endotelvägg

Endothelium is a single layer of cells that lines the interior surface of blood vessels and lymphatic vessels. It plays a crucial role in maintaining vascular health and regulating blood flow. The endothelium is composed of endothelial cells, which are characterized by their flat shape and the presence of cell junctions that allow for the passage of small molecules while preventing the leakage of larger ones.

The primary functions of the endothelium include:

1. **Vasomotor Control**: Endothelial cells release and respond to various vasoconstrictors and vasodilators, such as nitric oxide, endothelin, and prostaglandins, which regulate blood vessel diameter and thereby control blood pressure and flow.

2. **Coagulation and Thrombosis**: The endothelium produces and regulates the activity of proteins involved in blood clotting, such as tissue factor and thrombomodulin. It also synthesizes and releases anticoagulants like tissue plasminogen activator and thrombomodulin, which help prevent excessive blood clotting.

3. **Barrier Function**: The endothelium acts as a selective barrier between the blood and the underlying tissue, preventing the leakage of plasma proteins and other large molecules into the interstitial space.

4. **Immune and Inflammatory Response**: Endothelial cells interact with the immune system, participating in the regulation of inflammation and immune responses. They express adhesion molecules that facilitate the recruitment of immune cells to sites of infection or injury.

5. **Angiogenesis**: The endothelium is involved in the process of angiogenesis, the formation of new blood vessels from preexisting ones. This process is essential for wound healing, embryonic development, and tumor growth.

Disruptions in endothelial function are associated with various pathological conditions, including hypertension, atherosclerosis, diabetes, and inflammation. Maintaining the health of the endothelium is therefore crucial for overall cardiovascular health.