Capillaries as Exchange Vessels

This set of flashcards covers essential terms and definitions associated with the structure and function of capillaries and capillary beds.

Capillary

The smallest type of blood vessel, allowing for exchange of materials between blood and tissues.

Tunica intima

The innermost layer of a capillary composed of a thin layer of endothelial cells.

Pericytes

Spider-shaped contractile stem cells that stabilize capillary walls and regulate permeability.

Microcirculation

The flow of blood from an arteriole to a venule through a capillary bed.

Precapillary sphincters

Muscle cuffs that regulate blood flow into the capillaries.

Intercellular clefts

Gaps between endothelial cells in capillaries that allow the passage of fluids and small solutes.

Continuous capillaries

Type of capillary with uninterrupted endothelial cells and tight junctions, allowing for selective permeability.

Fenestrated capillaries

Capillaries with pores in their walls for increased permeability, typically found in organs that require rapid exchange.

Sinusoidal capillaries

Leaky capillaries with larger gaps and fewer tight junctions, facilitating the movement of larger molecules.

Capillary bed

An interweaving network of capillaries supplying blood to a specific area.