What will be the partial pressure of oxygen in a mixture of gases where the total pressure is 500 mmHg and oxygen comprises 20% of the gas mixture?

1. 0.1 mm Hg	2. 10 mm Hg
3. 100 mm Hg	4. 200 mm Hg

All the following changes occur in the circulatory system when a fetus is delivered and begins to breathe on its own for the first time except:
1. the rate of blood flow through pulmonary circulation decreases
2. the foramen ovale closes
3. the ductus arteriosus closes
4. the resistance to blood flow through the lung decreases

“Bends” is a painful condition that is seen in cases of:
1. nitrogen narcosis
2. decompression sickness
3. hyperbaric oxygen therapy
4. carbon dioxide accumulation

Overinflation of lungs can be damaging and is prevented in humans by:
1. apneustic center
2. Hering-Breuer reflex
3. hypercapnia
4. inspiratory neurons

Oxidized hemoglobin is known as:
1. carboxyhemoglobin
2. methemoglobin
3. oxy hemoglobin
4. carbaminohemoglobin

Alveoli are tiny, balloon-shaped air sacs that sit at the very end of the respiratory tree, branching off the _______.

The cells lining the alveoli that secrete the pulmonary surfactant are:
1. type I alveolar cells
2. type II alveolar cells
3. filtration from the alveolar capillaries
4. alveolar macrophages

A measure of the amount of air a person inhales during a normal breath is:

2,3-diphosphoglycerate in red blood cells:
1. enhances oxygen unloading at the systemic capillaries
2. makes deoxyhemoglobin less stable
3. shifts the oxyhemoglobin dissociation curve to the left
4. stimulates the production of more red blood cells

Four globin chains [ 2 alpha and 2 gamma] constitute the structure of:
1. hemoglobin A
2. hemoglobin F
3. hemoglobin S
4. methemoglobin