Tissues ppt. 2

PLANT TISSUES

Group of cells having a common origin similar or related structure which work together to perform a common function.

HISTOLOGY – Study of Tissues Plants and animals have similar life processes but

they do not have similar tissues. Because of the differences in organisation,mode of

living and life style.

TISSUES

Plants : Continue to grow throughout their life. Possess meristematic tissues in specific

regions of body for growth. Animals:

Mobile, move in search of food, shelter, etc. Tissues are living. Living tissues require more energy for

maintenance. Stop growing after maturity No meristematic tissues In having organ and organ system, structural

organisation of animals is far more specialised and localised as compared to plants because of mobility and different feeding methods.

PlantsStationary, require supportive tissues for structural strength.Most tissues are dead, provide mechanical strength and requires less maintenance.

PLANT TISSUES (2 TYPES)

PLANT TISSUES

Meristematic Tissue

(i) Apical

(ii) Intercalary

(iii) Lateral

Permanent Tissue

Simple Permanent

(i) Parenchyma

(ii) Sclerenchyma

(iii) Collenchyma

Complex Permanent

(i) Xylem

(ii) Phloem

Special Tissue

(i)Protective

(ii) Glandular

Thin walled, compactly arranged, immature cells - have the potential to divide and form new cells.

Meristem cells – Meristematic cells Region where present – functions as growth

region. New cells produced by meristems – meristematic

cells - grow slowly, differentiate and mature into components of various permanent tissues

MERISTEMATIC TISSUE (also called meristem)

Shape and size – small, spherical or polygonal in outline.

Cell wall – thin, elastic Intercellular space – absent, cells are compactly

arranged. Cell contents:

Nucleus is large. Cytoplasm is dense. Vacuoles are absent or very small.

Activity: Respiration is rapid. High synthetic activity. Food supply is high but not stored. Cells grow and divide repeatedly.

CHARACTERISTICS OF MERISTEMATIC CELLS

Parent tissue – Parent tissue from which other tissues develop.

Growth – takes part in growth by formation of new cells.

New Organs – plants continue to produce new leaves, stem branches, flowers, fruits, root hairs and root branches. They are formed by meristematic cells.

Injury – place of injury is healed by the formation of new cells.

Lodging – The shoots lodged or bent by wind are made to grow upright by activity of intercalary meristem.

FUNCTIONS OF MERISTEMATIC TISSUES

LOCATION OF MERISTEMS

Based on position in plant body, meristematic tissues are of 3 types: (i) Apical, (ii) Intercalary, (iii) Lateral

Apical Meristem: Occurs in growing tips of stems and

roots. Depending upon its occurrence, it is

called: Root tips – root apical meristem Stem or shoot tips – stem or shoot apical

meristem Produces growth in length of root and

stem. Intercalary Meristem:

Occurs in intermediate position: At the base of leaves, At the base of internodes (eg. Grasses), or, Below the nodes (eg. Mint)

LOCATION OF MERISTEMS

Intercalary Meristem: Helps in growth of leaves and

internodes. Upward bending of lodged shoot is

made uptight due to intercalary meristem.

It is the left out part of optical meristem.

Lateral Meristem: Occurs on the sides of both stem and

roots. Increases the girth of stem and root. Two types:

Vascular Cambium – Produces secondary vascular tissues, secondary phloem, secondary xylem.

Cork Cambium – Produces protective cork on the outside.

MERISTEMATIC TISSUES

NODES AND INTERNODES

Group A Q 1. Name the different types of meristematic tissues. Q 1. What type of meristematic tissue is observed in the

roots of the onion? Group B

Q 1. Consider the meristem being experimented with in the activity. Mention the functions of this meristem performed in a plant.

Group C Q 1. What do you expect the end result of the activity to

be?

WORK SHEET

PERMANENT TISSUES

Permanent Tissue

Simple Permanent

(i) Parenchyma

(ii) Sclerenchyma

(iii) Collenchyma

Complex Permanent

(i) Xylem

(ii) Phloem

Special Tissue

(i)Protective

(ii) Glandular

Differentiation of Meristematic tissues: Meristematic tissues have lost the ability to divide,

and have assumed a permanent shape, size and function –DIFFERENTIATION.

Permanent tissues are formed due to differences in their specialisation.

Permanent tissues are: Simple Permanent Complex Permanent Special Permanent

PERMANENT TISSUES

Shape and Size: Cells have definite shape and size, which do not alter afterwards.

