Grade :-8(Science) Cell and tissue

                                Unit :- 17     Cell and tissues

Cell :-The structural and functional unit of life is called cell. Or

Basic unit of living being is called cell .

Tissues :-A group of cell which is similar in structure and function is called tissue .for example :Bone ,blood , muscle, etc are the animal tissues ,and  xylem and phloem etc. are the example of plant tissues .They are two types :

 A)Animal tissues

B) Plant tissues  

A) Animal tissue :A group cell animal cells having the same origin ,structure and function is called animal tissue .

 Types of Animal Tissue :-They are 4 types

1.)Epithelial Tissue

The animal  tissue which   cover and inner lining of the body surface, organs ,duct, blood vessels is known as epithelial tissue.

 Characteristics of Epithelial Tissue

Following are the important characteristics of epithelial tissues:

1.     The of cell of these tissue are  a single-layered or multi-layered.

2.     The tissues have the power to regenerate.

3.     The cell are arranged on a basement membrane .

4.     The tissues form the covering of organs and inner lining of cavities .

Functions of epithelial tissues :They have following functions :

i)Protection     ii) Secretion      iii)Sensation     iv)Absorption    v) Excretion  vi)Diffusion    vii)Cleaning   

Types of epithelial tissues :On basis of structure and functions they are following types :

i)Pavement epithelial  or squamous epithelial

ii)Cubical epithelial tissue

iii)Columnar epithelial

iv)Glandular epithelial

i)Pavement epithelial :The epithelial tissue having plate like flat hexagonal cell arranged without inter cellular space is called pavement epithelial .

Location :They are found in outer layer lungs ,kidney, heart, blood vessel  etc.

Functions .The major functions of this tissues are covering ,protection ,filtration etc.

ii)Cubical epithelial :The epithelial tissue made of single layered cubical cells is called cubical epithelial .

Location :They are found in the duct ,inside kidney, thyroid gland excretory organs inner parts of uterus etc.

Functions :The major functions of these tissues are covering ,protection, and secretion etc.

iii)Columnar epithelial :The epithelial tissue of single layered longated column like is called columnar epithelial .

 Location :They are found in large duct of kidney, inner part of stomach, inner parts of respiratory and reproductive system .

Functions :The major functions of these tissues are secretion and absorption .

iv)Glandular epithelial :The tissue which is found in various glands of the body is called glandular epithelial .

Functions : The major functions of this tissues are secretion of hormones enzyme, mucus, saliva digestive juice etc.

2.)Muscular tissues : The tissues which form muscles of the body is called muscular tissue .It is responsible for the movement of the body .

3.)Connective tissue :The tissues which help to connect or bind one tissue to another tissues or support them to keep in proper place is called connective tissue .It is to bind help to bind ,support ,and pack together different organs the body .

4.)Nervous tissue :The tissue which contains densely packed nerve cell or neuron is called Nervous tissue .It help to receive massage impulses from different part of body  and conduct impulses to the brain and spinal cord .

B)Plant tissue :A group of plant cells having same  origin and similar and structure and function is called plant cell .

 On the basis of division the plants tissue are classified into two types :

1.)Meristematic  tissue

2.)Permanent tissue

 1.)Meristematic  tissue :The tissue which is made up of from meristematic cells is called meristematic tissue :

Characteristics of meristematic tissue :

i)It has capacity of cell division .

ii)It has thin wall .

iii)Cytoplasm is dense .

iv)Intercellular space is absent .

 Types of meristematic tissue :On the basis of occurrence and position in the plant ,meristematic tissues are divided into 3 types :

1)Apical meristem: The meristematic tissues which are at the tip of stem ,root and their branch is called apical meristem .It help to increase the length root and stem .

2.)Lateral meristem :The meristematic tissue which occurs on the side of root and shoot is called  lateral meristem .It help to increase the thickness of root and shoot .

3.)Intercalary meristem :The meristematic tissue which are present at he base of leaf ,base of inner node, or at the base of leaf is called intercalary meristem .It help for elongation of organs .

2.)Permanent of tissue :A group of cell that do not  have power of cell division but have permanent shape for special function is called permanent tissue .The major function of permanent tissue are to conduct food, and water to different parts of plants ,to provide mechanical support and secrete substance i.e. oil, resin, latex etc.

Differences between plant cell and animal cell

Plant tissue	Animal tissue
i.)Cells of plant tissue have cell wall.	Cells of animal tissue do not have cell wall.
ii.)Some tissues are living and some are dead.	ii.9All tissues are living.
iii.)They are mainly of two types permanent tissue and meristematic tissue.	iii.)They are of four types muscle tissue, epithelial tissue, nervous tissue and connective tissue.
iv.)They provide strength and support to the plant.	iv)They control all functions.

The relation between cell tissue ,organ and system

Cell :-The structural and functional unit of life is called cell. Or

Basic unit of living being is called cell .

Tissues :-A group of cell which is similar in structure and function is called tissue .for example :Bone ,blood , muscle, etc are the animal tissues ,and  xylem and phloem etc. are the example of plant tissues.

Organ :The group of tissues  that perform a particular function is called organs .For example :Eye, Ear ,heart, lungs etc.

System :The group of organs that perform a particular function is called system .For example :Digestive system, circulatory system ,glandular system .

There are close relationship between cell , tissue ,organ ,and system because cell help to form tissue and tissue help to form organ and organ help to form system and system provide the life to cell ,tissue organ .

             Some major system ,organ, tissue and their functions

S.N.	Systems	Organs	Tissues	Functions
1    2.   3     4.    5.   6  7.     8.    9. .	Digestive system    Respiratory system   Circulatory system    Excretory system    Nervous system    Muscular tissue  Skeleton system     Reproductive system    Endocrine system	Mouth, stomach, liver ,intestine ,pancreas Lungs ,trachea    Heart, artery, vein  Liver ,kidney, skin   Brain, spinal cord, neuron  Muscles  Bone joints     Testes and ovary     Endocrine glands	Columnar epithelial,  Pavement, cubical epithelial Blood, epithelial  Pavement, cubical epithelial Nerve tissues  Muscular tissues Skeleton tissue   Cubical ,columnar epithelial Glandular epithelial	Digestion, and absorption of food .  Exchange of oxygen and   Carbon dioxide Transportation of oxygen and food nutrients Excretion of waste product.   Communication and co-ordination Movement of the body To give shape or framework the body For reproduction   Secretion  of hormone .