The kind of epithelium which forms inner walls of blood vessels is
(a) cuboidal epithelium
(b) columnar epithelium
(c) ciliated columnar epithelium
(d) squamous epithelium

Options

A. cuboidal epithelium
B. columnar epithelium
C. ciliated columnar epithelium
D. squamous epithelium

Answer

To determine the type of epithelium that forms the inner walls of blood vessels, we can analyze the options provided:

1. **Cuboidal Epithelium**: This type of epithelium consists of cube-shaped cells and is typically found in glands and their ducts, as well as in the kidney tubules. It is not the type of epithelium that lines blood vessels.

2. **Columnar Epithelium**: This epithelium is characterized by tall, column-like cells. It is commonly found in the digestive tract and respiratory tract, but it does not line blood vessels.

3. **Ciliated Columnar Epithelium**: This is a specialized form of columnar epithelium that has cilia on its surface. It is mainly found in the respiratory tract and helps in moving mucus. It does not line blood vessels.

4. **Squamous Epithelium**: This type of epithelium consists of flat, scale-like cells. It is known for its thinness, which allows for easy diffusion and filtration. Squamous epithelium is indeed the type that lines the inner walls of blood vessels, known as the endothelium.

Based on the analysis, the correct answer is:

**(d) squamous epithelium**