Quick Facts
The subendothelial layer is a middle, fibrous layer of the tunica intima of typical blood vessels, located between the endothelium and internal elastic membrane; it also comprises the bulk of the endocardium, where it lies deep to the lining endothelium. It is composed of varying amounts of collagen and elastic fibers and smooth muscle cells (Dorland, 2011).
Related parts of the anatomy
Structure
Within the tunica intima of the artery wall, between the endothelium and internal elastic lamina, is the subendothelial layer.
The subendothelial layer is a thin layer consisting of a single layer of loose connective tissue. This layer also contains some elastic fibers, collagen type I fibrils, fibroblasts, and small smooth muscle cells.
Anatomical Relations
The subendothelial layer lies between the endothelium and internal elastic lamina in the intima of blood vessels.
Function
Cells of the subendothelial layer are contractile, but they also secrete ground substance (an amorphous jelly-like material containing proteoglycans), collagen, and elastic fibers, which assists in compliance of the vessel wall. In addition, macrophages are occasionally present in this layer, scavenging for foreign material and dead cells (Pawlina, 2016).
List of Clinical Correlates
- Atherosclerosis
References
Dorland, W. (2011) Dorland's Illustrated Medical Dictionary. 32nd edn. Philadelphia, USA: Elsevier Saunders.Pawlina, W. 2016. Histology: A text and atlas with correlated cell and molecular biology. 7th ed. Philadelphia: Wolters Kluwer.
