epithelial tissue

Epithelial Tissue

Contextual Research Work – Group I

INTRODUCTIONAn Introduction to the Epithelial Tissue

EPITHELIAL TISSUE

TissuesPlant

Animal

Connective

Nervous

Muscle

Epithelium

The Epithelial Tissue

The Epithelial Tissue, also called the epithelium, is located in the lining and covering of many organs, as well as on the surface of the skin

Structure• The cells are closely

packed and are without intercellular spaces.

• The lowermost layer of the cells rest on a non-cellular basement composed of collagenous fibres.

Structure• The free surface of cells

may be modified into cilia and microvilli.

• Epithelial tissues could be simple i.e. made up of a single layer of cells or compound i.e. made of many layers of cells.

• Any epithelia can b ciliated if ‘cilia’ are present on its surface.

Location• Epithelial Tissues form a

continuous layer all over the external surface of the body.

• It lines the inside of all cavities such as those of stomach, intestine, throat etc.

• The skin, surface layers of mouth, alimentary canal and lungs are made of epithelial tissues

Functions1. Protection2. Exchange of Materials3. Absorption4. Elimination of Waste

Products5. Secretion6. Sensory

Features

Features of the Epithelial Tissue are explained through this graphic

TYPES OF EPITHELIALet’s study the types of epithelia in detail

TYPES

Epithelium

Simple

Squamous

Cuboidal

Columnar

Glandular

Unicellular

MulticellularCompoun

d Stratified

SIMPLE SQUAMOUSStructure Function Thin flattened cells

with a centrally-placed nucleus

Irregular-shaped cells

Cells are compactly arranged

Diffusion of materials or exchange of gases.

Protection from chemical & mechanical injury, entry of germs or from drying

Location Form lining of

mouth, oesophagus and lungs

Inner lining of blood vessels

Cover the skin surfaces

SIMPLE SQUAMOUS

SIMPLE CUBOIDALStructure Function Cube-like cells with

a central, spherical nucleus

Appear hexagonal in surface view

Secretion Excretion Absorption

Location Parts of nephron Lining of salivary,

pancreatic and sweat ducts

SIMPLE CUBOIDAL

SIMPLE COLUMNARLocation Lining of stomach,

intestine and gall bladder

Structure Tall, pillar or

column-like cells with nucleus at the base

Generally, have mucus cells in between

Function Secretion and/or

absorption Mucus lubricates

the passage

SIMPLE COLUMNAR

SIMPLE GRANDULARFunction Secrete enzymes,

mucus or hormones

Location Salivary, gastric,

intestinal and sweat glands

Adrenal and thyroid glands

Structure Cuboidal and

columnar epithelia are modified into glands

SIMPLE GRANDULAR

COMPOUND STRATIFIED

Location Skin Outer covering of

delicate organs

Function Prevent wear and

tear Protect organs

Structure Epithelial cells are

arranged one above another in many layers

COMPOUND STRATIFIED

Let’s ReviseWorksheet

Maximum Points: 8Maximum Time given: 5 minutes

ThankYou

Arish Mudra RakshasaChitransh Pandey

Disha DahiyaAnkita Kapoor

Suryansh TomarRishabh Jain