Kapillaarilumen

Kapillaarilumen refers to the hollow space within a capillary, which is the smallest type of blood vessel. Capillaries are crucial for the exchange of oxygen, nutrients, carbon dioxide, and waste products between the blood and the body's tissues. The lumen of a capillary is extremely narrow, typically measuring only about 5 to 10 micrometers in diameter. This narrowness is essential because it forces red blood cells, which are about 7-8 micrometers in diameter, to pass through in single file. This single-file arrangement maximizes the surface area of the red blood cells exposed to the capillary wall, facilitating efficient diffusion. The wall of a capillary, called the endothelium, is very thin, usually only one cell thick, which further enhances the speed and ease of this exchange process. The pressure within the capillary lumen is also a significant factor in driving the movement of substances across the endothelial cells and into the surrounding interstitial fluid. Understanding the structure and function of the capillary lumen is fundamental to comprehending microcirculation and its role in maintaining cellular health and homeostasis throughout the body.