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epithelium

Skin Anatomy And Physiology

What Is The Epithelium?

The epithelium is one of the four types of basic tissue in your body. The others are nervous tissue, muscular tissue and connective tissue. Epithelial tissue is basically sheets of cells. These sheets make up your glands, cover your body, and line every body cavity.

Depending on how many layers of cells the epithelium has, the epithelium may be simple or stratified.

Simple Epithelium

These are made of one layer of cells. They are responsible for absorbing, secreting, and filtering material.

Stratified Epithelium

These are made of more than one layer of cells. These are usually found where rubbing occurs, which is where you would need more protection.

Cell Shapes

There are 3 main shapes of epithelial cells. These are:

  1. Squamous cells - these cells look like scales and are flat.
  2. Cuboidal cells - these cells look like boxes.
  3. Columnar cells - these cells look like columns, and are tall.

Types Of Epithelium

Epithelia are recognized according to the amount of layers and shape of cells in the top layers. Based on this, there are eight main types of epithelium.

These are:-

Simple Squamous Epithelium

These are close together and are flattened sideways. These occur where substances are filtered such as your kidneys and lungs. They look like a fried egg.

Simple Cuboidal Epithelium

These are made of one layer of cells of the same width and height, like a cube. These occur where substances are secreted and absorbed such as tubules of your kidneys (tubes in the kidney which reabsorb water).

Simple Columnar Epithelium

This is one tall layer of cells which are packed closely together. They cover your digestive system from your stomach to your rectum. They absorb and secrete material.

Pseudostratified Columnar Epithelium

These cell have different heights. They are called pseudo-stratified because the differing heights of the cells make you think that there are many layers of cells. However, there is only one layer of cells. These cells cover your respiratory tract.

Stratified Squamous Epithelium

These are made of many layers. Its top layer of cells are squamous, while the inner layer of cells are cuboidal or columnar. These cells protect you and form the outer layer of your skin.

Stratified Cuboidal Epithelium

These are not common in the body. They are usually made of two layers of cuboidal cells. They are typically found in your sweat glands and mammary glands.

Stratified Columnar Epithelium

These are also not common in the body. They are found in areas such as your pharynx (the part of the throat behind your mouth).

Transitional Epithelium

These line your hollow urinary organs. Its bottom layer of cells are cuboidal or columnar. Its top layer of cells changes shape when the organ is stretched.

epithelium.txt · Last modified: 2018/02/08 15:01 (external edit)