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 much nacl can be made using 30g of nacl, How much of a 10% w/v of nacl ...

How much of a 10% w/v of nacl can be made using 30g of nacl? Please show all steps.

Locomotor organelles, Locomotor Organelles The protozoan locomotor org...

Locomotor Organelles The protozoan locomotor organelle may be Flagella, Cilia or Pseudopodia. These are of considerable value in classification of protozo

What is the function of lymph nodes, Explain function of lymph nodes? L...

Explain function of lymph nodes? Lymph nodes have white blood cells which ingest bacteria and prevent them from reaching the circulation.

What is vacuoles, What is Vacuoles A very conspicuous feature in most p...

What is Vacuoles A very conspicuous feature in most plant cells is the presence of one or more large vesicles called vacuoles which are separated from the rest of the cytoplasm

What is etherification, What is Etherification The act or process of m...

What is Etherification The act or process of making ether; specifically, the process by which a large quantity of alcohol is transformed into ether by the agency of a small am

Explain the vitamin k dependent proteins, Explain the Vitamin K dependent p...

Explain the Vitamin K dependent proteins? The four vitamin K-dependent procoagulants (factor II or prothrombin, and factors VII, IX, and X), about which we studied above, are s

Oogenesis, Oogenesis Oogenesis is the formation of ovum from oogonial...

Oogenesis Oogenesis is the formation of ovum from oogonial cells that are formed in the ovary from primordial germ cells. And as in spermatogenesis it involves meiosis to pro

Which animals maintain constant body temperature?, Which of the below terms...

Which of the below terms is used to describe animals which maintain a constant body temperature by producing heat by metabolic oxidations (muscle contractions) and losing excess he

Explain diseases of pericardium, Q. Explain Diseases of pericardium? Pe...

Q. Explain Diseases of pericardium? Pericardium is the sac covering the heart. Pericardium consists of two layers-the visceral pericardium (epicardium) and the parietal pericar

What happens within the cell in the first interface period, What are the ev...

What are the events that mark the beginning and the end of the first interphase period? What happens within the cell in this period? The first interphase period is the G1. It s

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