Specific functions: Permanent cells come to have specific functions.

Wall: Thin or thick. Thickening can be regular or irregular.

Division: Normally do not divide. Life: May be living or dead.

CHARACTERISTICS OF PERMANENT TISSUES

Meristematic Tissue Permanent Tissue

• Nature: Cells are small, isodiametric and undifferentiated.

• Cells are large, differentiated with different shapes.

• Spaces: Intercellular space absent.

• Intercellular places often present.

• Vacuoles: Nearly absent. • Large central vacuole in living permanent cells.

• Nucleus: Large and prominent.

• Less conspicuous.

• Wall: Cell wall is thin. • Cell wall is thin or thick.

• Division: Cells undergo regular divisions.

• Cells do not normally divide.

• Tissue: Meristematic tissue is a simple tissue.

• Can be simple, complex or special.

• Organelles: Cell organelles are simple.

• Cell organelles are well developed.

DIFFERENCES

Cells of Simple Permanent tissues are similar in structure, origin and function.

Three types of Simple Permanent tissues: Parenchyma Collenchyma Sclerenchyma

SIMPLE PERMANENT TISSUE

Parenchyma: Thin walled, made up of cellulose. Relatively unspecialised. Isodiametric Living cells lying in between specialised tissues. Most abundant tissue. Found in all non-woody parts like stem, root, flowers,

fruits. Cells are oval, spherical or polygonal in outline. Central vacuole, peripheral cytoplasm and nucleus. Loosely packed with small and large intercellular space.


Functions of Parenchyma: Storage: Stores food and water. Cells are specially enlarged to store nutrients and

water. Support: Cells remain turgid and provide rigidity to

softer parts. Gaseous exchange: Intercellular spaces present,

allows movement of gases and gaseous exchange. Waste Products: Certain cells store waste products

like tanning resins , gums, crystals, etc.


Functions of Parenchyma (cont.) Transport: Parenchyma in xylem and phloem takes part

in slow, lateral movement of materials. Chlorenchyma: Parenchyma containing chloroplast -

seat of photosynthesis. Aerenchyma: A network of parenchyma cells encloses large air cavities Store gases and provides buoyancy to acquatic plants. Epidermis: Specialised parenchyma present on the

surface of plant organs.


Collenchyma: Simple permanent, living, mechanical tissue. Provides flexibility to soft aerial parts that bend without

breaking (Eg. Leaves, young stems). Cell wall is thickened unevenly at the corners Thickening made up of pectin and cellulose. Intercellular spaces are little. Cells are elongated but appear oval, circular or angular in T.S section. Occurs below the epidermis in leaf stalks, leaf mid ribs

and herbaceous dicot stems. Absent in monocots


Functions of Collenchyma: Strength: Provides mechanical strength and

flexibility. Because of Collenchyma plant organs can bend without breaking.

Growth: allows growth and elongation of organs.

Storage: being a living tissue, it stores food. Photosynthesis: cells may contain

chloroplast and take part in photosynthesis.


Sclerenchyma: Long, narrow, dead and highly thick-walled with little

lumen (internal space) Thickening is made of – Lignin Lignin functions as cement and hardens the cells. The walls contain certain unthickened areas – pits. Sclerenchyma occurs in – stems of monocot plans,

around vascular bundles – xylem and phloem. Hard covering of nuts, husk of coconut, grit of apple, pear and guava.


Functions of Sclerenchyma: Mechanical Strength: Chief mechanical tissue

providing strength to the plants - enables them to bear various stresses.

Protection: Forms a protective covering around seeds and nuts.

Commercial fibres: Sclerenchyma fibres of some plants are commercially exploited, e.g. Flax, Hemp, Jute, Coconut.


SIMPLE PERMANENT TISSUES

Identify the Figures 1 2 3

Group A :Identify the above figuresGroup B:In the above figures, name the living and non living tissuesGroup C:Name the tissue present in the bark of the tree. How is it useful tothe plant?

Protective Tissue Outer layer of cells (stem, root, leaves, flowers, fruits, etc.) Providing protection against adverse environmental factors and

pathogens. Performs specialized functions – like exchange of gases. Types: EPIDERMIS AND CORK

Epidermis: Outermost, protective layer in plant organs. Commonly single layers Cells are elongated and closely packed. Intercellular spaces absent. Generally thickened on outer and radial sides and thin walled on the inner

side.

