Question

question 18
what causes the wavy appearance of the lumen and tunica interna of arteries?
internal elastic membrane of the tunica interna
external elastic membrane of the tunica interna
vasa vasorum
partial smooth muscle constriction of smooth muscle from the tunica media

Explanation:

The internal elastic membrane of the tunica interna is elastic and allows arteries to expand and recoil. When arteries are not fully distended (e.g., during histological preparation when blood pressure is removed), this elastic membrane wrinkles, causing the wavy appearance. The external elastic membrane is part of the boundary between tunica media and tunica externa. Vasa vasorum are small blood vessels that supply the outer part of larger blood vessels. Partial smooth - muscle constriction of the tunica media affects the diameter of the artery but not the wavy appearance of the lumen and tunica interna in the way described.

Answer:

Internal elastic membrane of the tunica interna