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

Adaptations to high wind velocity, Adaptations to high wind velocity Th...

Adaptations to high wind velocity The mechanical force of the wind and the grinding action of sand, dust, snow and other materials driven by it cause the plants to adapt themse

Explain root pressure, Explain root pressure? How can you demonstrate it ex...

Explain root pressure? How can you demonstrate it experimentally? What is the cytological basis of Down's syndrome? Give two physical symptoms of this disorder. Describe why the

Natural vegetative propagation, in natural vegetative propagation which st...

in natural vegetative propagation which structure gives rise to new individuals?

Peptide bond formation, Peptide bond formation is catalyzed by peptidyl tra...

Peptide bond formation is catalyzed by peptidyl transferase.  The carboxyl  end of the amino acid bound to the tRNA in this reaction and in the P site is uncoupled  from the tRNA a

What is passive transport , The passive transport of molecules across a me...

The passive transport of molecules across a membrane does not require an input of metabolic energy. Rate of the diffusion or transport is proportional to the concentration gradient

Rejection reaction, Rejection Reaction For rejection reaction the phys...

Rejection Reaction For rejection reaction the physiological and biochemical processes are set in the pistil by the recognition reaction specific to the type of pollen that lan

#classification of parasitic protozoa.., most recent classification of para...

most recent classification of parasitic protozoa with its general characters

Show characteristics of protozoans, Q. What are the characteristics of prot...

Q. What are the characteristics of protozoans that make them resemble animals? Protozoans are unicellular beings with some related characteristics to animal cells. In compar

Explain protein, What is protein? 1) Protein is a source of backup ener...

What is protein? 1) Protein is a source of backup energy that your body keeps, a large difficult molecule made up of one or more chains of amino acids. Proteins perform a wide

What are the organic chemical groups, Q. What are the organic chemical grou...

Q. What are the organic chemical groups that describe carbohydrates? How are carbohydrates classified according to the presence of those groups? Carbohydrates are also known as

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