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
is a wheat plant a eustele or a siphonostele or a protostele?

How is the cerebrum anatomically divided? The cerebrum is divided into two cerebral hemispheres, the right and the left. Each hemisphere is made of four cerebral lobes: frontal

Define r and K Strategists? Ecologists have identified two major types of reproductive strategies among species. Characteristic patterns can be seen among species relating the

Transposable elements are able to move around the genome by precise or imprecise excision events. What is meant by imprecise excision? A. Imprecise excision refers to a transpo

Signify the term in details - Pseudocoelom. A body cavity that isn't completely lined by mesoderm. Mesoderm is associated with only the ectodermal surface but not endoderm. The

Why there is difference in the colour obtained for the dextrin solution (ammonium sulphate and dextrin )when brought to iodine test Respetively by first half saturation test and t

Q. What is hypercholeslerolaemia? Cholesterol: It is a natural component of foods such as mutton, pork, ham, sausages, lamb, chicken, eggs (yellow), whole milk, cheese, ice-cre

Define Foam Spray Drying Method? This is an extension of spray drying and involves the use of gases dissolved under pressure prior to spraying. The main advantage is that the


Patients Not on HAART For HIV-infected patients requiring TB treatment who are not currently being treated with highly active antiretroviral therapy (HAART), it may be prudent