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

Characteristic of ecotone, Characteristic of Ecotone A general charact...

Characteristic of Ecotone A general characteristic of ecotone is that it has sufficiently greater number of species and the diversity of most of the species at times is higher

Isolation of dna fragments, Isolation of dna fragments bound strongly with ...

Isolation of dna fragments bound strongly with protein 1.     Through pcr Pcr permits isolation of dna fragments from genomic dna through selective amplification of a spe

What is hazard identification, What is Hazard Identification Hazard  I...

What is Hazard Identification Hazard  Identification :  The  identification  of  known  or potential  health effects associated with  a  certain  agent.

Define methods of food preservation, Define methods of Food Preservation? ...

Define methods of Food Preservation? Food preservation is one of the oldest technologies used by human beings. The perishable food materials like fruits, vegetables, milk, meat

Structure of the sperm, Structure of the Sperm The spermatozoa in dif...

Structure of the Sperm The spermatozoa in different animal groups display a wide variety of shapes and sizes but all share a. basic morphological plan. The sperm in most anim

Rinderpest, R in d e rp es t It is also known as cattle plague re...

R in d e rp es t It is also known as cattle plague resulting in high fever, diarrhoea and high mortality rates. In year 2006, OIE has declared that India is free from rin

Define about the food production, Define about the Food Production? We ...

Define about the Food Production? We know that agriculture comprises the major source of food production. This is very true in a country like ours where the majority of the pop

Explain mixture in basic chemistry, Explain mixture in basic chemistry? ...

Explain mixture in basic chemistry? Mixtures :  Mixtures are produced by combining two or more substances. In contrast to the substances in compounds, the substances that com

Fibroblast, Fibroblast  is the term applied to a cell of connective tissue ...

Fibroblast  is the term applied to a cell of connective tissue which is separated from similar cells by some degree of the matrix material; fibroblasts secrete elastin and collagen

International codes used for system of binomial nomenclature, Q. Internatio...

Q. International Codes used for system of binomial nomenclature? In 1753 Linnaeus suggested a system of binomial nomenclature where each individual is denoted by two epithets,

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