Tissues Class 9 CBSE Notes

Tissue chart
Tissue chart

PLANT TISSUE – Meristematic & Permanent

Meristematic Tissue 

These are simple living tissues having thin walled compactly arranged immature cells which are capable of division and formation of new cells.

Main features of Meristematic tissues are :

  • Thin primary cell wall (cellulosic).
  • Intercellular spaces are absent (compact tissue).
  • Generally vacuols are absent, dense cytoplasm & prominent nuclei are     present.
  • Large numbers of cell organelles are present.
  • Active metabolic state, stored food is absent.
  • Actively dividing cells are present in growing regions of plants e.g., root &   shoot tips.

Classification on the Basis of Origin

Primary (Promeristem)  
  • Derived directly from the meristems of embryo.
  • They consist of cells derived from primary meristem.
  • They add to primary growth of plants.
Secondary
  • Formed by permanent tissues.
  • These are having cells derived from primary permanent tissue.
  • They usually add to the diameter of plants.
Permanent tissue differentiation Secondary meristem

Classification on the Basis of Location

Apical Meristem

  • It is present at the growing tips of stems and roots.
  • Cell division in this tissue leads to the elongation of stem & root, thus   it is involved in primary growth of the plant.

Intercalary Meristem  

  • It is present behind the apex.
  • It is the part of apical meristem which is left behind during growth     period.
  • These are present at the base of leaf & internode region.
  • These lead to the increase in the length of leaf (Primary)
  • e.g., in grass stem, bamboo stem, mint stem etc.

Lateral Meristem

  • It is also called as secondary meristem.
  • It occurs along the sides of longitudinal axis of the plant.
  • It gives rise to the vascular tissues.
  • Causes growth in girth of stem & root.
  • They are responsible for secondary growth.

PERMANENT TISSUE

  • The permanent tissues are composed of those cells which have lost their capability to divide.
  • They have definite shape, size and thickness. The permanent tissue may be dead or living.
  • The division & differentiation of the cells of meristematic tissues give rise to permanent tissues.
  • In cell differentiation, developing tissue and organs change from simple to more complex forms to become specialized for specific functions.
  • The cells of permanent tissue loose the capacity to divide and attain a permanent shape, size and function.

Depending upon the Structure and Composition, the Permanent tissues are classified into two types :

Simple Permanent Tissues

  • These are made up of same type of cells which are similar structurally   and functionally.
  • They include two types of tissue :

Protective Tissues : These tissues are primarily protective in   function. They consist of :

Epidermis
  • Epidermis forms one cell thick outermost layer of various body   organs of plants such as leaves, flowers, stems and roots.
  • Epidermis is covered outside by cuticle. Cuticle is a water-proof layer of waxy substance called as cutin which is secreted   by the epidermal cells.
  • Cuticle is very thick in xerophytes.
  • Cells of epidermis of leaves are not continuous at some places   due to the presence of small pores called as stomata.
  • Each stomata is guarded by a pair of bean-shaped cells called   as guard cells. These are the only epidermal cells which possess   chloroplasts, the rest being colourless.
Protective tissue
Functions of Epidermis
  • The main function of epidermis is to protect the plant from   desiccation and infection.
  • Cuticle of epidermis cuts the rate of transpiration and evaporation of water and prevents wilting.
  • Stomata in epidermis allow gaseous exchange to occur during photosynthesis respiration.
  • Stomata also helps in transpiration.
Cork or Phollem 
  • In older roots and stems, tissues at the periphery become cork     cells or phellem cells.
  • Cork is made up to dead cells with thick walls and do not have   any intercellular spaces.
  • The cell walls in cork deposit waxy substance called as suberin.
  • The cells of cork become impermeable to water and gases due   to the deposition of suberin.
  • The cork cells are without any protoplasm but are filled with   resins or tannins.
corke
Functions of Cork
  • Cork is protective in function. Cork cells prevent desiccation,   infection and mechanical injury.
  • Imperviousness, lightness, toughness, compressibility and   elasticity make the cork commercially valuable.  • Cork is used for insulation, as shock absorber in linoleum.
  • Cork is used in the making of a variety of sport goods such as   cricket balls, table tennis, shuttle cocks, wooden paddles etc.

