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

Horse diseases-horse-pox, Horse-pox Horse pox is a benign disease chara...

Horse-pox Horse pox is a benign disease characterized by the typical pox lesions on the lower limbs or around the muzzle and buccal mucosa. This is a rare disease, caused by a

Introduction to fertilization, INTRODUCTIO N - Fertilization is a c...

INTRODUCTIO N - Fertilization is a complex process which involves fusion of male & female gametes. The male gamete in animals is called as sperm & the female gamete as o

Ecology, what is ecology?sub divison of ecology?

what is ecology?sub divison of ecology?

Explain spoilage of cereals and cereal products, Q. Explain Spoilage of Cer...

Q. Explain Spoilage of Cereals and Cereal Products? Cereals are the main source of energy to human beings. There are several varieties of cereals, of which wheat and rice are t

Regulation of the renal function, Q. Which are the three hormones that part...

Q. Which are the three hormones that participate in the regulation of the renal function? Antidiuretic hormone or ADH or vasopressin, atrial natriuretic factor (or ANF) and ald

Define biocompatible material, Define each term and give an example of an a...

Define each term and give an example of an application that uses the following: a. Biocompatible material b. Biodegradable material c. Biomimetic

Pathophysiology of cardiac tamponade, Q. Pathophysiology of Cardiac tampona...

Q. Pathophysiology of Cardiac tamponade? Progressive increase in pericardial fluid results in progressive increase in intrapericardial pressure, till a critical volume is reach

Control of pollution, Control of Pollution We have seen that pollution...

Control of Pollution We have seen that pollution affects human health, 'vegetation, crop yield, trees, fisheries, forests, buildings, archaeological monuments, tourism. These

Water loss - plant water relation, Water Loss - Plant Water Relation ...

Water Loss - Plant Water Relation Plants lose about 98% of water to the atmosphere by transpiration. Often water loss by transpiration exceeds gain by absorption and results

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