RESPIRATORY 1. The anatomic dead space a. Varies with minute ventilation b. Is typically 150mL c. Will increase in C.O.P.D d. Is alveolar minus the pathological dead space e. All of the above 2. With regards to pulmonary gas exchange a. Transfer of nitrous oxide is perfusion limited b. Transfer of oxygen is typically diffusion limited c. At altitude the profound systemic hypoxaemia favours oxygen diffusion d. The diffusion rate for CO2 is double that of oxygen e. Diffusion is inversely proportional to the partial pressure gradiant 3. With regard to the distribution of pulmonary blood flow a. Typically there is a zone at the apex that is not perfused b. The mean pulmonary arterial pressure is 8mmHg c. In some areas flow is determined by the arterial/alveolar pressure difference d. Hypoxia leads to pulmonary vasodilation e. The net balance of Starling forces act to keep the alveoli dry 4. At a barometric pressure of 500mmHg and breathing 30% oxygen by a fixed performance system, the alveolar oxygen tension can be calculated as a. 86mmHg b. 95mmHg c. 98mmHg d. 136mmHg e. not enough information 5. The haemoglobin oxygen dissociation curve moves up and to the left with a. Increased hydrogen ion concentration b. Hypothermia c. Increased 2,3 DPG d. Hypercarbia e. All of the above 6. The haldane effect refers to a. The increased capacity for deoxygenated blood to carry CO2 b. The dissociation constant for the bicarbonate buffer system c. The chloride shift that occurs to maintain electrical neutrality d. The carriage of dissolved CO2 according to Henry’s law e. The shape of the CO2 dissociation curve 7. La Place’s law a. Explains the observed elastic recoil of the chest b. Determines the change in volume per unit change in pressure c. Tells us the pressure is inversely related to tension d. Explains the tendency of small alveoli to collapse e. All of the above 8. In control of ventilation the medullary chemoreceptors respond to a. Oxygen tension b. Hydrogen ion concentration c. CO2 tension + d. H concentration and CO2 tension + e. H concentration and oxygen and CO2 tension 9. compliance of the lung is reduced by all of the following except a. emphysema b. alveolar oedema c. fibrosis d. consolidation e. high expanding pressures 10. Pulmonary vascular resistance a. Increases as venous pressure rises b. Is increased in both very low and high lung volumes c. Is decreased by histamine d. Is increased by muscular pulmonary arterioles which regulate blood flow to various regions of the lungs e. Increases with recruitment 11. Regarding pulmonary blood flow a. Low blood pH causes vasodilation b. At high altitude, generalized vasodilation causes a rise in pulmonary arterial pressure c. Vasoconstriction may occur when the alveolar pO2 is reduced below 55mmHg d. Inhaled nitrous oxide reduces pulmonary vasoconstriction e. Endothelins are potent vasodilatory peptides 12. causes of hypoxic hypoxia include all of the following except a. pulmonary shunting b. morphine c. pulmonary fibrosis d. fatigue e. congestive heart failure 13. Regarding buffers of the body a. Initial correction of pH disturbance is best achieved by the kidneys b. The phosphate buffer system is the predominant buffer in the blood c. Bones contribute to the buffer system by taking up HCO3 d. Hb is am important buffer of the blood e. All of the above are correct 14. Regarding ventilation/perfusion differences in the lungs a. In healthy individuals, anatomical dead space is less than physiological dead space b. The relative change in blood flow from apex to base is less than relative change in ventilation c. V/Q differences are due to gravity d. V/Q ratio is low at the bases e. All of the above 15. lung compliance a. is normally 100mL/cm water b. falls if the lung remains unventilated for long periods c. rises if the pulmonary venous pressure is increased d. falls as the lung ages e. is the area under the pressure volume curve 16. work of the lung in breathing a. is increased with larger tidal volumes b. is increased with higher flow rates c. in inspiration need to overcome elastic forces and viscous resistance d. in expiration need to overcome airway and tissue resistance e. all of the above 17. The most important short term response to high altitude is a. Hyperventilation b. Polycythaemia c. Chronic mountain sickness d. Acidosis e. Decreased EPO release 18. Regarding the alveolar gas equation a. It gives the value of alveolar pO2 in a given patient b. R denotes the respiratory rate c. At sea level, pIO2 = 690mmHg x 0.21 of humidified air d. At high altitude, paCO2can