81.  Which of the following will cause a decrease in the surface area of the respiratory membrane?  
A.  emphysema
B.  tuberculosis
C.  pneumonia
D.  All of the choices will reduce surface area of the respiratory membrane

82.  Normally, the partial pressure of oxygen gas is higher in the  
A.  blood of the pulmonary capillaries.
B.  bronchioles.
C.  alveoli.
D.  venous blood.

83.  Increasing ventilation will increase the PO₂ and decrease the PCO₂, which promotes gas exchange.  
TRUE

84.  Which of the following results in an increase in shunted blood (blood not completely oxygenated)?  
A.  exercise
B.  pulmonary edema
C.  increased heart rate
D.  increased respiration rate
E.  None of these choices is correct.

85.  As the result of an asthmatic attack,  
A.  ventilation exceeds the ability of blood to pick up oxygen.
B.  ventilation is inadequate to oxygenate blood.
C.  pulmonary blood flow is reduced while ventilation remains normal.
D.  the surface area available for gas exchange increases.
E.  bronchioles dilate.

86.  Arrange the following in order from highest to lowest PO₂.
(1) PO₂ of pulmonary veins
(2) PO₂ of pulmonary artery
(3) PO₂ of alveolar air  
A.  1, 2, 3
B.  2, 1, 3
C.  2, 3, 1
D.  3, 1, 2
E.  3, 2, 1

87.  Oxygen diffusion from the alveolus to the pulmonary capillary occurs because  
A.  alveolar PO₂ is greater than capillary PO₂.
B.  oxygen diffuses faster than carbon dioxide.
C.  alveolar PCO₂ is greater than capillary PCO₂.
D.  alveolar PO₂ is less than capillary PCO₂.
E.  carbon dioxide diffuses faster than oxygen.

88.  In which of the following sequences does PO₂ progressively decrease?  
A.  body tissue, arterial blood, alveolar air
B.  body tissue, alveolar air, arterial blood
C.  blood in aorta, atmospheric air, body tissues
D.  atmospheric air, blood in aorta, body tissues
E.  body tissue, aorta, alveolar air

89.  Oxygen is transported in the blood  
A.  bound to hemoglobin.
B.  bound to albumin.
C.  dissolved in the plasma.
D.  as part of the bicarbonate ion.
E.  dissolved in the plasma and bound to hemoglobin.

90.  During exercise, the oxygen-hemoglobin dissociation curve  
A.  shifts to the right.
B.  shifts to the left.
C.  doesn’t shift.