Supporting Tissues : These are supportive in function and are of three types

tupe of plant tissue

Parenchyma : It is the fundamental tissue.

  • Tissue first time evolved in bryophyte.
  • Thin walled cells, oval or spherical in structure.
  • Cell wall mainly composed of cellulose & pectin.
  • Large central vacuole for food & water storage.
  • Primary function is food storage.
Parenchyma
  • Some parenchyma involved in excretory substance storage are so called as idioblast, storing such as resin, tannin, gums &oils.
  • In typical parenchyma chlorophyll is absent.
  • Chloroplast containing parenchyma tissue are chlorenchyma which perform photosynthesis e.g., mesophyll of leaves.
  • In hydrophytic plants aerenchyma (a type of parenchyma containing air spaces) provides buoyancy.
  • Parenchyma provides turgidity to cells.

Collenchyma : It is the living mechanical tissue

Collenchyma
  • Elongated cells with thick corners.
  • Localized cellulose & pectin thickening.
  • Provides flexibility to plant parts & easy bending of various   parts of plant.
  • Present only in herbaceous dicot stem.
  • Present at thin margin of leaves.
  • Few chloroplasts may be present.
  • Gives mechanical strength & elasticity to the growing stems

Sclerenchyma : (Scleras–hard) Strengthening tissue

Sclerenchyma
  • Composed of extremely thick walled cells with little or no protoplasm.
  • Cells are dead & possess very thick lignified walls.
  • Lignin is water-proof material.
  • Intercellular spaces are absent.

Cells of sclerenchyma are of two types

Sclereids :
  • These are also called grit cells or stone cells.
  • These are small cells, where lumen is so small due to higher thickening of cell wall, as present in drup fruit (mango, coconut, walnut) in legume seeds (Macrosclereid).
Sclereids
Fibers
  • They are very long, narrow, thick, lignified cells. Lumen is large as   compared to sclereids. Generally 1-3 mm long.
  • In the thick walls of both the fibres and sclereids are present thin   areas called as pits.

Sclrenchyma Fibres

  • These are used in the manufacture of ropes, mats & certain textile     fibres.
  • Jute and coir are obtained from the thick bundle of fibres.
Sclrenchyma Fibres

Complex Permanent Tissues

  • It consists of more than one type of cells which work together as a     unit.
  • It helps in transportation of organic materials, water & minerals.
  • It is also known as conducting or vascular tissue.
  • Xylem & phloem together form vascular bundles.

Xylem

Also known as wood and is a vascular and mechanical tissue.    Thick walled cells are found in the form of tubular passages.

Xylem

Xylem consists of four types of cells called as elements

Tracheids

They are elongated angular dead cells (primitive elements) mainly   involved in conduction of water and minerals in gymnosperms.

Vessles

  • They are advance element (generally found in angiosperms).
  • Vessels are cylindrical tube like structures placed one above the other end to end which form a continuous channel for efficient conduction of water.

Xylem parenchyma

They are small & thick walled parenchymatous cells subjected for   storage of starch (food).

Xylem sclerenchyma

  • Thy are non-living fibres with thick walls and narrow cavities provide   mechanical support.
  • Except xylem parenchyma all other xylem elements are dead.
  • The annual rings present in the trunk of a tree are xylem rings.
  • By counting the number of annual rings, we can determine the age of   a tree.

Phloem

They also consist of both parenchymatous and schlerenc-hymatous cells.

Phloem

Phloem consists of four types of element :

Sieve tubes

  • Sieve tubes are slender tube like structures made up of elongated,   thin walled cells placed end to end. 
  • The end walls of sieve tube cells are perforated by numerous pores,   called as sieve plates.
  • Nucleus of sieve cell degenerates at maturity. However, cytoplasm  persists, because of protoplasmic continuation of sieve tube with  companion cell through plasmodesmata.
  • Sieve cells possess slime protein or protein which is concerned with  growth and repair of sieve cells

Companion cells

  • Companion cells have dense cytoplasm and prominent nuclei. 
  • Sieve cells & companion cells are so called sister cells because they   originate from single mother cell.

