Lümfkapillaarid

Lümfkapillaarid are tiny, dead-end vessels that form a crucial part of the lymphatic system. They are found throughout the body, in most tissues and organs, except for avascular tissues like cartilage and the central nervous system. These capillaries are distinguished by their unique structure, which allows for the efficient collection of interstitial fluid, also known as lymph.

Unlike blood capillaries, lümfkapillaarid have a discontinuous or overlapping endothelial layer. The edges of these endothelial cells overlap, forming flap-like valves. These valves open inwards when the pressure in the interstitial space is higher than inside the capillary, allowing fluid and larger molecules like proteins and fats to enter. When the pressure inside the capillary is higher, the valves close, preventing backflow. This one-way valve system is essential for directing the flow of lymph towards larger lymphatic vessels.

The primary function of lümfkapillaarid is to absorb excess interstitial fluid that has not been reabsorbed by blood capillaries. This fluid, along with waste products, cellular debris, and pathogens, is collected and transported through the lymphatic system. The collected fluid is crucial for maintaining fluid balance in the body and for the immune system's surveillance. Lymphatic capillaries also play a role in absorbing fats from the digestive system, transporting them to the bloodstream. Without the function of lümfkapillaarid, fluid would accumulate in tissues, leading to edema, and the body's ability to fight infection would be severely compromised.