Question

Which of the below describe external and internal respiration?

A. air entering lungs and gas exchange across the lungs
B. Oxygen moving one way across lung tissues and carbon dioxide moving the other way.
C. Gas exchange in the lungs and gas exchange in the systemic tissues of the body, respectively.
D. Breathing through the mouth and nose, respectively.

Answer 1

External respiration occurs in the alveoli of the lungs, while internal respiration takes place in the body tissues. During external respiration, oxygen enters the bloodstream and carbon dioxide is released in the alveoli. In internal respiration, oxygen is released into the tissues and carbon dioxide is picked up.

Step-by-step explanation:

External respiration refers to the exchange of gases with the external environment and occurs in the alveoli of the lungs. Internal respiration, on the other hand, involves the exchange of gases with the internal environment and happens in the tissues of the body.

For example, during external respiration, oxygen from the inhaled air diffuses across the respiratory membrane in the alveoli and enters the bloodstream, while carbon dioxide from the blood diffuses into the alveoli to be exhaled.

During internal respiration, oxygen from the bloodstream diffuses out of the capillaries and into the cells of the body tissues, where it is used for cellular respiration. At the same time, carbon dioxide, as a waste product of cellular respiration, diffuses out of the cells, into the capillaries, and then back into the bloodstream to be transported to the lungs for exhalation.