SPECIAL TISSUE

Epidermis (cont.) In aerial parts, the outer thick walls (Cellulose) covered by a

layer of water impermeable fatty substance – CUTIN Cutin and Wax form a separate non-cellular coating – CUTICLE At some places (like leaves), aerial parts bear minute pores

called stomata. Each stoma is enclosed by a pair of specialised epidermal cells

called guard cells. Guard cells – are kidney shaped (dicot) or dumb-bell shaped

(monocot) Guard cells are thicker on the inside and thinner on the

outside The pores are helpful in exchange of gases Pores are seat of transpiration In roots, epidermal cells give rise to tubular outgrowths called

root hairs.

SPECIAL TISSUE

Epidermis (cont.) Root hairs increase the absorption by increasing the surface

area of the root.

SPECIAL TISSUE

Functions of Epidermis: Protection – against pathogens and pests Water loss – checks water loss because of the cuticle Epidermal Hair – produces insulating stationary layer of

air. Stomata – Regulate exchange of gases Seat of major water loss in transpiration Transpiration keeps aerial parts cool Epidermis of the root along with root hairs absorb water

and minerals

SPECIAL TISSUE

Cork: Outer protective tissue of older stems and roots Formed by secondary lateral meristem called cork cambium Rectangular in outline Compactly arranged in several layers Intercellular space – absent Older cells – dead and filled with tannins, resins and air Their walls become impermeable due to deposition of Suberin Commercial cork – obtained from stems of Cork Oak

SPECIAL TISSUE

Functions of Cork: Protection against loss of Water Protection from microbes Insulation against mechanical injury,

extremes of temperature, fire and browsing animals

Commercial use – stoppers for bottles, shock absorber insulation boards, sports goods, etc.

SPECIAL TISSUE

Permanent tissues made of more than one type of cells

Work together to perform one particular function Conducting or Vascular tissues – survival of the

plant is possible as they carry materials inside the plant

Types Xylem Phloem

COMPLEX PERMANANENT TISSUE

Xylem: Takes part in conduction of water and mineral salts Provides mechanical strength Also called wood Four elements: (a) tracheids, (b) vessels, (c) xylem

fibres, (d) xylem parenchyma Tracheids:

Long, tubular dead cells with lignified walls and tapering ends Possess various types of thickening for mechanical strength Unthickened areas help in movement of water from one

tracheid to another


Xylem (cont.) Vessels:

Long tubules Walls are lignified Occur in flowering plants More efficient than tracheids Formed by end to end union of large number of dead cells Vessels and tracheids are conducting elements of xylem. They conduct

water and minerals vertically Xylem fibres:

Sclerenchyma fibres found in xylem Have thick pitted walls, narrow lumen and tapering ends Cells are dead Provide mechanical strength


Xylem (cont.) Xylem parenchyma:

Consists of living cells Present inside xylem Stores food Helps in lateral conduction

Functions of Xylem: Conducts water and minerals from roots to the top of plants. Movement

is unidirectional Provides mechanical strength because of the occurrence of thick walled

lignified components Wood is mostly made of xylem Xylem parenchyma is the only living tissue – helps in lateral conduction

of water and storage of metabolic waste


Phloem: Takes part in conduction of organic food Living conducting tissue because of the living cells in

its transport channels Four elements – (a) Sieve tubes (b) Companion cells (c) Phloem parenchyma (d) Phloem fibres


Sieve Tubes: Elongated, living, tubular conducting channels Transverse end walls between adjacent sieve tubes cells are

perforated – sieve plates Have vacuolated cytoplasm Nucleus degenerates Cytoplasmic strands are continuous between adjacent sieve

tubes


Companion cells: Thin walled, small and elongated Has dense cytoplasm and nucleus Nucleus controls the sieve tubes and keeps them living

Phloem parenchyma: Parenchyma present in phloem Thin walled and living Function – storage and slow lateral conduction of food


Phloem fibres: Only non-living component of phloem Thick walled, elongated, spindle shaped Dead cells, which possess narrow lumen Provide mechanical strength to the tissues


Phloem (cont.) Functions:

Transports organic food throughout the plant Conduction occurs in both directions Phloem fibres of some plants are sources of

commercial fibres (E.g. Jute, Hemp, Flax)


