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

Express difference between chromosomes and chromatin, What is the differenc...

What is the difference between chromosomes and chromatin?

Group selection, The effect of natural selection on colonies or population ...

The effect of natural selection on colonies or population favouring one group in preference to other may be referred to as group selection. A group can be the smallest collection o

TISSUES, difference between axon and cyton

difference between axon and cyton

Explain the functional properties of proteins, Functional properties of pro...

Functional properties of proteins These are those physico-chemical properties that enable the proteins to contribute to the desirable characteristics of the food Potential f

Define about the photometry - colorimetry, Define about the Photometry - co...

Define about the Photometry - colorimetry? Photometry is the measurement of the luminous intensity light or the amount of luminous light falling on a surface from such a source

What is gel, What is Gels Sol is free flowing liquid at room temperatur...

What is Gels Sol is free flowing liquid at room temperature, when it becomes relatively firm, it is called a gel. There are a number of factors that affect the strengths, elast

Assessment of development in children, Assessment of Development in Childre...

Assessment of Development in Children The development of a child is studied through various responses which he exhibits following a natural or experimental stimulus. Basical

Explain the term brown-sequard syndrome, Explain the term Brown-Sequard Syn...

Explain the term Brown-Sequard Syndrome Brown-Sequard syndrome is a rare spinal disorder that results from an injury to one side of the spinal cord in which the spinal cord is

Define metabolic response to food - requirement of energy, Define Metabolic...

Define Metabolic response to food - Requirement of Energy? Eating requires energy for the ingestion and digestion of food, and for the absorption, transport, inter conversion,

Name the animals having a single opening as mouth and anus, One example of ...

One example of animals having a single opening to the outside that serves both as mouth as well as anus is: 1. Octopus 2. Asterias 3. Ascidia 4. Fasciola Ascidia i

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