These are called Epithelial Tissues.

Epithelial cells make up epithelial tissue. Depending on where they are in your body and what tasks they perform, the cells might be varied forms and grouped in a single layer or numerous layers.

You have many different kinds of epithelial tissue throughout your body. A few of them are:

Simple Squamous Epithelium – This form of epithelium lines blood arteries and bodily cavities and controls the entry of chemicals into the tissue beneath.

Pseudostratified Epithelium – The upper respiratory epithelium has a lot of cilia and lines the upper respiratory tract.

Transitional Epithelium – It is responsible for lining the majority of your urinary system and allowing your bladder to expand. When stretched, this is made up of many layers of cells that flatten out.