Saturday, 2 January 2021

tissue 9th cbse lesson notes and video links

Tissues

Group of cells that are similar in structure and work together to achieve a particular function is called tissue

Differences between plants and animals for tissues

Plants
Plants are stationary
Don't move
Most of the tissues are supportive
Dead
As dead tissues give more strength and support
Growth is plants at some places continuos
And at some places limited

Animals
Move from place to place in search of food and shelter
They need more energy
So most of there tissues are living
To provide energy
Growth is uniform in animals
No demarcation in dividing and non division regions

Plant cells are classified as
Merisatmantic and permanent tissue

Meristmatic tissue
They are continuously dividing tissue
The cells of this tissue are active
Dense cytoplasm
Thin cellulosic walls
Prominent nucleus
Vacuoless absent
Vacuoles absent because
Meristematic cells divide frequently and give rise to new cells and hence they need dense cytoplasm and thin cell wall. 
Vacuoles causes hindrance in cell division as it is full of cell sap to provide turgidity and rigidity to the cell. ... 
Meristematic cells do not need to store these nutrients as they have compact shape.

Meristmatic tissue is of 3 types
Apical meristems
Internally meristem
Lateral meristem

Apical present in root and shoot tips
Helps in growth og shoot and root

Intercalary meristem
Present in  base of leaves or internodes
Lateral meristems help in increasing girth or circumference

Permanent tissue
Is of tow types
Simple(means they have same type of cells
And
Complex tissues(means they have different types if cell)
Qq
Simple tissues are of 3 types
Parenchyma
Collenchyma
Sclerenchym

Parenchyma

Its a basic packing tissue
They have thin walls
They are living
They are loosely packed
With large intercellular spaces
They give support and  stores food nutrients and water
Parenchyma having chlorophyll is chlorenchyma
Parenchyma having air spaces called arenchyma
(Diagram must learn from text book)


Collenchyma
They give flexibility
They are thickened at corners
They are living
They have little intercellular spaces
It helps in flexibility
Bending
Mechanical support
They are present in parts like
Leaf stalks below epidermis
(Diagram must learn from text book)

Sclerenchyma

It makes plant hard and stiff
Walls are thickened due to lignin
They are dead
They give strength to plant parts
They are present in
Stems
Around vascular bundles
Veins of leaves
Hard covering if seeds
Husk of coconut
(Learn diagram from text book)

Epidermis

Outermost layer of plants is epidermis
It may be single layered or multiple layered as in desert plants

Epidermal cells secrete waxy coating called cutin which is water resistant

This waxy coated epidermis gives
Protects
Against loss of water
Injury
Parasitic fungal invasion

They are continuously without intercellular spaces so that nothing enters inside

They are flat

They are thickened outer and side then inner walls

Epidermis have pores called stomata
Whose function is
Respirqtion
Tranpiration
Photosynthesis

In roots they have long hair like structures which help in increasing surface area of absorption of water and minerals

In desert plants they have very thick waxy coating to prevent loss of water

CORK

As the plants grow old

Outer epidermis is replaced by secondary meristem

Cells are cut off from this layer

This forms several layer of cork or thick bark
Compactly arranged

Cork cells are dead

There cells are thickened by suberin which is impervious to water and gases

COMPLEX TISSUE

complex tissue are xylem and phloem

Xylem and phloem are conducting tissues and called as vascular bundles

Xylem
Xylem consists of
Tracheids
Vessels
Xylem parenchyma
Xylem fibres

Cells have thick and dead

Tracheids and vessels are tubular helps in conduction of water

Parenchyma stores food and side ways conduction of water

Fibres helps in support

Xylem helps in transport of water and minerals

PHLOEM

phloem consists of
Serve tubes
Companion cells
Ploem parenchyma
Phloem fibres

Ploem is living tissue

Serve rubes are perforated

Unlike xylem they can conduct im both directions

Phloem helps in transportation of starch

Animal tissues

Epithelial tissue
Connective tissue
Muscular tissue
Nervous tissue

Epithelial tissue
The covering and protective tissue is epithelial
It covers most of cavities and organs of body
It also forms barrier to keep different organs separqte
They are tightly packed
Forms continuos sheet
They have small cementing between them
No intercellular spaces as tight
Anything entering inside or going outside should cross atleast one layer of epithelium
So its permeability is important
In exchange of various materials
All epithelium are separated from underlying tissue by underlying fibrous basement membrane
Different epitheli show different structures basing on their functions

