How are gases exchanged during external respiration and internal respiration?

Asked by Neeti | 31st Dec, 2017, 10:00: PM

Expert Answer:

External respiration is the exchange of gases with the external environment and occurs in the alveoli of the lungs. Internal respiration is the exchange of gases with the internal environment and occurs in the tissues. The exchange of gases occurs due to simple diffusion.Energy is not required to move oxygen or carbon dioxide across membranes. Instead, these gases follow pressure gradients that allow them to diffuse. 
 
During Internal Respiration

The capillaries of the cardiovascular system deliver oxygen-rich  blood to the tissues of the body. Oxygen then diffuses across the thin capillary walls from the high concentrations in the blood to the low concentrations in the tissues. At the same time, carbon dioxide that has been produced as a waste product by the tissues diffuses through the thin capillary walls into the blood where it is transported back to the alveoli.

During External Respiration

Oxygen from the inhaled air is diffused into the alveoli in the lungs and the waste product carbon dioxide from the body diffuses out through the alveoli to be exhaled back into the air. With the help of the cardiovascular system, the freshly inhaled oxygen-rich blood is transported to the tissues of the body.

Answered by Sivanand Patnaik | 1st Jan, 2018, 08:35: AM