Capillary beds

Definition

Capillary beds are networks of tiny blood vessels where the exchange of gases, nutrients, and waste products occurs between blood and tissues. They connect arterioles and venules and play a crucial role in microcirculation.

5 Must Know Facts For Your Next Test

1. Capillary beds facilitate the exchange of oxygen, carbon dioxide, nutrients, and waste products between blood and tissues.
2. They have thin walls composed of a single layer of endothelial cells to allow easy diffusion.
3. Blood flow through capillary beds is regulated by precapillary sphincters.
4. Capillaries are classified into three types: continuous, fenestrated, and sinusoidal based on their permeability.
5. The extensive surface area of capillary beds ensures efficient nutrient delivery to all body cells.

Review Questions

• What primary function do capillary beds serve in the circulatory system?
• How is blood flow through capillary beds regulated?
• Name the three types of capillaries found in capillary beds.

Related terms

Arterioles:

Small blood vessels that lead into capillary beds from arteries.

Venules: Small blood vessels that drain blood from capillary beds into veins.

Precapillary Sphincters: Rings of smooth muscle that regulate blood flow into capillaries.