Simple squamous epithelium

Eg
Lining of blood vessels
Lung alveoli
Oesophagis
Lining if mouth
Skin is also squamous
Where exchanges of substances takes place
They are simple
Flat
Thin
Delicate lining
So that exchange of substances occurs
And they are extremely permeable

Stratified squamous epithelium
At some places
Any layers are present
To avoid wear and tear
As they are in layers
Its called stratified
Example
In sole of feet

Columnar epithelium
When absorption and secretion occurs
Tall eoithelial cells are present
Theses are tall pillar like
Helps in movement across epithelial barrier
Example
Inner lining of intestine
Which liberates enzymes
And also a son's
Digested food
Ciliated epithelium
If counter cells have cilia
Hair like projections
Which help in movement of air
Cilia can move
Can push air or mucous forward
Example
Inner lining of respiratory tracts

Cubical epithelium
They are like cube cells
They give mechanical support
Example
Kidneys
Salivary glands

Glandular epithelium

Sometimes  portion of epithium fold inside
Multicellular gland is formed
They secrete substances at epithelial surface
Example
Lymph gland

Connective tissue

Blood
Bone
Cartilage
Ligament
Tendon
Areolar tissue
Adipose tissue

Blood
Blood is fluid connective tissue
Consist of plasma
And blood cells
Plassma has water ,protien and harmones
Blood cell are
rbc
Wbc
Platelets

Rbc helps in exchange of gases
Wbc gives immunity
Platelets helps in clotting.

Wbc types of cells
Acidophils  Bilobed nucleus
Basophills. Trilobed  nucleus
Neutrophils. Multilobed nucleus
Lymphocytes. Kidney shaped
Monocytes. Round nucleus

Functions of blood are
Exchange of gases
Immunity
Temperature regulation
Harmones travel
And so on

BONE
Bone is another example of framework that supports the body
It also anchors muscles and supports main organs
It is strong and non flexible
Bone cells are embedded in hard matrix
Which is composed of calcium and phosphorus
Cells present in bones are called osteocytes
Osteoclasts
Osteoblasts
Bone lining cells

206 bones are there

LIGAMENT
2 bones are connected by ligament
It is elastic
Has considerable strength
They have little matrix

TENDONS
bone are connected to muscle by tendon
They are fibrous
Great strength
Limites flexibility

CARTILAGE
Cartiqlge has widely spaced cells
Matrix composed of protiens and sugars
Cartilage is smooth
We. An bend cartilage but not bone
They are present
In ear lobes
Nose
Ear
Trachea
Nose
Cells of cartilage are called chondrocytes
Cartiqge don't have blood and nerve
3 types of cartilage are
Hyaline
Elastic
Fibro

AREOLAR TISSUE
Most abundant tissue
Present throughout the body
Found betwewnskin and muscles
Around blood vessels
Around nerves
In bone marrow
Funsctions are

Fills space inside organs
Supports internal organs
Repair tissues

ADIPOSE TISSUE
Fat storing adipose tissue
Found under skin
In between internal organs
Cellas are filled with fat globular
It also acts as
insulator
Store energy
Lrotects internal organs

Cells are called adipocytes
2 types of adipose tissue
White adipose store energy
Brown adipose themoregulation

Adipocytes or fat cells has lipid droplets
Of stored triglycerides
They swell as they store fat
They shrink
As they loose fat

Muscular tissue

Striated  or voluntary
Unstriated  or involuntary
Cardiac or involuntary

Striated or voluntary muscles

Mainly attached to bones and ligaments

Long cylindrical and blunt at ends

Branched

Multinucleate

Voluntary

Light and dark bands are present

Present in limbs  tongue

Unstriated muscles

It is present in those places which are in voluntary

Spindle shaped short

Uninucleate

Involuntary

Nolight and dark bands present

Cardiac
They are present in heart

They are short and braanched

Strition preset
Involuntary

Light and dark bands present

Intercalated disc's are found

Uninuvleate












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