The exchange of gases between lungs and blood is :

Question

Accepted Answer

The exchange of gases between the lungs and blood is referred to as "External Respiration." This process is crucial for maintaining the body's oxygen supply and removing carbon dioxide, a waste product of metabolism. Here's a detailed explanation of why Option 1 is correct and why the other options are incorrect:

1. **External Respiration (Correct Answer):**
   - External respiration specifically refers to the exchange of gases between the alveoli in the lungs and the blood in the pulmonary capillaries. During this process, oxygen from the inhaled air diffuses across the alveolar membrane into the blood, while carbon dioxide from the blood diffuses into the alveoli to be exhaled. This gas exchange is driven by differences in partial pressures of oxygen and carbon dioxide between the alveoli and the blood. External respiration is a critical step in ensuring that oxygen is delivered to the bloodstream and carbon dioxide is expelled from the body.

2. **Pulmonary Ventilation (Incorrect):**
   - Pulmonary ventilation, also known as breathing, is the process of moving air into and out of the lungs. It involves the mechanical act of inhalation and exhalation, which facilitates the movement of air containing oxygen into the lungs and the removal of air containing carbon dioxide from the lungs. However, pulmonary ventilation does not involve the actual exchange of gases between the lungs and the blood; it merely provides the air necessary for external respiration to occur.

3. **Internal Respiration (Incorrect):**
   - Internal respiration refers to the exchange of gases between the blood and the body's tissues. In this process, oxygen diffuses from the blood into the cells, and carbon dioxide diffuses from the cells into the blood. Internal respiration occurs at the cellular level and is distinct from external respiration, which occurs in the lungs. Therefore, internal respiration is not the correct term for the exchange of gases between the lungs and blood.

4. **Cellular Respiration (Incorrect):**
   - Cellular respiration is a metabolic process that occurs within cells, where oxygen is used to produce energy in the form of ATP (adenosine triphosphate) from glucose, and carbon dioxide is produced as a byproduct. This process takes place in the mitochondria of cells and is not related to the exchange of gases between the lungs and blood. Cellular respiration is a separate process that follows the delivery of oxygen to the cells via the bloodstream.

In summary, external respiration is the correct term for the exchange of gases between the lungs and blood, as it specifically describes the process occurring in the alveoli where oxygen is absorbed into the blood and carbon dioxide is released into the lungs.