hajszálerek

Hajszálerek, also known as capillaries, are the smallest blood vessels in the body. They form a dense network that connects arterioles (small arteries) and venules (small veins), facilitating the exchange of vital substances between the blood and tissues. Their incredibly thin walls, often only a single layer of endothelial cells thick, are crucial for this function. This thinness allows for the efficient diffusion of oxygen, nutrients, hormones, and antibodies from the blood into the surrounding cells, while simultaneously enabling the removal of carbon dioxide and waste products.

The diameter of a capillary is so narrow that red blood cells must often pass through in single file. This proximity to the vessel walls maximizes the surface area available for exchange. Capillary beds are found in virtually every tissue and organ, with the density varying depending on the metabolic activity of the area. Highly active tissues like muscles and the brain have extensive capillary networks to meet their high oxygen and nutrient demands. The pressure within capillaries is relatively low compared to arteries, which helps prevent damage to their delicate structure and allows sufficient time for effective exchange. This intricate network is essential for maintaining cellular function and overall physiological homeostasis.