Question

The endothelium of the blood vessel is composed of
A. Cuboidal epithelium
B. Squamous epithelium
C. Columnar epithelium
D. Ciliated epithelium

Answer 1

Hint: Endothelium of blood vessels is made up of flat epithelial cells. Based on shapes, epithelial cells have three kinds- squamous, columnar, and cuboidal.

Complete answer:Endothelium is a thin layer of flat cells that forms the interior lining of the blood vessels and lymphatic vessels. Endothelium originates from the mesoderm.
Now, what is epithelium? Epithelium or epithelial tissues are those which sometimes line the outer surfaces as well as the inner surfaces of organs and blood vessels and cavities of many internal organs throughout the body.
Epithelial cells have three kinds of shapes: squamous, columnar, and cuboidal.
Squamous epithelium is composed of cells that are flat i.e. wider than their height.
It can be found in the lining of the mouth, esophagus, blood vessels, and alveoli of the lungs.

Additional information: Simple squamous epithelia are tissues made of one layer of squamous cells that line surfaces.
Squamous cells are large, thin, and flat and consist of a rounded nucleus.
Like other epithelial cells, they have polarity and have a distinct apical surface with specialized membrane proteins.

So, the correct answer is B. Squamous epithelium.

Note: Generally, the classification of epithelial tissues is done according to the number of their layers or by the shape & function of the cells.