What is included in the process of external respiration Select one: a. Gas exchange at the tissues b. Gas exchange at the lungs c. Transport of gases via the blood d. Production of ATP by cells
The Correct Answer and Explanation is :
The correct answer is b. Gas exchange at the lungs.
Explanation:
External respiration refers to the process of gas exchange that occurs between the environment and the blood, specifically at the lungs. This process involves the exchange of oxygen (O2) and carbon dioxide (CO2) between the air in the lungs and the blood circulating through pulmonary capillaries.
- Gas exchange at the lungs (External Respiration):
Oxygen from the inhaled air diffuses across the thin walls of the alveoli (tiny air sacs in the lungs) into the blood in the surrounding capillaries. At the same time, carbon dioxide, a waste product of cellular metabolism, diffuses from the blood into the alveoli to be exhaled. This exchange occurs due to differences in the partial pressures of these gases in the alveoli and the blood, following the principles of diffusion. - Gas exchange at the tissues (Internal Respiration):
This refers to the exchange of gases between the blood and the tissues, which is separate from external respiration. Oxygen is delivered to the tissues, and carbon dioxide is picked up by the blood from the tissues. - Transport of gases via the blood:
After external respiration, oxygen is transported in the blood, primarily bound to hemoglobin in red blood cells, while carbon dioxide is carried back to the lungs in various forms (such as dissolved in plasma or bound to hemoglobin) for removal during exhalation. This phase is crucial for the delivery and removal of gases but is not part of the external respiration process itself. - Production of ATP by cells:
The production of ATP occurs through processes like cellular respiration within the cells. This process is linked to internal respiration, as oxygen is used to produce ATP and carbon dioxide is generated as a waste product. However, it is not part of external respiration.
Thus, external respiration specifically involves the exchange of gases between the lungs and blood, which makes gas exchange at the lungs the correct answer.