Brain, mouse - TEM

This 1978 transmission electron micrograph (TEM) depicted a cross-sectional view of a normal, uninfected mouse brain capillary that has been perfusion-fixed at normal blood pressure. The endothelial layer is actually the epithelial layer that lines the lumina of blood vessels, and is comprised of a single layer of endothelial cells. In the case of capillaries, the vessel is made up of an endothelial layer, which is surrounded by a basement membrane, and it's through these very thin-walled vessels that gas exchange, and waste removal takes place.

Image source and content provider: CDC/ Dr. Ed Ewing