Exchange of Gases in the lungs
Step-by-step explanation:
- Gas exchange occurs by process of diffusion.
- Gas exchange occurs in sac like structures called alveoli.
- Oxygen diffuses from the alveolar sacs into the blood in the capillaries.
- Carbon dioxide diffuses from the blood in the capillaries into the alveolar sac .
As blood passes through the lungs, it picks up oxygen and gives up carbon dioxide simply by diffusion down partial pressure gradients between blood and Alveoli,.
The blood having returned from body is relatively low in oxygen and high in carbon dioxide. On the other hand the alveolar air has higher oxygen concentration and lower carbon dioxide concentration.
Thus, when venous blood flows through pulmonary capillaries, oxygen moves from alveoli into the capillaries while carbon dioxide flows from capillaries into the alveoli.