Question

The correct sequence of layers found in the walls of arteries from inside to outward is?
a. Tunica adventitia, tunica interna and tunica media
b. Tunica interna, tunica externa and tunica media
c. Tunica interna, tunica media and tunica externa
d. Tunica media, tunica externa and tunica interna

Answer 1

Hint: The sequence of layers found in the walls of arteries are tunica interna, tunica media and the tunica externa. There are 3 layers found in the arteries and the veins based on the arrangement of their position. There are three layers forming the inner, middle and the outer structure of the wall.

Complete answer:
There are three types of layers found in the arteries. The outermost layer is called tunica externa. The smooth muscle is found in the middle layer known as the tunica media of arteries. A thin layer of elastic and white fibrous tissue covers an inner layer of endothelial cells, called tunica interna. It is the single layer of squamous epithelial cells called the endothelium, that covers the whole circulatory system.

> Tunica adventitia is the outermost layer of the heart. So, this cannot be the correct option for the sequence.

> Tunica interna, tunica externa and the tunica media are not the correct sequence from inside to outside. Tunica interna is the innermost layer so it lies internally, tunica externa is the outermost layer of the heart and the tunica media is the middle layer. So, the sequence will be interna – media and the externa. So, it will not be a correct statement.

> Tunica interna is the innermost layer made of endothelial cells and the tunica media is the middle layer and the tunica externa is the outermost layer. Hence, it is the correct statement and sequence of layers found in the arteries.

> Tunica media, tunica externa cannot be a right sequence. Thus, it will not be a correct sequence of layers found in the walls of arteries.

Hence, the correct answer is option (C).

Note: Layers or coatings of arteries consist of inner, middle and the outer layer. These 3 distinct layers form the walls of the arteries. Arteries are the largest of the vessels having abundance of elastic fibers on the walls.