Simple or unilayered epithelia, Biology



  • It is composed of large flat cells whose edges fit closely together like the tiles in a floor, hence it is also called pavement epithelium.
  • The cells rest on a thin basement membrane.

e.g. This epithelium is present in the terminal bronchioles and alveoli of the lungs, wall of the Bowman' capsules and descending limbs of loops of henle of the nephrons of the kidneys, membranous labyrinth (internal ear), blood vessels, lympth vessels, heart, coelomic cavities, and rete testis of the testis.

  • In the blood vessels, lymph vessels and heart it is called endothelium.
  • In the coelom, it is called mesothelium.
  • The cells of endothelium and mesothelium may become wavy, hence these epithelia are called 'tessellated'.


  • The cells are cubical and more or less squarish in shape.
  • The nuclei are rounded and lie in the centre of the cells.
  • The cells of cuboidal epithelium often form microvilli on their free surface.
  • This given a brush-like appearance to their free border called brush bordered cuboidal epithelium.

1564_simple cuboidal epitheilium.png

eg. -  

  • Small salivary and pancreatic ducts, thyroid vesicles, parts of membranous labyrinth,
  • Proximal and distal convoluted tubules of the nephrons and the pigment cell alyer of the retina of the eye.


  • The cells are elongated and placed side by side like column.
  • Certain cells of this epithelium contain mucus (a slimy substance) and are called goblet (or mucous) cells as they look like globlet.

e.g. The intestinal mucosa (= mucous membrane) has microvilli to increase the absorptive surface area and is called brush-bordered columnar epithelium which is highly absorptive.

  • It lines the stomach, intestine, gall bladder and bile duct.
  • It also forms the gastric glands, intestinal glands and pancreatic lobules (present in the pancreas) where it has secretory role and is called glandular epithelium.

377_simple columnar epithelium.png 2216_simple columnar epithelium1.png


Simple Columnar Epithelium                                                      Simple Ciliated Epithelium


  • The cells bear numerous hair like outgrowths, the cilia, arising from basal granules. (i) Ciliated Columnar Epithelium -
  • It comprises columnar cells which have cilia on the free surface.


  • This epithelium lines most of the respiratory tract and fallopian tubes (oviducts).
  • It also lines the ventricles of the brain and the central canal of the spinal cord.
  • It is also present in tympanic cavity and auditory tube (Eustachian tube).

(ii) Ciliated Cuboidal Epithelium -

  • It consists of cubical cells which have cilia on the free surface. e.g. ® It occur in certain parts of nephorons of the kidneys.
  • In the respiratory tract the cilia help to push mucus towards the pharynx (throat).
  • In the oviducts the cilia help to move an egg towards the uterus.
  • The cilia of the ventricles (cavities) of the brain and central canal of the spinal cord help to maintain the circulation of cerebrospinal fluid present there.


  • Although epithelium is one cell thick yet it appears to be multi-layered which is due to the fact that the nuclei lie at different levels in different cells.
  • The cells are columnar, but unequal in size.
  • The long cells extend up to free surface.
  • The short cells do not reach the outer free surface.
  • The long cells have oval nuclei, however, short cels have rounded nuclei.
  • Mucus secreting goblet cells also occur in this epithelium.

1272_pseudo stratified.png

Posted Date: 10/1/2012 2:36:07 AM | Location : United States

Related Discussions:- Simple or unilayered epithelia, Assignment Help, Ask Question on Simple or unilayered epithelia, Get Answer, Expert's Help, Simple or unilayered epithelia Discussions

Write discussion on Simple or unilayered epithelia
Your posts are moderated
Related Questions
Pattern of Limb Development The first visible sign of limb development is the appearance of ridge or thickening on each lateral side of the embryo of amniotes. The ridge call

Determine the prevention of Cholera Prevention:  Following recommendations are  there to prevent cholera  outbreak: Drink only water that you have boiled or treated with

Describe the Technique of Operation in prosthetic valve endocarditis? The operative principle is drainage of abscess, removal of debris and valve rep or replacement to reverse

Types of Surgery :  Tricuspid valvotomy is done as an open procedure at the end of surgery on mitral and/or aortic valve. It can be done on an arrested heart or on a beating heart

Define Physiologic Functions of Iodine? Thyroid hormone performs multiple functions as regulator of cell activity and growth. The hormone has crucial metabolic roles in the foe

Q What is the kind of digestive system of echinoderms? Echinoderms present a complete digestive system with anus and mouth. Q. Do sea urchins have teeth? Sea urchins ha

Define Steps for prevention strategies of Obesity? The first and most important step for the rapidly progressing developing countries is to collect and organize data from vario

Explain the Most Probable Number (MPN)? MPN is a statistical estimating technique which is based on the fact that more the number of bacteria in a sample, more is the dilution

What are the infructescences, pseudofruits and parthenocarpic fruits? The Infructescences are aggregated fruits formed from inflorescences, aggregated flowers. Grape clusters a