Compound or multilayered epithelia, Biology

COMPOUND EPITHELIA (MULTILAYERED EPITHELIA) -

  • These are made up of more than one layer of cells.
  • The compound epithelia may be stratified and transitinal.

1.      STRATIFIED EPITHELIUM -

  • It has many layers of epithelial cells, however, the deepest layer is made up of columnar or cuboidal cells.
  • On the basis of the shape of the cells present in the surperficial layers.

It is of four types :-

(i) Stratified Squamous Epithelium -

  • The cells in the deepest (= basal) layer are columnar or cuboidal with oval nuclei.
  • It is called germinative layer (= stratum germinativum).
  • The cells of this layer divide by mitosis to form new cells.
  • The new cells gradually shift outward.
  • In the middle layers the cells become polyhedral with rounded nuclei.
  • These are called intermediate layers.
  • The superficial layers are flat with transversely elongated nuclei.
  • These layes are called squamous layers.
  • It is of two types : (a) Keratinized Stratified Squamous Epithelium.

(b) Nonkeratinized Stratified Squamous Epithelium.

(ii) Stratified Cuboidal Epithelium -

  • It has outer layer of cuboidal cells and basal layer of columnar cells.
  • It forms the epidermis of fishes and many urodels (tailed amphibians such as salamanders). e.g. ® It also lines the sweat gland ducts and larger salivary and pancreatic ducts.

(iii) Stratified Columnar Epithelium -

  • It has columnar cells in both superficial and basal layers.
  • e.g. It covers the epiglottis and lines mammary gland ducts and parts of urethra.

(iv) Stratified Ciliated Columnar Epithelium -

  • Its outer layer consists of ciliated columnar cells and basal layer of columnar cells. e.g. ® It lines the larynx and upper part of the soft palate.

2.      TRANSITIONAL EPITHELIUM (= UROTHELIUM) -

  • This epithelium consists of 4 to 6 layers of cells.
  • The cells of deepest (= basal) layer are columnar or cuboidal.
  • The cells of middle layer are polyhedral or pear shaped.
  • The cells of the surface layer are large and globular or umbrella shaped.
  • There is no germinative layer or basement membrane but shows mitosis.
  • e.g.  renal calyces, renal pelvis, ureters, urinary bladder and part of the urethra.
Posted Date: 10/1/2012 2:40:20 AM | Location : United States







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

Write discussion on Compound or multilayered epithelia
Your posts are moderated
Related Questions
Abortions Abortion in dairy cattle is commonly defined as a loss of the foetus between the age of 42 days and approximately 260 days (buffaloes 300 days). It is important to d

secondary growth in roots

LUNG S (PULMONES) - Present in pleural cavity. Covered by double layered pleura. Outer parietal pleura and inner visceral pleura. Both are continuous, slip on

Determine the types of Emulsions? A food emulsion is basically a two phase system consisting of a liquid, such as oil, wax or essential oil and water. An emulsion has 3 parts -

what is the biological significance of the skeleton and supporting system in animals

Classification of the river zones The course of a river can be classified in two ways Firstly by its physical characteristics and Secondly by the presence or absen

Agrostology : This is related to all types of grasses. Agrostology is sometimes called as graminology. Agrostology is the scientific study of grasses. It typically encompasses the

What would be the approximate number of amino acids of a protein with a mass of 203 kd? Assume an average molecular weight for amino acids of 110 grams/mol.

Hirschsprungs Disease (Congenital Megacolon): This  is also known as congenital megacolon. There is absence of ganglion cells, submucus plexus  and intramural plexus  (parasym

Determine some Methods of Blood Glucose Estimation? The various types of methods for estimation of blood glucose can be grouped under two groups: a) Chemical methods b) E