háræðakerfa

Háræðakerfa refers to the smallest blood vessels in the body, forming a network that connects arterioles and venules. These microscopic vessels are crucial for the exchange of oxygen, nutrients, carbon dioxide, and waste products between the bloodstream and the body's tissues. The walls of háræðakerfa are extremely thin, typically consisting of a single layer of endothelial cells, which facilitates efficient diffusion.

There are three main types of háræðakerfa: continuous, fenestrated, and sinusoidal. Continuous háræðakerfa are the most common and have an uninterrupted endothelial lining, found in muscles, lungs, and the central nervous system. Fenestrated háræðakerfa have pores or fenestrations in their walls, allowing for faster passage of small molecules and hormones, and are located in the kidneys and small intestine. Sinusoidal háræðakerfa are the largest and have wider gaps between endothelial cells, enabling the passage of larger molecules, cells, and even blood cells; they are found in the liver, spleen, and bone marrow.

The collective resistance of the háræðakerfa network is high, leading to a significant drop in blood pressure as blood flows through them. This pressure reduction is essential for maintaining the slow flow rate necessary for effective material exchange. The intricate branching pattern of háræðakerfa maximizes the surface area available for this vital process. Disruptions to háræðakerfa function can have serious health consequences, impacting tissue oxygenation and waste removal.