Answer
The covering and lining epithelia are classified on the basis of the shape of the cells and the number of cell layers present. The three common shapes are squamous, cuboidal, and columnar. The classes in terms of cell number are: simple (single layer) or stratified (multiple layers). In some cases, such as with endothelium, it is important to indicate their special location in the body. Merocrine glands (sweat glands) secrete their products by exocytosis; holocrine glands (oil glands) release their products by lysis of the entire cell; apocrine release their products by pinching off parts of the cell contents.
Work Step by Step
The covering and lining epithelia are classified on the basis of the shape of the cells and the number of cell layers present. The three common shapes are squamous, cuboidal, and columnar. The classes in terms of cell number are: simple (single layer) or stratified (multiple layers). In some cases, such as with endothelium, it is important to indicate their special location in the body. Merocrine glands (sweat glands) secrete their products by exocytosis; holocrine glands (oil glands) release their products by lysis of the entire cell; apocrine release their products by pinching off parts of the cell contents.
