Question

Which of the following layers is thicker in arteries than the veins?

• A. Tunica externa
• B. Tunica media
• C. Tunica interna
• D. Tunica adventitia

Answer 1

The correct option is B Tunica media

The walls of arteries and veins consist of three layers: tunica externa, tunica media and tunica interna.
Tunica media is the middle layer which is formed by circular non-striated muscles and a network of elastin fibres. It is thicker in arteries than the veins which make the arteries non-collapsible.

Tunica externa is the outermost layer of arteries and veins which is made up of loose connective tissues having many collagen and elastin fibres with some longitudinal muscles. This layer is also called tunica adventitia.

Tunica interna (also known as tunica intima) is the innermost layer which consists of two parts: elastic membrane and endothelium. The elastic membrane is made up of elastic tissue of yellow fibres. The endothelium is the innermost layer made up of flattened squamous epithelial cells which lines the lumen.