Resistance vessels are which type of blood vessel?

Resistance vessels are which type of blood vessel?

• A. Capillaries
• B. Elastic arteries
• C. Arterioles
• D. Venules

Answer: (C)

Arterioles are the resistance vessels. Their small diameter and substantial smooth muscle in the walls let them constrict or dilate to regulate how much blood flows into each capillary bed. Because resistance to flow increases dramatically as radius decreases (Poiseuille’s principle), these tiny vessels are the main determinants of systemic vascular resistance and thus mean arterial pressure. Elastic arteries, by contrast, are large conducting vessels that dampen pulse pressure rather than regulate resistance; capillaries are thin-walled exchange vessels with little smooth muscle; venules and veins are capacitance vessels that store blood at low pressure. So the vessels responsible for controlling resistance and distribution of flow are the arterioles.

Arterioles are the resistance vessels. Their small diameter and substantial smooth muscle in the walls let them constrict or dilate to regulate how much blood flows into each capillary bed. Because resistance to flow increases dramatically as radius decreases (Poiseuille’s principle), these tiny vessels are the main determinants of systemic vascular resistance and thus mean arterial pressure. Elastic arteries, by contrast, are large conducting vessels that dampen pulse pressure rather than regulate resistance; capillaries are thin-walled exchange vessels with little smooth muscle; venules and veins are capacitance vessels that store blood at low pressure. So the vessels responsible for controlling resistance and distribution of flow are the arterioles.