Lymph capillary

Lymph Capillary

Diagram of a lymph capillary

Lymph capillaries, also known as lymphatic capillaries, are tiny, thin-walled vessels located in the spaces between cells throughout the body, except in the central nervous system and non-vascular tissues. They are a crucial component of the lymphatic system, which is part of the immune system and plays a vital role in maintaining fluid balance in the body.

Structure

Lymph capillaries are composed of a single layer of endothelial cells that overlap each other, forming flap-like minivalves. These minivalves open to allow interstitial fluid to enter the capillary when the pressure in the interstitial space is greater than the pressure inside the capillary. This unique structure enables the lymph capillaries to absorb large molecules, such as proteins and lipids, that cannot be absorbed by blood capillaries.

Function

The primary function of lymph capillaries is to collect excess interstitial fluid from tissues and transport it to larger lymphatic vessels. This fluid, now called lymph, is eventually returned to the bloodstream. By doing so, lymph capillaries help maintain fluid balance in the body and prevent edema, which is the accumulation of excess fluid in tissues.

Lymph capillaries also play a role in the immune response. They transport antigens and dendritic cells to lymph nodes, where an immune response can be initiated. This process is essential for the body's defense against infections and diseases.

Location

Lymph capillaries are found throughout most of the body, with the exception of the central nervous system, bone marrow, and avascular tissues such as the epidermis and cartilage. They are particularly abundant in tissues that are prone to fluid accumulation, such as the dermis of the skin and the mucous membranes of the respiratory and digestive tracts.

Related Pages

• Lymphatic system
• Immune system
• Lymph node
• Interstitial fluid
• Edema