endothelium
The thin cellular layer that lines the interior surface of blood vessels and lymphatic vessels.
Full Definition
The endothelium is a single layer of squamous epithelial cells that forms the innermost lining of blood vessels, lymphatic vessels, and the heart chambers. This cellular barrier plays crucial roles in vascular function including regulation of vascular tone, coagulation, inflammation, and permeability. Endothelial cells produce various bioactive substances including nitric oxide, prostacyclin, and endothelin, which regulate blood flow and vascular homeostasis. Endothelial dysfunction is recognized as an early marker of cardiovascular disease and plays a key role in the pathogenesis of atherosclerosis, hypertension, and other vascular disorders.
Usage
Usage note: Adjective form is 'endothelial'.
In Context
- "Endothelium-dependent vasodilation was impaired in patients with diabetes mellitus." — Vascular function study
- "The damaged endothelium exhibited increased permeability to inflammatory cells." — Pathology report