Anatomy and Physiology II Practice Test

What is the primary function of arterioles in the circulatory system?

1. Transport oxygen

2. Regulate blood pressure

3. Filter blood

4. Store blood

The correct answer is: Regulate blood pressure

The primary function of arterioles in the circulatory system is to regulate blood pressure. Arterioles are small blood vessels that branch off from arteries and lead to capillaries. They play a crucial role in controlling blood flow to various tissues by adjusting their diameter through constriction and dilation. This ability to change their size affects peripheral resistance, which in turn influences blood pressure. When arterioles constrict, they increase resistance to blood flow, which can raise blood pressure. Conversely, when they dilate, resistance decreases, leading to a drop in blood pressure. This regulation is essential for maintaining homeostasis and ensuring that different tissues receive adequate blood supply according to their metabolic needs. In contrast, the other functions listed—such as transporting oxygen, filtering blood, and storing blood—are primarily performed by other components of the circulatory system. For instance, oxygen transport is mainly the function of red blood cells within larger blood vessels, while filtration occurs in the kidneys and storage can occur in organs like the spleen.