABA receptor

E. is involved in 20% of CNS synapses

Correct : E. is involved in 20% of CNS synapses

84. Which is NOT present in high concentrations, at the active zone of synapses?

85. Which is not a ligand-gated ion channel?

86. Which drug is NOT involved in facilitating Cl- conductance?

87. Regarding skeletal muscle:

A. isotonic contraction does no work

B. calcium is released from troponin during contraction

C. the resting membrane potential is -70mV

D. treppe occurs in skeletal muscle only

E. white muscle has short twitch durations

Correct : E. white muscle has short twitch durations

88. Regarding cardiac muscle:

A. gap junctions provide high resistance bridges

B. T system of tubules located at A-I junctions

C. calcium binds to calmodulin

D. tetany is not possible due to the latch bridge mechanism

E. ↑cAMP leads to ↑ force of contraction

Correct : E. ↑cAMP leads to ↑ force of contraction

89. Regarding smooth muscle:

A. tropomyosin is absent

B. the resting membrane potential is -90mV

C. there is a highly developed sarcoplasmic reticulum

D. there are no spike potentials

E. dense bodies are attached to the cell membrane

Correct : E. dense bodies are attached to the cell membrane

90. Regarding synapses:

A. large vesicles contain ACh

B. Na+ influx triggers fusion / exocytosis of vesicles

C. I PSP can be produced by closing K channels

D. the synaptic cleft is 100-150nm

E. neurotransmitters migrate down the axon by fast axoplasmic transport

Correct : E. neurotransmitters migrate down the axon by fast axoplasmic transport

91. Regarding acetylcholine:

A. it is oxidised to choline and acetate by acetylcholinesterase

B. nicotinic receptors are blocked by atropine

C. it is the main excitatory transmitter in the spinal cord

D. it is secreted by the adrenal medulla

E. tetanus blocks its release at the NMJ

Correct : E. tetanus blocks its release at the NMJ

92. 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-

Correct : C. chemical mediators located in ???? of presynaptic fibres contain one-way conduction of impulses

93. Transmitters – all are true EXCEPT:

A. angiotensin II is a neurotransmitter of the polypeptidillars

B. glutamate is an inhibitory amino acid

C. glucagons is found in hypothalamus and retina

D. vasopressin is found in posterior pituitary, medulla, spinal cord

E. serotonin is an amine

Correct : B. glutamate is an inhibitory amino acid

94. Neurotransmitters:

A. atropine blocks effect of acetylcholine at ???? receptor

B. reaction between active acetate and choline is catalysed by acetylcholinesterase

C. nicotinic cholinergic receptors are serpentine receptors

D. the rate limiting step in synthesis of NOVA is ?????(concussion) of tyrosine to dopa

E. MAOA is found in nerve endings and platelets

Correct : D. the rate limiting step in synthesis of NOVA is ?????(concussion) of tyrosine to dopa

95. Regarding muscle spindles:

A. are composed of extrafusal fibres

B. receive δ efferents

C. all subtypes send afferents via “flower spray” ended 1a nerves

D. nuclear chain fibres show dynamic response

E. afferent discharge decreased with muscle stretch

Correct : B. receive δ efferents

96. Regarding the dorsal column:

A. carries ipsilateral pain and temperature

B. ascends to the nuclei gracillis and ?????

C. receives efferents from contralateral stimuli

D. sacral efferents lie laterally

E. runs anteriorly in the cord

Correct : B. ascends to the nuclei gracillis and ?????

