COLUMNAR EPITHELIUM

Between the endometrial and the cervical squamous epithelium, there is a single layer of mucus-producing, tall epithelium. With stromal papillae and clefts, columnar epithelium appears irregular. 

Columnar epithelium takes on a grapelike or “sea anemone” look when exposed to acetic vinegar and magnified. It turns a light shade of acetowhite. In the reproductive age group, columnar epithelium is located in the endocervix, encircling the cervical os, and is generally evident on the ectocervix.

 STRUCTURE:

Ciliated and non-ciliated simple columnar epithelium are the two types of simple columnar epithelium (glandular). The simple columnar epithelium’s ciliated section has microscopic hairs that aid in the movement of mucus and other substances along the respiratory system.

The simple columnar epithelium cells have a tall and thin form, like a column. The tissue’s apical surfaces face the organ lumens, whereas the basal side shows the foundation membrane. The nuclei are closer together on the cell’s basal surface.

The striated border on the apical side of absorptive columnar epithelium is made up of non-motile microvilli, providing for an increase in surface area for absorption. Ciliated columnar epithelium is the name for this type of epithelium.

Glandular Goblet cells produce mucins to create mucin in the Simple Columnar Epithelium. The majority of the cell is cytoplasm, containing membrane-bound secretory granules that secrete mucin and are located towards the cell’s apical surface.

CILIATED COLUMNAR EPITHELIUM:

Mucus and other chemicals are moved by mucociliary clearance in the respiratory system by ciliated columnar epithelium, which possesses numerous cilia.

It’s found in the fallopian tube lining, where cilia-generated currents drive the egg cell forward towards the uterus.

The neuroepithelium of the ependyma, which lines the ventricles of the brain and the central canal of the spinal cord, is made up of ciliated columnar epithelium. The cerebro-spinal fluid is moved by these cilia (CSF).

Excluding the lower pharynx and vocal folds, the respiratory system is lined with ciliated columnar epithelium that is pseudostratified as far as the bigger bronchioles. It also lines the tympanic cavity & auditory tube, as well as the uterine tube as well as the testis’ efferent ductules.

Mucus is secreted on the luminal surface of most of the respiratory tract by submucosal mucous glands & mucosa goblet cells, and cilia brush a layer of mucus, trapped dust particles, and other debris from the lung to the pharynx with in mucociliary rejection current, that clears the respiratory paths of inhaled particles. The path of oocytes and fertilized ova to the uterus is aided by cilia in the uterine tube.

Some columnar cells possess for secretion, and glandular tissue is a collection of such cells. Mucin-secreting and principal cells of the gastric epithelium often have mucus- and protein-filled (zymogen) vesicles in their apical domains. 

Goblet cells are formed when mucous cells are found among non-secretory cells, such as in the intestinal epithelium, and their apical cytoplasm and secretory contents expand to form a distinct cell shape.

NON-CILIATED COLUMNAR EPITHELIUM:

The single layer of non-ciliated column-like cells with oval nuclei near the base of cells makes up the non-ciliated simple columnar epithelium. Columnar epithelial cells with microvilli on the apical surface and goblet cells make up the cell layer.

These are brush edged and located in the lining parts of the gastrointestinal tract (inner lining of the esophagus, stomach, etc.).

The digestive system and urine bladder have non-ciliated simple columnar epithelium. The Simple columnar epithelial tissue is another name for it.

FUNCTION OF COLUMNAR EPITHELIUM:

• A single layer of epithelial cells makes up a simple epithelium, which is an epithelial tissue. The basement membrane is in intimate touch with these cells. A simple columnar epithelium is made up of columnar epithelial cells and is a simple epithelium. 
• Columnar epithelial cells are distinguished by their greater height than width. Secretion, excretion, & absorption are the primary functions of the simple columnar epithelium. 
• Ciliated cells are found in bronchi, uterine tubes, uterus, and a portion of the spinal cord. Through beating of their cilia, these epithelia can move mucus or other substances.
• These lengthy cells have been designed specifically for secretion & absorption. The existence of microvilli on the epithelium’s apical surface increases surface area. 
• These cytoplasmic extensions in the small intestine carry membrane-bound enzymes that finish the final stretch of digestion. Because of their placement on the membrane, close to transmembrane transport proteins, the end products of digestion can be absorbed fast.
• This epithelium also is designed to create a barrier to non-specific luminal substance transport. The cells of this epithelium are held together by junctional complexes that limit the movement of chemicals and ions through intercellular gaps. This is especially true in the digestive system, which has a high surface area that interacts with the outside world.
• This epithelium’s ciliated cells are intended to convey particles in a specified direction via wave-like motions.

STRATIFIED COLUMNAR EPITHELIUM:

The stratified columnar epithelium is made up of numerous layers of cells, with columnar cells at the apex and cuboidal or columnar cells in the deeper levels. The cells in the deeper layers of this stratified epithelium, like those in another stratified epithelium, may be distinct from those in the top layer. 

The epithelial tissue’s location and function determine how the cells on the apical surface are modified. This epithelium is uncommon and only occurs in a few locations throughout the body.

ILLUSTRATIONS OF STRATIFIED EPITHELIUM AND ITS EXAMPLES:

• The stratified columnar epithelium lines a tiny section of mucosal membrane of the anus as well as some parts of the male urethra in the excretory system.
• It’s located in the vast excretory duct of glands such as the esophageal glands in the endocrine system.
• In addition, some regions of conjunctiva of the eyes are lined by stratified columnar epithelium.

CONCLUSION:

A single layer of epithelial cells makes up a simple epithelium, which is an epithelial tissue. The basement membrane is in intimate touch with these cells. The morphology of the cells that make up this tissue can be used to classify it histologically. It might be squamous (like a scale), cuboidal (like a cube), or columnar (column-like). Secretion, excretion, & absorption are the primary functions of the simple columnar epithelium. Ciliated cells are found in bronchi, uterine tubes, uterus, and a portion of the spinal cord. Through the beating of their cilia, these epithelia can move mucus or other substances. The cilia also assist in the generation of currents in the uterine tube lumen, which helps move the egg cell forward towards the uterus.

The digestive system and urine bladder have non-ciliated simple columnar epithelium.