Differences between xylem and phloem


Xylem Phloem

• Conduction: Conducts water and minerals

• Conducts organic solutes or food materials

• Direction: Mostly unidirectional • Can be bidirectional

• Components: Tracheids, vessels, xylem parenchyma, xylem fibres

• Sieve tubes, companion cells, phloem parenchyma, phloem fibres

• Channels: Conducting channels are tracheids and vessels

• Conducting channels are sieve tubes

• Dead / Living parts: Tracheids, vessels and xylem fibres are dead elements. Only xylem parenchyma is a living element

• Sieve tubes, companion cells and phloem parenchyma are living elements. Phloem fibres are the only dead elements

• Mechanical Strength: In addition to conduction, xylem provides mechanical strength to the plant

• There is no mechanical function

Occur in holozoic organisms. On the basis of structure and functions

ANIMAL TISSUES

Animal Tissues

Epithelial Tissue Connective Tissue

Muscular TissueNervous Tissue

Fundamental animal tissue. Forms a continuous sheet of closely packed cells. Covers the entire external and internal surface of

the animal body. Intercellular space is absent Cells are tightly held together by small amount of

cementing material. Epithelium rests over an extra cellular layer of

collagen fibres and dense matrix – BASEMENT MEMBRANE.

EPITHELIAL TISSUE(Epithelium-Plural)

Basement membrane connects the epithelial tissue to the underlying connective tissue.

A direct vascular supply is absent. Forms a barrier for separating the different body

system. Anything entering the body must cross atleast one

layer of epithelium. Permeability of various epithelial cells determines the

passage of substances between different body parts and between body and external environment.

Occurs over – skin, lining of mouth,parts of alimentary canal, lung alveoli, lining of respiratory tract, reproductive tract, blood vessels and different types of glands.


FUNCTIONS: 1.Protection:Epithelium lying over the skin

protects the body from drying up, microbes and chemical injury.Similar protection is carried out by in in the lining of the mouth, nasal tract, and alimentary canal.

2.Absorption: Some epithelium have become specialized for absorption. Eg. Intestinal mucosa.

3. Excretion: Epithelium lining the different parts of kidney tubules take part in ultra filtration, secretion and reabsorption to produce urine.

4.Exchange of gases: In the lining of the lung alveoli allows diffusion of gases between blood and alveolar air.


FUNCTIONS: 5.Movement:Epithelium having cilia help in

movement of various types of materials. Eg. Dust particles and mucus in respiratory tract, ovum in oviduct, urine in urineferous tubules, etc.

6.Secretion: Glandular epithelium produces secretions. Eg. Tear, gastric juice, mucus, intestinal juices.

7.Germinal Epithelium: Produces male and female sex cells.

8. Sensations: Sensory epithelium is specialised to receive sensations.Eg. Nasal epithelium, taste buds.


On the basis of arrangement of layers, cell shapes and functions Epithelial tissues are classified as:


Epithelium

Arrangement of Layers1.Simple

Epithelium2.Stratified Epithelium

Cell Shape1.Squamous Epithelium2.Cuboidal Epithelium3.Columnar Epithelium

Functions1.Ciliated Epithelium2.Glandular Epithelium3.Sensory epithelium4.Germinal Epithelium

Simple epithelial tissues- cells are arranged in single layer

Stratified epithelial tissues- cells are arranged in more than one layer

Squamous epithelial tissues -also called – Pavement Epithelium – cells are arranged like the tiles of the floor.-cells are thin, flat, polygonal with bulging centre and

flat nuclei.- Margins my be smooth or wavy.


Simple Squamous epithelium : - Functions as selectively permeable barrier allowing

diffusion, filtration, and secretion.-occurs in Lung alveoli, blood capillaries, Bowman's

capsules.Stratified Squamous epithelium :-occurs in areas where there is wear and tear of

tissues.Eg. buccal cavity, Pharynx, oesophagus, skin.The basal layer lying in contact with basement

membrane continues to add new cells as the older surface are torn away.



Cuboidal Epithelium : Compactly arranged cells Cuboidal in shape Nucleus is rounded and centrally placed Occurs in salivary ducts, kidney tubules, pancreatic

ducts, thyroid vescicles , endocine glands – providing mechanical support.

Acquire additional specialization as gland cells for secretion, absorption and excretion

Sometimes aportion of the cuboidal epithelium gets folded inwards to form multicellular gland – Glandular epithelium.


