Simple cuboidal epithelium

Location in the body:
On the surface of the ovaries, the lining of nephrons, the walls of renal tubules, sections of the eye and thyroid, and salivary glands, simple cuboidal epithelium can be seen.
Function:
Simple cuboidal epithelium is made up of cells that are as tall as they are wide in a single layer. Secretion and absorption are two fundamental activities of the basic cuboidal epithelium. The small collecting ducts of the kidneys, pancreas, and salivary glands all have this epithelial type.

Simple Squamous Epithelium

Location in the body:
The lining of blood vessels such as arteries, veins, and capillaries contains simple squamous epithelium. It can also be found lining the alveoli, or air sacs, of a human’s lungs.
Function:
This epithelia lines the inner surface of all blood arteries (endothelium), the alveolar sacs in the lung, and the body cavities (mesothelium). The basic function of simple squamous epithelia is to let gases and tiny molecules to diffuse more easily.

Pseudostratified Epithelia

Location in the body:
Because ciliated pseudostratified columnar epithelia is primarily found in the larger respiratory airways of the nasal cavity, trachea, and bronchi, 
pseudostratified epithelium is also known as respiratory epithelium.
Function:
The respiratory tract’s pseudostratified columnar epithelium aids in protection. Mucus secretion traps these foreign particles, which are then excreted from the body via sneezing or coughing. Mucus also adds moisture to the air we breathe in through our nose.