Phloem fibre

They give mechanical support to sieve tubes.

Phloem parenchyma

They store food and help in radial conduction of food.

Leptome

  • Main part of phloem involved in conduction of food, which is sieve tube.
  • In xylem, only unidirectional movement is possible while in phloem bidirectional movement can occur.
  • In phloem, except phloem sclerenchyma all elements are living.
image 1
FeaturesXylemPhloem
Cells : Living/deadDeadLiving
Cell walls ThicknessThickThin
MaterialLigninCellulose
PermeabilityImpermeablePermeable
Cross wallsNoneSieve Plates
CytoplasmNoneYes
FunctionCarries water and saltCarries sugar
Direction of flowUpwardDown and up
Special FeaturesFiberCompanion cell

ANIMAL TISSUES


A tissue is a group of connected cells that have a similar function within an organism. There are four basic types of tissue in the body of all animals, including the human body.

animal tissue

Epithelial tissues

  • Always grows on some other types of tissue.
  • Cells of epithelium are set very close to each other and the tissue rests on     a non-cellular basement membrane.
  • Consists of single layer of cells.
  • Blood vessels are absent and non-nervous in nature.
  • It covers all the organs and lines the cavities of  hollow organs like stomach.
  • It is primarily protective in function.

Types of Epithelium

Types of Epithelium

Epithelium tissues are classified as :

Squamous epithelium : Also called pavement epithelium.
  • Cells arranged end to end like tiles on a floor.
  • Cells are polygonal in surface view.
  • It forms the delicate lining of cavities (mouth, oesophagus, nose,  pericardium, alveoli etc.) blood vessels and covering of the tongue  and skin
  • Epithelial cells are arranged in many layers (stratum) to prevent wear  and tear in skin.
  • This pattern is stratified squalors epithelium.
Cubical epithelium
  • They are cube like cells that fit closely, cells look like squares in   section, but free surface appears hexagonal.
  • It is found in kidney tubules, thyroid vesicles & in glands (salivary   glands, sweat glands).
  • It forms germinal epithelium of gonads (testes & ovaries).
  • It involves in absorption, excretion & secretion. It also provides   mechanical support.
Columnar epithelium
  • Columnar means ‘pillar-like’ epithelium. It forms lining of stomach.
  • Small intestine & colon, forming mucous membranes.
  • Border of micro villi is present at the free surface end of each cell which increases absorption efficiency in small intestine.
Ciliated epithelium
  • Cells may be cubical or columnar.
  • On its free surface are present protoplasmic outgrowths called cilia.
  • It helps in the movement of ova in the fallopian tube.

CONNECTIVE TISSUE

  • The cells of the connective tissue are widely spaced and embedded in   an intercellular matrix.
  • The mature of matrix decides the function of tissue.
  • White and yellow fibres are present in the matrix.
  • Their basic function is to provide support to different organs & keeping them in place.
Types of CONNECTIVE TISSUE

Fluid or vascular tissue

Blood and lymph

Blood is a connective tissue, fluid matrix of blood is plasma having wandering or floating cells, called corpuscles, blood helps in the  transportation of various materials such as nutritive substances, gases,   excretory products, hormones etc.

Plasma

Form 55% part of blood. Constitution : 90-91% : water, 7% : protein   (Albumin, fibrinogen, globulin), 0.9% : inorganic salt etc.

Corpuscles 

Forms 45% part of blood.

RBCs

They are also called as erthyrocytes, containing red coloured respiratory   pigment called haemoglobin that helps in transportation of oxygen.

WBCs (Leucocytes : They are also called as ‘Soldiers of the body’.)

They are irregular, amoeboid, phagocyte cells that protect our body by   engulfing bacterial & other foreign particles. They are of five types :

Monocytes, Lymphocytes, Basophiles, Neutrophiles, Eosinophils.

Blood platelets or thrombocytes  They are spindle shaped cells which are involved in clotting of blood.

