I need some Biology Essay Help?

Question

The world record time for running the mile is just under four minutes. How might this record be different if humans had air sacs like birds do? I need a lengthy explanation please!!!!!

Answer 1

Birds have air sacs attached to their lungs for more air capacity.

If humans had air sacs like birds had we would have better stamina and therefore be able to run faster. The air which birds breathe instead of going directly to the alveoli, first empties out in the air sacs which on filling up contract, allowing the oxygen to be absorbed by the alveoli.

Answer 2

The two primary differences between human and bird respiratory systems are the direction of ventilation  and the gas exchange surfaces.

Gas exchange in mammals is conducted at the alveoli, a respiratory structure in the lungs. Inhaled air, which has a higher partial pressure of oxygen (PO2), passively diffuses through the alveolar capillaries into deoxygenated blood, which has a lower PO2. At the same time, CO2 diffuses from the blood in alveoli capillaries into the air space in the alveloi, following the same passive diffusion principles mentioned above. The CO2 transferred from the capillaries is exhaled. Human ventilation is referred to as being unidirectional; that is, gas exchange only occurs when air is inhaled, not exhaled.

Birds, however, possess unique respiratory structures allowing bidirectional respiration; gas exchange occurring during exhalation and inhalation. In addition to possessing lungs, birds have what are called "air sacs." When birds inhale, O2 exchange occurs across the lungs, just as humans. However, air also flows into the air sacs. When birds exhale, air in the lungs (rich in CO2 and poor in O2) is still exhaled, but air in the air sacs (which is still O2 rich) leaves these air sacs and also passes the lungs.. Thus, in both inhalation and exhalation, birds are able to deliver O2 to their systems.

If a running human had bird respiratory systems, they would be able to deliver O2 to their working muscles during both exhalation and inhalation, allowing more efficient respiration and a higher amount of O2 delivered to their muscles. . Thus, the record would be crushed!

Hope that helps; check out the reference for more specifics.