Question

In humans, the respiratory center a. is stimulated by carbon dioxide. b. is located in the medulla oblongata. c. controls the rate of breathing. d. All of these are correct.

Short answer

The respiratory center in humans is stimulated by carbon dioxide, located in the medulla oblongata, and controls the rate of breathing. Therefore, all the given statements are correct. The correct answer is d. All of these are correct.

Step-by-step solution

Statement a: Is stimulated by carbon dioxide.

The respiratory center in humans is indeed stimulated by carbon dioxide. When carbon dioxide levels in the blood increase, the respiratory center sends signals to the muscles involved in breathing, such as the diaphragm, to increase the rate of respiration. This helps in expelling excess carbon dioxide from the body.

Statement b: Is located in the medulla oblongata.

The respiratory center is located in the medulla oblongata, a part of the brainstem. The medulla oblongata is responsible for regulating various autonomic functions, including respiration.

Statement c: Controls the rate of breathing.

The respiratory center does control the rate of breathing. By responding to changes in the levels of carbon dioxide and oxygen in the blood, as well as other factors such as physical activity, the respiratory center adjusts the rate and depth of breathing to maintain optimal levels of these gases in the body.

Statement d: All of these are correct.

Considering the analysis of each statement provided above, we can conclude that all of them are correct. The respiratory center is stimulated by carbon dioxide, is located in the medulla oblongata, and controls the rate of breathing. So, the correct answer is: d. All of these are correct.