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

How vaginal infections cause, How Vaginal infections cause Sulfonamide ...

How Vaginal infections cause Sulfonamide creams, other ''broad-spectrum'' vaginal preparations, and currently available preparations of Lactobacillus  species or dairy products

Is herbivorism a form of predatism, Q. Is herbivorism a form of predatism? ...

Q. Is herbivorism a form of predatism? The Herbivorism is a form of predatism in which first order consumers feed from producers (plants or algae). For instance, fruits and bir

Occurrence of earthquake, Among the different natural hazards, earthquakes ...

Among the different natural hazards, earthquakes happen to be the most feared and dangerous because of their sudden impact and the devastation they cause in a matter of few seconds

Does the environment exert an influence on the phenotype, Does the environm...

Does the environment exert an influence on the phenotype? A phenotype may be changed (compared to the original situation conditioned by its genotype) by nongenetic means. Examp

What is chromosomes, What is Chromosomes ? The terminology used to desc...

What is Chromosomes ? The terminology used to describe DNA replication may sometimes be confusing. Originally, the term "chromosome" referred to the structures seen through the

What are the factors to an actual shift in the demand curve, What are the f...

What are the factors to an actual shift in the demand curve? Factors that cause an actual shift within the demand curve are as follows: When prices rise or fall that would c

How bone implant interface can be evaluated, How bone implant interface can...

How bone implant interface can be evaluated 1) Evaluation of the bone - implant interface can be done by following: i) Implant mobility and discomfort a)  Clinical implan

What are some factors that can lead to protein denaturation, What are some ...

What are some factors that can lead to protein denaturation? Protein denaturation can be caused by temperature variation, pH change, alters in the concentration of surrounding

Does ploidy reduction occur in mitosis, During which meiosis division does ...

During which meiosis division does ploidy reduction occur? Does ploidy reduction occur in mitosis? In the cell division by meiosis ploidy reduction occurs in meiosis II. Initia

Define the v2 receptor antagonist, Define the V2 receptor antagonist A ...

Define the V2 receptor antagonist A new drug named ANTI-V2R has been developed that is a V2 receptor antagonist.  When ANTI-V2R binds to a V2 receptor, there is no binding of v

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