Question

5. What is the function of epithelial tissue and list the types with their role?

Answer 1

Epithelial tissue

• It is protective tissue of animal body.
• It covers most organs and cavities within the body.
• Cell of epithelial tissue are tightly packed and form a continuous sheet.
• They leave only a small amount of cementing material between intercellular space.

It is of various types:—

1. Squamous epithelium

• the cells of this tissue are arranged as tiles on floor.
• It is also of two types—

(i) simple squamous epithelium -

• Cell of this tissue are extremely thin & flat and form a delicate lining.
• It is present in blood vessels, alveoli of lungs, etc.
• It helps in exchange of substance like nutrients, gases, etc.

(ii) stratified squamous epithelium -

• The cells of this epithelium are arranged in many layers to prevent wear & tear.
• It is found in inner lining of mouth, respiratory system, fallopian tube, etc.

2. Cuboidal epithelium

• The cells of this tissue are cube shaped.
• It is found in lining of kidney tubules and ducts of salivary glands.
• It is responsible for mechanical support, secretion, excretion and absorption.

3. Columnar epithelium

• The cells of this tissue are tall or pillar like.
• It is present in respiratory tract, fallopian tube, etc.
• It is responsible for the absorption and secretion on inner lining of intestine.
• It also help in absorption and excretion.

4. Ciliated epithelium

• If hair like projection, cilia, are present on the free surface of columnar epithelium, it is called ciliated epithelium.
• These cilia can move and their movement pushes the mucus forward.
• It is also found in nosal passage, trachea, reproductive track/pipe ( both in male & female), etc.

5. Glandular epithelium

• If epithelium tissue act as gland, then it is called glandular epithelium.
• It is found in gastric gland, intestinal gland, pituitary gland,etc.
• It secrete organic chemical substances