811. Regarding isometric ventricular relaxation
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 A V valves open

812. Local vasoconstriction results from
A. Increased potassium concentration
B. Increased magnesium concentration
C. Increased sodium concentration
D. Decrease in pH
E. Increased calcium concentration

813. With regard to ascending to high altitudes
A. There is a linear decrease in inspired oxygen pressure with increasing altitude
B. The partial pressure of water vapour in moist inspired air decreases with P]02
C. At 19 200 m, barometric pressure = 47 mmHg, P]02 then is approx. 9 mmHg
D. At peak at Mt Everest, barometric pressure = 3S0 mmHg, P]02 there is approx. 70 mmHg
E. In permanent residents of the Andes, arterial and venous P02 is half normal levels lOS.

814. Which of the following has the greatest effect on the ability of the blood to transport oxygen
A. The capacity of the blood to dissolve oxygen
B. The amount of Hb in the blood
C. The pH of the plasma
D. The C02 content of red blood cells
E. The temperature of the blood

815. The Haldane effect describes
A. The shift to the right of the oxygen dissociation curve caused by increased PC02
B. The enhanced loading of C02 in the presence of deoxygenated Hb
C. The shift of chloride ions into red blood cells to balance HC03 shift from those cells
D. The action of carbonic anhydrase on carbonic acid
E. None of the above

816. With regard to C02 carriage in the blood
A. Dissolved C02 has an insignificant role in the carriage of C02 in the blood
B. HC03 production is fast in plasma
C. Ionic dissociation of carbonic acid in the red cell is fast without an enzyme
D. The C02 concentration in blood is independent of the saturation ofHb with oxygen
E. The majority of C02 is carried in the blood in the forms of dissolved C02 and carbamino compounds

817. Substances cleared from the circulation by the lungs include all the following except
A. Angiotensin II
B. Serotonin
C. Leukotrienes
D. Bradykinin
E. Prostaglandin

818. With regard to the normal Hb-oxygen dissociation curve, which is the most likely to be correct
A. When arterial P02 = 60 mmHg, Hb saturation is -80%
B. When arterial P02 = 40 mmHg, Hb saturation is -75%
C. When arterial P02 = 30 mmHg, Hb saturation is -40%
D. Acidosis shifts the curve to the left
E. Decreased PC02 shifts the curve to the right

819. 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

820. The following physiological events that occur in the body are listed in random sequence
A. Decreased CSF pH
B. Increased PaC02
C. Increased CSF PC02
D. Stimulation of medullary chemoreceptors
E. Increased P AC02 What is the usual sequence A. 


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