Kapillaarvõrgustiku

Kapillaarvõrgustik is the Estonian term for capillary network. Capillaries are the smallest blood vessels in the circulatory system, forming a vast network throughout the body's tissues and organs. Their primary function is to facilitate the exchange of substances between the blood and the surrounding cells. This exchange includes delivering oxygen and nutrients to the cells and removing carbon dioxide and waste products.

The structure of capillaries is ideally suited for this role. They have very thin walls, typically only one cell thick, which allows for efficient diffusion of gases and molecules. This thinness also means that red blood cells, which are slightly larger than capillaries, must often squeeze through in single file. This slow passage further optimizes the time available for exchange.

The capillary network is incredibly extensive, with estimates suggesting that if all the capillaries in a human body were laid end to end, they would stretch for tens of thousands of miles. This vast surface area is crucial for meeting the metabolic demands of all the body's cells. The regulation of blood flow through the capillary network is a complex process involving precapillary sphincters, which can constrict or relax to control the amount of blood entering specific capillary beds based on the metabolic needs of the local tissues. Disruptions to the capillary network can have significant health consequences, affecting nutrient delivery and waste removal.