Quiznetik
Physiology | Set 8
1. The transport of which of the following gases is DIFFUSION LIMITED?
A. O2
B. N2O
C. CO2
D. CO
E. halothane
Correct : D. CO
2. With regard to anatomic dead space, all of the following are true EXCEPT:
A. it is calculated by Bohr’s method
B. the normal value is about 150ml
C. it increases with large inspirations
D. depends on the size of the subject
E. it is equivalent to the conducting zone
Correct : A. it is calculated by Bohr’s method
3. Which of the following is INCORRECT?
A. haemoglobin S causes the O2 curve to shift to the left
B. the O2 dissociation curve is shifted to the right by an increased PCO2, H+ concentration and temperature
C. carboxy haemoglobin has 240 times the affinity of O2 for Hb
D. COHB shift the O2 dissociation over to the left
E. it is equivalent to the conducting zone
Correct : A. haemoglobin S causes the O2 curve to shift to the left
4. 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
Correct : C. arterial oxygen less than 70mmHg markedly stimulates respiration via the carotid bodies
5. 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
Correct : B. V = (A.D.(P1 – P2))/T
6. Regarding surfactant, which statement is INCORRECT?
A. it predominantly consists of phospholipid
B. it is increased by long-term 100% oxygen therapy
C. hydrophobic “tails” face into alveolar lumen
D. it is decreased by cigarette smoking
E. pulmonary oedema is a consequence of its absence
Correct : B. it is increased by long-term 100% oxygen therapy
7. 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
Correct : E. increased carboxy haemoglobin
8. Regarding exercise, which statement is INCORRECT?
A. the energy cost of breathing is up to 10% of total energy expenditure
B. total pulmonary ventilation increases by up to 20 fold
C. total oxygen consumption increases by up to 20 fold
D. total carbon dioxide production increases by up to 40 fold
E. P5O increases
Correct : A. the energy cost of breathing is up to 10% of total energy expenditure
9. Total lung capacity is equal to:
A. vital capacity + tidal volume
B. vital capacity + functional residual capacity
C. tidal volume + residual volume
D. functional residual capacity + tidal volume
E. vital capacity + residual volume
Correct : E. vital capacity + residual volume
10. Regarding compliance, which statement is INCORRECT?
A. functional residual capacity is the equilibrium volume when elastic recoil of lung is balanced by normal tendency for chest wall to spring out
B. hysteresis is due to frictional resistance to air movement
C. compliance is greater in expiration than in inspiration
D. compliance is increased in emphysema
E. compliance is a dynamic measure of lung and chest wall recoil
Correct : E. compliance is a dynamic measure of lung and chest wall recoil
11. Which of the following is NOT involved in the control of ventilation?
A. peripheral chemoreceptors
B. lung stretch receptors
C. basal ganglia
D. pons
E. respiratory muscles
Correct : C. basal ganglia
12. 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
Correct : D. advancing age
13. 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
Correct : C. ventilation decreases proportionately more than perfusion from base to apex
14. 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
Correct : B. E.coli endotoxin causes venodilatation
15. 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
Correct : A. physiological dead space is normally larger than anatomical dead space
