During the passage of blood through a tissue with normal metabolism, the percentage of hemoglobin that unloads oxygen is approximately:

1.	10%	2.	25%
3.	50%	4.	75%

Which of the following is applicable to a change in the affinity of hemoglobin for oxygen?
1. Decreased in rapidly metabolizing tissues
2. Increased at higher than normal body temperatures
3. Increased at higher than normal blood 2,3-DPG levels
4. Decreased at more basic than normal blood pH

What is the number of lobes in the right and the left lungs respectively?

During expiration, the diaphragm and external intercostal muscles are:

1. contracted

2. relaxed

3. flexed

4. both relaxed (diaphragm) and flexed (intercostal muscles)

The respiratory center in humans can be primarily stimulated by:
1. carbon dioxide and hydrogen ions
2. oxygen gas levels in the blood
3. oxygen gas levels in the hemoglobin
4. conscious feeling for the need for more oxygen

The peripheral chemoreceptors in carotid and aortic bodies respond to:
1. hydrogen ion concentration.
2. levels of carbon dioxide in the blood.
3. levels of oxygen in the blood.
4. all of the above

What will happern to the rate and depth of breathing when blood carbon dioxide rises?

Both carbon dioxide and oxygen move across the respiratory membrane due to:

With respect to the atmospheric air, the deoxygenated blood flowing into lung capillaries has a higher concentration of:

Why would hemoglobin deliver oxygen to the tissues?
1. oxygen concentration of tissue fluid is lower
2. carbon dioxide concentration of tissue fluid is lower
3. carbon dioxide concentration of tissue fluid is higher
4. the oxygen concentration of blood is lower