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
Q Concerning germ layers and the presence of coelom how are arthropods characterized? Arthropods are triploblastic and coelomate beings (they have three germ layers). Q. Co

Enumerate about the Baule unit  A mathematician from Gottingen by the name of B. Baule assisted Mitscherlich with his calculations.  The quantity of any growth factor (nutrient

digram or mammalian testis

Define classification of carbohydrates - Oligosaccharides? Oligosaccharides are short chains of saccharide units and are condensation products of three to ten monosaccharides.

What is the most excellent identification hypothesis for a plant tissue seen under the microscope having most cells undergoing cell division? The most excellent hypothesis is t

Anemochory - Dispersal of Seeds Seeds that are dispersed by air currents are usually light or are provided with special structures to help them remain air-borne for long peri

Role of Wound Epidermis and Apical Epidermal Cap Earlier described that amputation, the stump epidermal cells at the wound edge migrate over and quickly cover the wound to fro


Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Define method Used for Capsular Staining - Anthony Staining Method? Another method used for capsular staining is Anthony staining method, devised by E.E. Anthony in 1931. The m