Compound or multilayered epithelia, Biology

Assignment Help:

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.

Related Discussions:- Compound or multilayered epithelia

Explain alterations occurring in milk and milk products, Alterations occurr...

Alterations occurring in milk and milk products In the dairy industry, milk is commonly given heat treatment for a wide variety of purposes. Depending on the heating temperatur

Explain diffusion and osmosis in cell structure, Explain Diffusion and Osmo...

Explain Diffusion and Osmosis in cell structure? Diffusion and Osmosis :  Diffusion through a cell membrane occurs as it does elsewhere, from an area of high concentration of

Dietary recommendations during diarrhoea, Q. Dietary Recommendations during...

Q. Dietary Recommendations during Diarrhoea? The diet should take into account the normal RDI and various adjustments made to the quantity and quality of the foods to be given.

Darwins theory of natural selection, Darwins theory of natural selection is...

Darwins theory of natural selection is considered a paradigm shift--a theory that has wide-ranging effects. Describe some of the advantages that this theory offered scientists once

Describe prematurity in coronaw artery disease, Describe Prematurity in cor...

Describe Prematurity in coronaw artery disease ? CAD in Indians tends to be more aggressive and manifests at a younger age. Generally CAD occurring before the age of 55 years i

Explain subphylum vertebrata, Subphylum  Vertebrata : (41,700 species, th...

Subphylum  Vertebrata : (41,700 species, the vertebrates) Vertebral column of bone or cartilage, head is well developed, heart is ventrally situated dorsal aorta, two pairs of

10 mcq question of plants, 10 mcq question in the topic of plants of 9th st...

10 mcq question in the topic of plants of 9th standard

Explain the width of the periimplant keratinized mucosa, Width of the Perii...

Width of the Periimplant keratinized Mucosa Clinical and experimental studies have failed to support the concept of an "adequate width" of keratinized tissue adjacent to natura

Genetic resources of biodiversity, Q. Genetic resources of biodiversity? ...

Q. Genetic resources of biodiversity? Genetic diversity or the gene pools are important for promoting and ensuring high agricultural yield. Genetic diversity provides crops wit

What is natural selection, What is natural selection? Natural selection...

What is natural selection? Natural selection is the method by which organisms that have certain favorable traits are better capable to survive and make successfully than organi

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd