Question

Tunica intima is made up of:
a. Squamous epithelium
b. Smooth muscles
c. Elastic fibers and collagen fibers
d. Fibrous connective tissue

Answer 1

Hint: Arteries and veins consist of three layers which are named Tunica externa, middle Tunica media, and inner Tunica intima. Endothelial cells are present in tunica intima in the lining of the lumen of the vessel. The subendothelial layer in tunica intima is made up of loose connective tissue.

Complete answer:
The arteries carry blood away from the heart. The artery wall comprises three different layers such as tunica intima, tunica media, and tunica adventitia.

The tunica intima comprises a flattened smooth layer of endothelial cells, whereas tunica media is characterized by a concentric layer of vascular smooth cells and tunica adventitia is composed of fibroblasts, collagen, mast cells, and vasa vasorum.

The tunica intima is the innermost layer of the artery wall. It is made up of collagen, fibronectin, laminin, and other extracellular matrices. The tunica intima layer consists of endothelium, connective tissue, and internal elastic tissue. The tunica intima and the tunica media are separated through the internal elastic lamina.

The main function of the tunica intima is to provide support to the vessels. Also, it helps to change vessel diameter to regulate blood pressure and blood flow. The innermost layer of tunica intima consists of a layer of elastic fibers, a fine network of connective tissue, lining are bound together in a membrane pierced with many openings.

The tunica intima is made contact with the blood using the monolayer cells of the endothelium which has a contact surface with blood.

The structural and functional properties of the endothelium cells made it emerge as the main regulator of vascular hemostasis.

The endothelial cells may be altered in response to local and systematic stimuli.
Hence, Option (B) is the correct answer.

Note: There are three different layers of arteries. Tunica intima ( also called Tunica interna) which is the innermost layer simply made up of Squamous epithelium. Tunica media is the thickest middle layer made up of smooth muscles. Tunica adventitia is the outermost layer made up of collagen and elastic fibers.