Which of the following hormones constricts the arterioles in the peripheral circulation to reduce blood flow to the extremities and thereby increase blood supply to the core of the body?
ATP
ADH ICF
ECF
ADT
The correct answer and explanation is:
The correct answer is ADH (Antidiuretic Hormone).
Explanation:
ADH, also known as vasopressin, is a hormone produced by the hypothalamus and secreted by the posterior pituitary gland. One of its primary functions is to regulate the body’s water balance by increasing water reabsorption in the kidneys. However, ADH also has a significant role in regulating blood pressure and blood flow.
When blood volume is low, or blood pressure drops, ADH is released into the bloodstream. It acts on the arterioles, causing vasoconstriction, which narrows the blood vessels. This vasoconstriction increases the resistance within the vessels, raising the blood pressure. The effect of this is most significant in peripheral circulation, where blood flow is reduced to the extremities (arms, legs, etc.), thus redirecting more blood to vital organs, especially the core of the body, such as the heart and brain.
This mechanism is part of the body’s effort to maintain homeostasis and ensure that essential organs receive an adequate supply of oxygen and nutrients during times of stress or dehydration. The narrowing of peripheral vessels helps prevent excessive fluid loss and promotes fluid retention by the kidneys, further supporting the maintenance of blood pressure and volume.
ADH’s effects are especially critical during times of severe blood loss or dehydration when the body needs to prioritize blood flow to vital organs. It is also involved in regulating osmolarity, which is the concentration of solutes in the blood. By controlling water reabsorption in the kidneys, ADH helps to balance the body’s fluid levels, ensuring proper hydration and optimal function of various systems.
In summary, ADH constricts peripheral arterioles, reducing blood flow to extremities and ensuring that blood is redirected to the core, which is critical for maintaining vital organ function.