Arterial Wall Composition

Steps:

• Recall artery structure: three layers—tunica intima, media, and externa.
• Tunica intima includes endothelium for inner lining.
• Tunica media contains smooth muscle and elastic tissue for contraction and recoil.
• Tunica externa has collagen fibers for strength and support.

Why A is correct:

• Arteries consist of endothelium (intima), smooth muscle and elastic tissue (media), and collagen fibers (externa), as defined in vascular histology.

Why the others are wrong:

• B omits collagen fibers, which provide structural integrity in the outer layer.
• C lists only collagen fibers, ignoring endothelium, muscle, and elastic components essential for artery function.
• D is incomplete and provides no valid components.

Final answer: A