Skeletal Tissue

skeletal tissue the bony, ligamentous, fibrous, and cartilaginous tissue forming the skeleton and its attachments. splenic tissue red pulp. subcutaneous tissue the layer of loose connective tissue directly under the skin.

Skeletal Tissue

It is hard connective tissue that forms supportive framework of the body. It is of two types

Bone

  • Matrix of bone is very hard because of salts such as calcium phosphate,  CaCO3 (60-70%) etc. and a protein ossein.
  • Bone cells (osteoblasts) are embedded in this hard matrix.
  • Matrix is deposited in the form of concentric layers of lamellae formed  round a central canal, the done cells occupy small spaces between the concentric layers of matrix.
  • The long bones are usually hollow containing cavity called as marrow   cavity. It is full of bone marrow.
hard connective tissue

Cartilage

  • This tissue is elastic, less harder as compared to bones.
  • Elasticity is due to presence of chondrin (protein). Cells are called as chondroblast, which are widely spaced and matrix is reinforced by fibres.
  • It occurs at joint of bones, in the nose, ear, trachea & larynx.
  • It provides flexibility and great tensile strength.
bone

Connective tissue

It is the most abundant type of connective tissue. It is further divided into following types :

Yellow fibrous connective tissue

They are very elastic due to the presence of a network of yellow fibres    in its matrix called as ligament which attaches bone to bone.

White fibrous connective tissue
  • They are very little matrix containing abundant white fibres forming layers.
  • Bundles of this tissue are called as tendons, which attaches muscles    to the bones.
White fibrous connective tissue
Aerolar tissue
  • It is the most distributed connective tissue in the body.
  • This tissue fills spaces inside organs and is found between the skin &   muscles, around blood vessels, nerves and in the bone marrow.
Aerolar tissue
Adipose tissue
  • These are oval and round cells, filled with fat globules.
  • The cells are called as adipocytes.
  • It is found in subcutaneous layer below the skin, around the heart, brain   and below the eyeballs. It acts as an insulator and prevents loss of heat   from the body.
Adipose tissue

MUSCULAR TISSUE

Muscular tissue is a specialized tissue in animals which applies forces to different parts of the body by contraction. It is made up of thin and elongated cells called muscle fibers.

  • Movements are brought about in our body with the help of muscular     tissues.
  • They are long fibre-like cells called muscle fibres.
  • They are capable of contraction or relaxation.

Types of Muscular Tissue

Types of Muscular Tissue

Striated muscles

  • They are also called as voluntary muscles because these are under the   control of one’s will.
  • Muscle fibres or cells are multinucleated and unbranched.
  • Each fibre is enclosed by thin membrane which is called as sarcolemma. 
  • Cytoplasm is called as sarcoplasm.
    • These muscles get tired and need rest.

Cardiac muscle fibres

  • They are only involuntary muscles.
  • Only found in the walls of heart.
  • Their structure is in between the striated and non-striated muscles.
  • They are uninucleated and branched. Branches are united by intercalated disc.
  • In these muscles rhythmic contraction and relaxation occurs throughout the life.

Non-striated muscles  

  • They are involuntary muscles also called as smooth muscles.
  • These muscle fibres are uninucleated and spindle shaped.
  • They are not enclosed by membrane but many fibres are joined together in bundles.           
  • Such muscles are found in the walls of stomach, intestine, urinary bladder bronchi, iris of eye etc.
  • Peristaltic movements in alimentary canal are brought about by smooth muscles.

NERVOUS TISSUES

Nervous tissue, also called neural tissue, is the main tissue component of the nervous system. The nervous system regulates and controls bodily functions and activity.

NERVOUS TISSUES
  • They are highly specialized tissue due to which the animals are able to   perceive and respond to the stimuli.
  • Their functional unit is called as nerve cell or neuron.
  • Cell body is cyton covered by plasma membrane.
  • Short hair like extensions rising from cyton are Dendron which are   further subdivided into dendrites.
  • Axon is long, tail like cylindrical process with fine branches at the end. 

    Axon is covered by a sheath

  • Axon of one neuron is very closely placed to the dendrons of another neuron to carry impulses from one to another neuron in the form of electrochemical waves. This close proximity is called as synapse.