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

Determine the symptoms of shigellosis, Determine the Symptoms of Shigellosi...

Determine the Symptoms of Shigellosis Symptoms:  Pathogenicity involves the release of lipopolysaccharide endotoxin, which infects the intestinal mucosa. Shigellosis ranges fro

Explain about the waist to hip ratio (whr), Explain about the Waist to Hip ...

Explain about the Waist to Hip Ratio (WHR)? Two individuals who have the same BMI and the same total body fat may have different abdominal fat mass. Abdominal fat accumulation

What structural features do these organisms, What STRUCTURAL features do th...

What STRUCTURAL features do these three organisms have in common in terms of a) excretory systems b) respiratory systems c) circulatory systems and d) nervous systems ? The species

Explain community dietitians, Explain Community dietitians Community d...

Explain Community dietitians Community dietitians or  nutritionists  may  counsel  individuals and  groups on  sound nutrition practices  to  prevent  disease, maintain  healt

What is phylum hemichordata, What is Phylum Hemichordata ? The name "he...

What is Phylum Hemichordata ? The name "hemi"; (meaning "half") provides a clue to these animals, which have some of the features of chordates, and some features that are chara

Define st elevation in avr, Q. Define ST Elevation in aVR? Lead aVR oft...

Q. Define ST Elevation in aVR? Lead aVR often develops ST elevation as a reciprocal of ST depression in lead V2 to V6 or leads 2 and 3. It may occasionally show ST elevation in

Spermatophores, Spermatophores Many non-chordates do not release free ...

Spermatophores Many non-chordates do not release free sperms during copulation. They have a mechanism to bundle and enclose a number of sperms in a sheath usually made of gela

Are environmental phenotypical changes transmitted offspring, Are environme...

Are environmental phenotypical changes transmitted to the offspring? Changes caused on the phenotypes by the environment are not transmitted to the offspring unless their prima

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