16. Which of the following DOES NOT constrict pulmonary arterioles?
A. adrenaline
B. thromboxane B2
C. noradrenaline
D. prostaglandin F2 α
E. isoproteronol
Correct : E. isoproteronol
17. 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
Correct : D. inspiratory capacity = 3300ml
18. Regarding carbon dioxide transport in blood, which statement is INCORRECT?
A. oxygen is about 20 times less soluble in blood
B. deoxygenation of blood increase its ability to carry carbon dioxide
C. arterial blood transports about 20% in dissolved form
D. venous blood has higher haematocrit than arterial blood
E. carbamino compounds are formed by reaction with both plasma proteins and Hb
Correct : C. arterial blood transports about 20% in dissolved form
19. Which of the following does NOT increases synthesis of 2, 3-DPG?
A. growth hormone
B. phosphate deficiency
C. thyroid hormone
D. exercise for one hour
E. androgens
Correct : B. phosphate deficiency
20. Which of the following DOES NOT shift the oxygen-haemoglobin dissociation curve to the right?
A. decreased phosphate
B. increased altitude
C. cortisol
D. decreased pH
E. aldosterone
Correct : A. decreased phosphate
21. 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
Correct : E. type II pneumocytes are membranous
22. Which of the following substances is NOT removed from the blood by the lung?
A. prostaglandins
B. noradrenaline
C. acetylcholine
D. adrenaline
E. bradykinin
Correct : D. adrenaline
23. 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
Correct : C. nitrous oxide is a diffusion limited gas
24. Which of the following substances is NOT synthesised by the lung?
A. prostaglandins
B. serotonin
C. dipalmityl phosphatidylcholine
D. histamine
E. kallikrein
Correct : B. serotonin
25. Exercise has all of the following effects on blood gases EXCEPT:
A. increased PACO2
B. increased PAO2
C. unchanged PaCO2
D. unchanged PaO2
E. increased PvCO2
Correct : A. increased PACO2
26. Regarding equilibrium potential (mammalian spinal motor neurons)
A. The resting membrane potential is – 70 mV – identical to that of Ecl
B. Equilibrium potential of potassium is +90 mV
C. Increases in external sodium concentrations decrease the resting membrane potential
D. Equilibrium potential of sodium is –60 mV
E. Na+K+ ATPase pumps 2 sodium out of cell for every 3 potassium it pumps in
Correct : A. The resting membrane potential is – 70 mV – identical to that of Ecl
27. Regarding body composition
A. 18% body weight is protein / related substances
B. 15% body weight is interstitial fluid
C. 60% body weight is water
D. 5% body weight is plasma
E. All of the above are true
Correct : E. All of the above are true
28. Regarding buffers in the body
A. Initial correction of pH disturbance is achieved by the kidneys
B. The phosphate buffer system is the predominant buffer in the blood
C. Bones contribute to buffering by taking up bicarbonate
D. Hb is an important buffer in the blood
E. All of the above are true
Correct : D. Hb is an important buffer in the blood
29. The size of the action potential is decreased by
A. Decreased extracellular calcium
B. Increased external sodium
C. Decreased internal sodium
D. Decreased internal potassium
E. Increased internal potassium
Correct : C. Decreased internal sodium
30. Regarding body fluid compartments
A. About 2/3 TBW is extracellular
B. ECF / intracellular fluid volume ratio is larger in infants than in adults
C. Plasma volume in a 70 kg male is approximately 5 litres
D. A 30 year old male has 40% water as a percentage of body weight
E. Transcellular fluid has a greater volume than intracellular fluids
Correct : B. ECF / intracellular fluid volume ratio is larger in infants than in adults
31. Fick’s Law of Diffusion is dependent on all EXCEPT
A. The posture of the subject
B. The solubility of the gas
C. Thickness of membrane barrier
D. Molecular weight of the gas
E. Area of the membrane
Correct : A. The posture of the subject
32. 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
Correct : B. Insulin reuptake is by receptor mediated endocytosis
33. In regard to pH
A. pH of a solution is the log to base 10 of the reciprocal hydrogen ion concentration
B. Is the negative log of the concentration of hydrogen ions
C. For each pH unit less than 7 – the concentration of hydrogen ion is increased 10 fold
D. A pH of 7 is equal to a hydrogen ion concentration of 10-7 mmol/l
E. All of the above are true
Correct : E. All of the above are true
34. Regarding heterotrimeric G proteins
A. GDP is bound to the B subunit
B. They are not serpentine receptors
C. The delta unit separates from the other subunits to bring about the biological effect
D. The intrinsic GTPase activity of the alpha subunit converts GTP to GDP
E. They span the membrane seven times
Correct : E. They span the membrane seven times
35. Which of the following is correct?
A. Chloride concentration in interstitial fluid is greater than in the plasma
B. Potassium concentration in interstitial fluid is greater than that in intracellular fluid
C. Sodium concentration in intracellular fluid is greater than in plasma
D. Protein concentration in plasma is greater than in intracellular fluid
E. Bicarbonate concentration in intracellular fluid is greater than in interstitial fluid
Correct : A. Chloride concentration in interstitial fluid is greater than in the plasma
36. Regarding basic physiological measures – all of the following are true EXCEPT
A. Osmolarity is the number of osmoles / litre of solution
B. PH is the log to base 10 of the reciprocal of hydrogen ion concentration
C. Carbon has a molecular mass of 12 dalton
D. Osmolarity is measured by freezing point depression
E. One equivalent of sodium is 23 g/l
Correct : D. Osmolarity is measured by freezing point depression
37. With regards to cell membrane potential
A. The Donnan effect relies on nondiffusible ions
B. The exterior of the cell is negative with respect to the interior
C. The membrane potential tends to push chloride out of the cell
D. It can be derived by measuring the chloride concentration and using the Nernst equation
E. Potassium leaks out against its concentration gradient
Correct : A. The Donnan effect relies on nondiffusible ions
38. Regarding the comparison of ECF with CSF – all of the following are true EXCEPT
A. CSF has less protein
B. CSF has lower osmolality
C. CSF has lower pH
D. CSF has more bicarbonate
E. CSF has lower specific gravity
Correct : B. CSF has lower osmolality
39. Which of the following does NOT act via an intracellular receptor?
A. Cortisol
B. Thyroxine
C. ANP
D. Aldosterone
E. Retinoic acid
Correct : C. ANP
40. 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
Correct : B. Actin is the most abundant protein in mammalian cells