Question

Which of the following are lacking fully formed smooth muscle layers in the tunica medulla?

A) capillaries and small venules

b) capillaries and arterioles

c) capillaries and veins

d) venules and veins

Answer 1

ans A. Capillaries and Small venules

There are 5 types of blood vessels

a. Arteries

b. Arterioles

c. Capillaries

d. Veins

e. Venules

Arteries and Vein have three layers

1. Tunica intima --- Inner layer, made by simple squamous epithelium surrounded by subendothelial connective tissue

2. Tinica media - thickest layer in arteries, rich in vascular smooth muscles (arteies > vein)

Smooth musclecontrols the caliber of vessel.

Tunica adventitia -- Outer most layer, thickest layer in vein, made of only connective tissue.

Capillaries - they are formed by single layer of endothelium, surrounded by pericytes. Capllaries do not have smooth muscle.

Arteioles - Small diamete blood vessel that branches out from artery and lead to capillary. They are site of vascular resistance

Venules - small blood vessel that allow blood to return from the capillary bed to drain into large vein.

3 layers - Endothelium, middle layer of muscle and elastic tissue, outer layer of fibrous connective tissue.

Small endothelial venules are made up of single layer of endothelium