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A Handbook of Biology

ÅÑÏMÅL TÏSSÜËS

2

A group of cells having same origin, structure and function

are called the tissues. Animal tissues are of 4 types:

(i) Epithelial (ii) Connective (iii) Muscular (iv) Neural

1

In unicellular organisms, all functions like digestion,

respiration and reproduction are performed by a single cell.

In multicellular animals, a group of similar cells along with

intercellular substances perform a specific function. Such an

organisation is called tissue.

It has a free surface that faces body fluid or outside

environment.

Epithelial tissues are of 2 types: Simple and Compound.

Covers or lines body or body parts.

Compactly packed cells with little intercellular matrix.

ËPÏTHËLÏÅL TÏSSÜË (ËPÏTHËLÏÜM)

Pseudo-stratified

(columnar)

Ciliated columnar

Simple columnar

Simple squamous

Simple cuboidal

SIMPLE EPITHELIUM

It is composed of a single layer of cells. It lines body cavities, ducts and tubes.

Based on structural modification of cells, simple epithelium is 3 types: