Which of the following statements accurately compares external and internal respiration?
A External respiration takes place between the systemic blood vessels and the body’s tissue cells.
whereas internal respiration takes place between the alveoli and the pulmonary blood vessels..
B External respiration takes place between the alveoli and the systemic blood vessels, whereas internal respiration takes place between the pulmonary blood vessels and the body’s tissue cells.
C External respiration takes place between the alveoli and the pulmonary blood vessels, whereas internal respiration takes place between the systemic blood vessels and the body’s tissue cells.
D External respiration takes place between the pulmonary and systemic blood vessels, whereas internal respiration takes place between the alveoli and the body’s tissue cells.
The correct answer and explanation is :
The correct answer is:
C. External respiration takes place between the alveoli and the pulmonary blood vessels, whereas internal respiration takes place between the systemic blood vessels and the body’s tissue cells.
Explanation:
Respiration is the process of gas exchange in the body, and it consists of two major types: external respiration and internal respiration. These two processes facilitate the movement of oxygen (O₂) into the body and the removal of carbon dioxide (CO₂).
External Respiration
External respiration occurs in the lungs, specifically between the alveoli (tiny air sacs) and the pulmonary blood vessels (capillaries of the lungs). This process allows for the exchange of gases between the external environment and the bloodstream. Oxygen from inhaled air diffuses across the thin walls of the alveoli into the pulmonary capillaries, where it binds to hemoglobin in red blood cells. Simultaneously, carbon dioxide, which has been carried in the blood from body tissues, diffuses from the blood into the alveoli and is expelled during exhalation.
Internal Respiration
Internal respiration occurs within body tissues, where oxygen is delivered to cells and carbon dioxide is removed. This process takes place between the systemic blood vessels (capillaries) and the body’s tissue cells. Oxygen-rich blood from the lungs is transported through the systemic circulation to reach tissues. Oxygen diffuses from the blood into the cells, where it is used in cellular respiration to generate ATP (energy). At the same time, carbon dioxide, a waste product of metabolism, diffuses from the cells into the blood, where it is carried back to the lungs for removal.
Thus, external respiration deals with gas exchange between the lungs and blood, while internal respiration deals with gas exchange between blood and body tissues.