Question

How ADH increases blood pressure?
a. Hyposecretion of ADH leads to low water absorption.
b. Hypersecretion of ADH leads to low water absorption.
c. Hyposecretion of ADH leads to higher water absorption.
d. None of the above.

Answer 1

Antidiuretic Hormone (ADH) is a hormone that controls the amount of water that is absorbed by the kidneys. The more the water absorbed, the less the urine produced and vice-versa. This in turn regulates the blood pressure. It is also a vasoconstrictor, which means that at high concentrations it can constrict the blood vessels.

Complete answer:
- The antidiuretic hormone plays a major role in controlling the blood pressure of a person.
- ADH is produced by the hypothalamus and it triggers the kidneys to absorb water from the blood that is passing through it.
- The more the level of ADH in our body, the more the water absorbed. When more water is absorbed by the kidneys, the urine that is produced is highly concentrated. This is because the water re-enters the bloodstream, thereby increasing the volume of blood. When the volume of blood increases, the blood pressure also increases.
- This means that hypersecretion of ADH leads to higher water absorption by the kidneys.
- High levels of ADH can cause blood vessels to constrict, thereby increasing the pressure of blood.
- When there is hyposecretion of ADH, less water is absorbed by the kidneys. The urine produced is diluted. Since there is a decrease in the volume of blood, the blood pressure also decreases.
- Low levels of ADH can cause the blood vessels to dilate, thereby decreasing the pressure of blood.

Hence, the correct answer is option (B).

Note: Increased levels of ADH in the body can be associated with leukemia, lung cancer, multiple sclerosis, epilepsy, etc. Decreased levels of ADH in the body can be associated with diabetes insipidus, polyuria, alcohol intoxication, and polydipsia. Certain osmoreceptors and baroreceptors trigger the release of the Antidiuretic Hormone from the hypothalamus.