Concept
Version 7
Created by Boundless
Arteries, Veins, and Capillaries
Blood vessel layers
Arteries and veins consist of three layers: an outer tunica externa, a middle tunica media, and an inner tunica intima. Capillaries consist of a single layer of epithelial cells, the endothelium tunic (tunica intima).
Source
Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:
"OpenStax College, Mammalian Heart and Blood Vessels. October 17, 2013."
http://cnx.org/content/m44805/latest/Figure_40_03_07.jpg
OpenStax CNX
CC BY 3.0.