I = 2 + 3 + 4 + 5 — Tunica intima; 2 — Endothelium; 3 — Basal membrane; 4 — Subendothelial layer; 5 — Internal elastic membrane; 6 = 7 + 8 + 9 — Tunica media; 7 — Myocytus; 8 — Elastic fibres; 9 — Collagen fibers; 10 = 11 + 12 + 13 — Tunica externa;
II — External elastic membrane; 12 — Fibrous (loose) connective tissue; 13 — Blood vessels