Long COVID Atlas
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Plain-language first, with specialist detail below. For understanding, not medical advice.

Long COVID AtlasGlossary › Endothelium

Anatomy

Endothelium

https://longcovidatlas.org/glossary/endothelium

In plain language

What it is

The thin, living layer of cells lining the inside of every blood vessel you have.

Why it matters

It is a body-wide control system for blood flow, so when it stops working the effects show up in many organs at once.

Think of it like

Think of every vessel as a hose whose inner surface is a smart coating that can widen it, tighten it, keep flow smooth, and stop leaks.

For specialists

Formal definition

A single-cell-thick monolayer of endothelial cells lining the lumen of all blood and lymphatic vessels, regulating vasomotor tone, hemostasis, permeability, and leukocyte trafficking.

Mechanism

Endothelial cells release nitric oxide and other mediators to balance vasodilation and vasoconstriction, present anticoagulant surfaces, and gate paracellular and transcellular transport.

Sources

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