Drainage of Excess Tissue Fluid into Lymph Ducts
The lymphatic system plays a crucial role in draining excess tissue fluid, also known as interstitial fluid, from tissues and returning it to blood circulation.
Definition
Lymphatic system
A network of vessels, tissues, and organs that work together to drain excess tissue fluid and return it to the blood, while also aiding immune function.
Tissue Fluid and the Lymphatic System
- Capillaries leak plasma, forming tissue fluid, which delivers oxygen and nutrients to cells.
- Most tissue fluid is reabsorbed, but about 3 liters per day remains in tissues.
- Without removal, this excess fluid would cause swelling (oedema).
- The lymphatic system drains excess fluid via lymph ducts, returning it to the blood.
Lymphatic Vessels: Structure for Efficient Drainage
Thin Walls & Gaps for Easy Entry
- Lymphatic vessels have thin, permeable walls made of endothelial cells.
- Gaps between cells act as one-way flaps, allowing fluid in but not out.
- Blind-ended structure ensures fluid moves into the vessel and doesn’t escape.
The permeability of lymphatic vessels, due to their thin walls and gaps, makes them highly effective at collecting excess tissue fluid and preventing swelling.
Valves: Keeping Lymph Moving in One Direction
Definition
Lymph
Lymph is a clear, watery fluid that moves through the lymphatic system and carries nutrients, white blood cells, and other substances throughout the body.