be less than 35mmHg e. The alveolar gas equation is only applicable at sea level 19. In CO2 transport a. The HCO3 content of venous blood is reduced compared to arterial blood b. The osmolarity of RBCs in venous blood is increased compared to arterial blood c. The haematocrit of venous blood is 3% less than arterial blood d. The solubility of CO2 in blood is less than O2 e. CO2 does not react with plasma proteins 20. With regard to the neural control of respiration a. There are 3 neural mechanisms regulating respiration b. The dorsal group of respiratory centre has excitatory neurons c. The ventral group of respiratory centre is located in the pons d. The main respiratory control centre is located in the pons e. Voluntary control system is located in the cerebral cortex 21. Surfactant a. Is produced by class II pneumocytes b. Is increased in smokers c. Helps keep the alveoli moist d. Decreases alveolar stability in preterm babies e. Maturation is impaired by glucocorticoids 22. Regarding the O2 dissociation curve a. Each gram of pure Hb can bind 1 mol of O2 b. 2,3 DPG levels fall at high altitude c. an increase in the affinity of Hb for O2 in an acid environment is called the Bohr effect d. a right shift implies a lower pO2 is required for O2 binding e. the p50 is an index of the affinity of Hb for O2 23. for the chemical control of respiration a. the carotid bodies respond to changes in pH, pCO2 and O2 b. the aortic bodies respond to changes in pH, pCO2 and O2 c. pO2 is only detected by central chemoreceptors d. severe hypoxia strongly stimulates central chemoreceptors e. the central chemoreceptors respond to changes in plasma pH 24. With respect to lung volumes a. FRC can be measured with a spirometer b. He dilution measures the total volume of gas in the lung, including any trapped behind closed airways c. The volume of gas left in the lungs after a maximal expiration is the functional residual volume d. Vital capacity is the volume exhaled when a maximal inspiration is followed by a maximal expiration e. TLC is the volume of the lung available to partake in gas exchange 25. Surfactant a. Increases surface tension b. Surface tension is proportional to their concentration c. Is produced by type I alveolar cells d. Is increased in cigarette smoking e. Prevents pulmonary oedema 26. The expected paO2 in mmHg of a person breathing 28% oxygen who has a paCO2 of 50 is a. 88 b. 118 c. 138 d. 150 e. 158 27. Haemoglobin dissociation curve shifts a. To the right with CO poisoning b. To the left with a rise in temperature c. To the left with a rise in pH d. To the right with a decrease in 2,3 DPG e. To the left with anaemia 28. In CO2 transport a. There is slightly more carbon dioxide in dissolved in the blood than oxygen b. Venous blood can carry more CO2 than arterial blood c. Chloride shift allows CO2 to dissociate d. There is equal amounts of CO2 transported as dissolved CO2 and carbamino compounds e. 2,3 DPG concentration in RBC will alter the cells ability to catalyse CO2 29. With respect to gas transport in the blood a. Arterial pO2 measures the amount of oxygen bound to haemoglobin b. Normal arterial blood with a pO2 of 100mHg contains 3mL of dissolved oxygen per litre c. Haldane effect refers to the shift of Chloride ions into the RBC to maintain electrical neutrality after carbon dioxide diffuses out of cells d. The great bulk of carbon dioxide in blood is found as dissolved carbon dioxide and carbamino compounds e. Oxygen capacity is the total amount of oxygen that can be carried in 100mL of blood 30. In regional ventilation and perfusion of the lung a. Upper regions of the lung ventilate better than the lower regions b. When supine the apical and basal ventilation is equal c. V/Q ratio increases down the lung d. The highest alveolar pO2 is at the base of the lung e. Blood flow is uniform throughout the normal lung 31. The main respiratory control neurons a. Send out regular bursts of impulses to expiratory muscles during quiet respiration b. Are unaffected by stimulation of pain receptors c. Are located in the pons d. Send out regular bursts of impulses to inspiratory muscles during quiet respiration e. Are unaffected by impulses from the cerebral cortex 32. With respect to dead space a. Dead space volume is equal to he person’s weight in kg b. For a constant minute ventilation, alveolar ventilation is decreased as respiratory rate increases c. Anatomic dead space is less than physiological dead space in healthy persons d. Physiological dead space is measured by analysis of single breath nitrogen curves e.