Essay On Epithelial Tissue

Tissues are groups of similar cells which have a similar structure and function. All of these cells work together to complete various tasks. There are four different types of tissue in the human body; connective, epithelium, muscle and nervous.

The epithelium tissue helps protect the body. It lines the surface. Epithelial tissue has an apical surface which means it is lined with microvilli above tight junctions. There are four main types of epithelium tissues; squamous epithelial cells, Cuboidal epithelial cells, columnar epithelial cells and ciliated columnar cells. The squamous epithelium protects the linings in the body such as blood vessels and air sacs in the lungs. The cuboidal epithelium protects things such as the kidneys and glands as they can

secrete and absorb substances. Columnar epithelium can also secrete which protects the body from being damaged. There is also ciliated epithelium which covers surfaces with cilia to protect the body from harm.

The cilia found in epithelial cells means that substances can pass easier and quicker. Squamous epithelial tissue is very thin and also very flat. It is usually one cell thick and is therefore in contact with the basement membrane. Because it is so thin, it is brilliant at diffusion and filtration, and it is also found in locations where these functions are essential. Squamous epithelial cells also have an egg-shaped nucleus. Columnar epithelial tissues are elongated and column-shaped. They occur in one or more layers. This type of epithelial tissue enables movement of molecules due to the simple thin structure and therefore allows easy exchange. The nucleus is also elongated and are normally located near the base of the cells. Columnar epithelium makes up the lining of the stomach and also the lining of the intestines. Some of which are specialised for sensory reception, for example the nose, ears and taste buds. Unicellular glands are found between the columnar epithelium and the duodenum. They secrete mucus, lubricating the surface of cells. Cuboidal epithelium tissues are a cuboidal shape, and each have a circular nucleus in the middle of them. This type of epithelium tissue is found in the

glands and in the lining of kidney tubules as well as in the glands ducts. Its main function is to absorb and secrete. They actively pump molecules in and out of the lumen, in which some of them are lined with microvilli, especially the kidney tubules.
The function of the nervous tissue is to send signals from one part of the body to