What is the Role of Capillaries in the Vascular System?
Capillaries are the smallest blood vessels and the primary sites for the exchange of gases, nutrients, and waste products between blood and tissues. They consist of a single layer of endothelial cells and a basement membrane. Capillaries can be classified into: - Continuous capillaries: Found in most tissues, with tight junctions between endothelial cells. - Fenestrated capillaries: Contain pores (fenestrations) that allow for increased permeability, found in the kidneys, intestines, and endocrine glands. - Sinusoidal capillaries: Have large gaps between endothelial cells, allowing for the passage of larger molecules and cells, found in the liver, spleen, and bone marrow.
