Peripheral vascular resistance

Definition

Peripheral vascular resistance (PVR) is the resistance that must be overcome to push blood through the peripheral circulatory system. It is a major determinant of arterial blood pressure and is influenced by vessel diameter, blood viscosity, and vessel length.

5 Must Know Facts For Your Next Test

1. PVR is directly related to the diameter of blood vessels; vasoconstriction increases PVR while vasodilation decreases it.
2. Antihypertensive drugs like ACE inhibitors and calcium channel blockers work by reducing PVR.
3. High PVR can lead to hypertension, which increases the risk of cardiovascular events such as heart attacks and strokes.
4. PVR plays a crucial role in determining afterload, which affects cardiac workload and oxygen demand.
5. Factors such as sympathetic nervous system activity, hormones like angiotensin II, and endothelial function influence PVR.

Review Questions

• How does vasoconstriction affect peripheral vascular resistance?
• Which class of antihypertensive drugs works by decreasing peripheral vascular resistance?
• What are some factors that can increase peripheral vascular resistance?

Related terms

Afterload: The pressure that the heart must work against to eject blood during systole.

Vasodilation: The widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls.

Angiotensin II: A hormone that causes blood vessels to constrict, leading to an increase in blood pressure.