Columnar Epithelium

There are different types of cells in the body. Of these, the epithelial cells are lined up against the surface of the skin and the linings of the internal organs of the human body systems such as glands. The epithelial cells are one of the four basic cell types of animal tissue. These cells are in turn classified according to the morphology of their cells. They are classified as simple, stratified and pseudostratified epithelial cells. The columnar epithelial cells are a type of simple epithelial cells.

Description

The columnar epithelial cells are oval in shape. Their height is about 4 times their width. They have a nucleus that is elongated and is located towards the base of the cell. These cells are found in the lining of the stomach and intestines. A few of these cells are present inside the reproductive organs, glands and places in the body where secretion and absorption takes place. The cells present in the respiratory tracts are found to have small hair-like structures called the cilia. Cells in intestines have microvilli that help in increasing the surface area for absorption. In between the cells in the intestine, there are tiny cells called goblet cells present. These cells are present in the respiratory passages as well. They secret mucus that serves as a protective layer and lubricant. There are three types of columnar epithelial cells.

Types

Simple Columnar Epithelium
The lining of stomach, small intestine and large intestine are made of this type of cell. You will also find it in the cervix and uterus. This type of cell is divided into two more types; the ciliated cells and the non-ciliated cells. The ciliated cells line the upper respiratory tract, Fallopian tubes, uterus and even the spinal cord. The function of the cells in this case is to help in the movement of the mucus and other substances along the organs. They also help in pushing the egg cell in the uterine tube into the uterus.

Stratified Columnar Epithelium
This consists of column-shaped cells. These rare type of cells are arranged in multiple layers. These cells are found in the ocular conjunctiva of the eye, pharynx, mammary gland, salivary gland, uterus, male urethra, vas deferens and the anus. The function of these cells include secretion of mucus and protection of the organs in which it is present.

Pseudostratified Columnar Epithelium
This lining has single-layered cells. These cells have the nuclei placement similar to the stratified epithelial cells. They are called pseudostratified as they give an impression as if there is more than one layer of these cells. The ciliated pseudostratified cells are present in the trachea and upper respiratory tract. The non-ciliated pseudostratified cells are found in the vas deferens, and the pseudostratified cell with stereocilia are present in the epididymis. The function of the pseudostratified cells is secretion as well as absorption.

The epithelial cells are found in many organs of the body and help in absorption of substances as well as secretion of mucus.