Gas exchange

Question 1

How do different organs function in gas exchange?

Answer 1

Gills promote countercurrent exchange of oxygen to maximize diffusion. Spiracles in insects bring gases directly to cells through tracheae. Lungs facilitate oxygen diffusion into the blood using alveoli.

Question 2

How do avian and mammalian lungs differ?

Answer 2

Avian gas exchange requires multiple air sacs and lungs which function dynamically using cross-current exchange to promote the greatest possible oxygen absorption. Mammalian lungs function less efficiently using negative pressure ventilation and the diaphragm to expand lungs.

Question 3

How do mammals control blood oxygen levels?

Answer 3

The medullary respiratory rate establishes a breath rate. Carbon dioxide (and carbonic anhydrase) and pH levels in the blood activate or inhibit its activity.

Question 4

How are oxygen and carbon dioxide transported by the blood?

Answer 4

Hb carries oxygen using cooperative binding to increase the percentage of oxygen that is delivered to the tissues. CO2 diffuses from tissue to blood and is transported in blood plasma as bicarbonate.

Question 5

Describe the importance of the Bohr shift.

Answer 5

Hb releases oxygen, binds the protons that are released by carbonic anhydrase, thereby increasing the pH until bicarbonate can be converted back into CO2 and diffuse out of the blood.

Question 6

Erythropoietin (EPO)

Answer 6

triggers the production of red blood cells