Chapter 4
Question 32-Name,classify,and describe the types of epithelia,also indicate their chief functions and location

1) Simple epithelia-Mostly abosrbs, secrets, and filtration, they are single cell layers.
a)Simple squamous epithelium, are laterally flattened, found in the kidneys and lungs, they are in the filter part of the membrane. Also for the lungs, they forms the wall of air sacs. b)Simple cuboidal epithelium-They have a single cell layer, and looks like a string of beads. They are found in the small ducts of glands of many kidney tubules. c) Simple columnar epithelium-Single layer, closely packed cells. It can be found in the digestive tract to the stomach all the way to the rectum. They are responsible for absorption and secretion. d) Pseudostratified columnar epithelium. They vary in height and responsible for secretion or absorbing sustances. They can be located in the respiratory tract.
2)Stratified epithelia-contain two or more cell layers, and their major role is protection.
a)Stratified squamous epithelium-the most common stratified epithelia, and a very thickly layered cell grouping. Mostly made for protection, these cells are subject to a lot of wear and tear. They can be found on every external part of the skin, and into every opening the body has. The epidermis, or top layer of skin, has keratin which is a hard and protective protein. b)Stratified cuboidal and columnar epithelia. The cuboidal epithelium is very rare, and found mostly in the larger glands such as sweat glands or mammary glands. The columnar epithelium is also rare. Small pieces of it are in the pharynx, male urethra, and lining of some glandular dutcs. It happens at transition areas or junctions between 2 other types of epilthelia. c) Transitional epithelium- it can be found in the hollow urinary organs. These cells are able to expand and contract to fit urine.