← Chapter 20
Anatomy & Physiology · Chapter 20

Blood Vessel Structure

The wall of an artery or vein is built in three layers — called tunics — wrapped around a hollow center. Tap each layer from the inside out.

Lumen

cross-section · inner → outer
Vessel structurethree tunics

The layers

📷 Reference image
A real labeled figure to compare with the interactive above.
Blood Vessel Structure reference figure
Blood Vessel Structure — OpenStax, CC BY 3.0 (via Wikimedia Commons)