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

Which of groups is not ionizable, Which of the following groups is NOT ioni...

Which of the following groups is NOT ionizable? Select one: a. Guanidinium b. Imidazole c. Phosphoryl d. Amine e. Aldehyde

Pelagic zone - organisation of the marine ecosystem, Pelagic Zone - Organis...

Pelagic Zone - Organisation of the Marine Ecosystem The waters contained in the sea basin, constitute the pelagic zone which is divided into The neritic zone situ

#title.Physiology , What neurotransmitter is released from the preganglioni...

What neurotransmitter is released from the preganglionic parasympathetic neurons

Initial phase for nutritional treatment of neuro trauma, Define Initial Pha...

Define Initial Phase for nutritional treatment of neuro trauma patients? In this, the life threatening conditions need to be controlled first.  Soon the nutritional support mu

Define the rehabilitation phase of spinal trauma disease, Define the Rehabi...

Define the Rehabilitation Phase of spinal trauma disease? Once the patient s condition stabilizes, individualized diets need to be recommended, based on the energy and nutrient

Management goals for diverticular disease, Q. Management goals for divertic...

Q. Management goals for diverticular disease? The management goals discussed above are basic to prevention of diverticulitis. However, diet therapy during diverticulitis may b

Mechanism of urine formation, MECHANISM OF URINE FORMATION - Production...

MECHANISM OF URINE FORMATION - Production of urine is uripoisis or diuresis. First of all it was explained by Kushney. Nephron separates acidic urine from basic blood, so ma

What is burden of rheumatic heart diseases, What is Burden of Rheumatic Hea...

What is Burden of Rheumatic Heart Diseases? Although in the twenty-first century RHD has been eradicated in western countries, in India and other developing countries it contin

What do you mean by diabetes mellitus, Q. What do you mean by Diabetes Mell...

Q. What do you mean by Diabetes Mellitus? Diabetes Mellitus as you know is a metabolic disorder, which is characterized by high blood sugar. It is a chronic disease condition,

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