97. Temperature sensation:

A. respond to compartitive temp gradient ??? skin

B. cold receptors predominate

C. warm receptors respond 30° - 100°

D. afferents carried via the dorsal column

E. warm and cold afferents carried via Ad fibre

Correct : B. cold receptors predominate

98. Regarding visual receptors:

A. rods predominate in the jovea

B. rhodopsin is the primary pigment of rods

C. lie anterior (superficial) to their neural pathway

D. colour blindness is an autosomal recessive gene

E. supplied by retinal vessels

Correct : B. rhodopsin is the primary pigment of rods

99. Regarding sound and hearing:

A. high pitched sounds are detected at the apex of the cochlear

B. Harr cells are bathed in endolymph

C. defected by hair cells found within the tectorium membrane

D. 95% of afferent neurones → outer ??? cells

E. supplied by retinal vessels

Correct : E. supplied by retinal vessels

100. Regarding noradrenergic stimulation:

A. miosis occurs

B. increases blood flow to the skin

C. increases thresholds in the reticular formation

D. causes erection in males

E. elevates free fatty acid levels

Correct : D. causes erection in males

Quiznetik

Physiology | Set 4

1. Regarding a coronary blood flow:

2. Active transport of Na+/K+ accounts for what percentage of energy utilised in cells and neurons?

3. Human DNA – what proportion codes for proteins?

4. Comparing nerve fibre types – which is FALSE?

5. Nicotinic receptors, which is FALSE?

6. Serotonin is noted in all but:

7. With respect to the ascending pathways of sensation within the spinal cord:

8. With respect to the EEG and brain wave activity – which is FALSE?

9. Which of the following decreases basal metabolic rate?

10. Which of the following is an example of a low energy phosphate compound:

11. Creatinuria occurs in measurable amounts in all but:

12. Plasma lipids and lipid transport:

13. Adrenal insufficiency may cause all but which of the following?

14. Hyperaldosteronism:

15. Bone:

16. Daily water turnover in the gastrointestinal tract:

17. Functional anatomy of the kidney – which is TRUE?

18. Functional anatomy of the kidney – which is FALSE?

19. Regulation of renal blood flow – which is FALSE?

20. All but which of the following cause contraction of the mesengial cells?

21. All but which of the following are involved in the movement of Na+/Cl- across the apical membrane of the proximal tubules?

22. B nerve fibres:

23. Ionic:

24. Steroid hormones:

25. Cardiac muscle fibres:

26. Glomeruli:

27. The distal tubule:

28. Regarding vitamin D metabolism:

29. Regarding protein metabolism:

30. 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

31. Angiotensin H causes:

32. With regard to tuboglomerular feedback:

33. With respect to the counter current system:

34. 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

35. Regarding the proximal tubule, the following statements are true EXCEPT:

36. With regard to the effect of hormones on renal tubules, which is CORRECT?

37. The thin ascending loop of Henle is:

38. Action potential initiation in the sinoatrial and atrioventricular nodes results from:

39. Regarding isometric ventricular reaction:

40. Local vasoconstriction results from:

41. In compensated low output cardiac failure:

42. With regard to ascending to high altitudes:

43. 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?

44. Which of the following has the greatest effect on the ability of the blood to transport O2?

45. The Haldane effect describes:

46. With regard to CO2 carriage in the blood:

47. Substances cleared from the circulation by the lungs include all the following EXCEPT:

48. With regard to the normal Hb-ox-y-en dissociation curve, which is the most likely to be CORRECT?

49. Increased lung compliance is associated with:

50. The following physiological events that occur in the body are listed in random sequence: a. decreased CSF pH b. increased PaCO2 c. increased CSF PCO2 d. stimulation of medullary chemoreceptors e. increased PACO2 What is the usual sequence?

51. In relation to acid base balance in the body:

52. The action potential of a neuron:

53. The functions of tropomyosin in skeletal muscle include:

54. Regarding the autonomic nervous system:

55. Lymph flow is:

56. Regarding the intracellular fluid, which is NOT CORRECT?

57. Regarding extracellular volume maintenance:

58. Regarding renal compensation in respiratory acidosis and alkalosis:

59. Regarding calcium metabolism:

60. Toxins that increase the cyclic AMP content of the intestinal mucosa cause diarrhoea because they:

61. Which of the following is NOT synthesised in post-ganglionic sympathetic neurons:

62. With reference to the action potential:

63. In the Erlanger and Gasser classification of nerve fibres:

64. Regarding neurotrophins:

65. Regarding cardiac muscle:

66. Which of the following does not decrease smooth muscle membrane potential?

67. In regard to plasma volume:

68. Which of the following is FALSE?

69. Which of the following is FALSE?

70. Regarding cell membrane, which of the following is FALSE?

71. Regarding mitochondria, which of the following is TRUE?

72. Which is FALSE?

73. Smooth muscles differ from skeletal muscle by:

74. Which of the following is absent in smooth muscle?

75. The highest number of voltage gated Na+ channels are found in:

76. Which of the following nerve fibres is most susceptible to hypoxia?

77. Which of the following is most susceptible to pressure?

78. Regarding nerve action potential, which is TRUE?