Kapilleri

Kapilleri, also known as capillaries, are the smallest blood vessels in the circulatory system. They serve as the primary sites for the exchange of gases, nutrients, and waste products between blood and body tissues. Capillaries are characterized by their thin walls, which typically consist of a single layer of endothelial cells. This structural feature facilitates efficient diffusion of substances across the vessel walls.

The diameter of capillaries ranges from about 5 to 10 micrometers, making them significantly smaller than other blood vessels like arteries and veins. Their surface area is extensive, resulting in a dense network that permeates nearly all tissues in the body. Capillary networks are highly adaptable, with the density varying depending on tissue metabolic needs; for example, muscles and the brain have dense capillary beds to meet high oxygen demands.

Capillaries connect arterioles (small arteries) to venules (small veins), forming a communication pathway within the microcirculation. They play a crucial role in maintaining tissue homeostasis by regulating blood flow and facilitating the exchange processes. The permeability of capillary walls is controlled by various factors, including the type of tissue and physiological conditions, allowing selective transfer of substances.

Capillaries also participate in immune responses, allowing immune cells to access tissues and respond to infection or injury. Their structure and function are vital for overall circulatory efficiency and systemic health. Disruptions or damage to capillaries can contribute to various medical conditions, such as hypertension, edema, and diabetic microangiopathy. Due to their essential role, capillaries are a focus of research in fields related to vascular biology, medicine, and biomimicry.