Question

Each artery and vein consists of three layers: an inner lining of (i) endothelium, the tunica intima, a middle layer of (ii) and (iii) fibres, the tunica media and an external layer of (iv) tissue with (v) fibres, the tunica externa.

• A.

  (i)	(ii)	(iii)	(iv)	(v)
  squamous	smooth muscles	collagen	connective	elastic

• B.

  (i)	(ii)	(iii)	(iv)	(v)
  squamous	smooth muscles	elastic	connective	collagen

• C.

  (i)	(ii)	(iii)	(iv)	(v)
  squamous	connective	collagen	smooth muscles	elastic

• D.

  (i)	(ii)	(iii)	(iv)	(v)
  squamous	connective	elastic	smooth muscles	collagen

Answer 1

Answer: (B)

Basically, each artery and vein consists of three layers: an inner lining of the squamous endothelium, the tunica intima, a middle layer of smooth muscle and elastic fibres, the tunica media, and an external layer of fibrous connective tissue with collagen fibres, the tunica externa. The tunica media is comparatively thin in the veins.