Columnar Epithelium : Consists of tall, pillar like, compactly arranged cells,

oval nucleus lying near the base. Facilitates movement across the epithelial barrier Takes part in secretion and absorption in the lining of

the stomach, intestine and their glands. Columnar epithelial cells in the respiratory tract have

cilia – CILIATED EPITHELIUM Cilia pushes the mucus forward and clears it.


Fundamental animal tissueEmbedded in an abundant matrix Matrix helps in connecting, binding,

packing and supporting different structures of the animal body.

Matrix may be jelly like, fluid , solid- dense or rigid.

On the basis of nature of matrix types of connective tissue are:

CONNECTIVE TISSUE

Connective tissue

CONNECTIVE TISSUE

1.Areolar Tissue

2.Adipose Tissue

3.Ligament4.Tendon

Skeletal Tissues

1.Cartilage2.Bone

Vascular Tissues

1.Blood2.Lymph

Areolar Tissue: Connective tissue found between skin and muscles,

around blood vessels and nerves in bone marrow. Fills the space inside the organs.FUNCTIONS:1.Supports internal organs2.Helps in repair of tissues3.Produces antibodies and other chemicals to combat microbes.

CONNECTIVE TISSUE

Adipose Tissue: Connective tissue found below the skin and between the internal organs.

Cells of the tissues are filled with fat globules.FUNCTIONS:1.Stores fat it is kept as a reserve and used when required.2.Storage of fat makes it act as an insulator.3.Forms shock absorbing cushions around the organs.4.Rounds of body contours and provides shape to

various parts of the body

CONNECTIVE TISSUE

Skeletal Tissues:1.Bones: forms the frame work supporting the

body Anchors the muscles and supports the main

organs of the body. Strong, non-flexible tissue. Cells are embedded in a hard matrix. Matrix is composed of calcium and phosphorous.

CONNECTIVE TISSUE

Skeletal Tissues:Bones: FUNCTIONS:1.Forms the frame work2.Protects the vital organs like heart, lungs, brain, etc.3.Takes part in body movements including locomotion

CONNECTIVE TISSUE

Skeletal Tissues : 2.Cartilage: Has widely spaced cells, solid matrix composed

of proteins and sugars. Smoothens bone surfaces at joints. Present in nose, ear, trachea, larynx, etc.

CONNECTIVE TISSUE

Skeletal Tissues: 2.Cartilage:FUNCTIONS:1.Provides support and flexibility to various body parts.eg.

Ears2.Prevents frictional wear and tear of the bones.3.Acts as a cushion against stresses in the vertebral discs.

CONNECTIVE TISSUE

LIGAMENT: Two bones are connected to each other by ligament. Elastic in nature. Has considerable strength. Contain very little matrix. Over stretching causes sprain.TENDONS: Connects muscles to bones Fibrous tissue, has great strength,limited flexibility

CONNECTIVE TISSUE

Vascular Tissues: 2 types.1.Blood: has fluid matrix – Plasma RBC, WBC and platelets – suspended in plasma Plasma contains salts, proteins and hormones.FUNCTIONS:1.Blood flows and transports gases, digested food,

hormones and waste products to various parts of the body.

2.Conducts heat and regulates the body temperature.3.Keeps the tissue moist.4.WBC fight against microbes by producing antibodies.

VASCULAR TISSUE

2.Lymph: Fluid lying in the empty spaces. Light yellow fluid connective tissue. Brings in CO2 and wastes from tissues to

blood. Carries O2, nutrients and hormones from

blood to tissues. Returns proteins and excess fluid to the

circulation. Picks bacteria and brings them to lymph

nodes and destroy them. Transports fat from digestive system.

VASCULAR TISSUE

Consists of elongated cells Also called as muscle fibers Responsible for movements in our body Contains special proteins - contractile protein Contractile protein – causes movement by

contracting and relaxing.

MUSCULAR TISSUE

Striated / Voluntary Muscles: Voluntary Muscles - moves by our consciouswill.

Eg. Limb Muscles. Also called as Skeletal muscles – attached to bones

for movement. Have light and dark bands or striations – Striated

muscles. Striated muscle tissues – cells are long, cylindrical,

unbranched, multi nucleated.

MUSCULAR TISSUE

Smooth / involuntary Muscles: Movement cannot be controlled by us. Also called smooth or unstriated muscles as there

are no striations. Occurs in alimentary canal, blood vessels, ureters,

iris of the eye, bronchi of lungs. Cells are long with pointed ends, spindle shaped,

uni nucleated

MUSCULAR TISSUE

Cardiac Muscles: Muscles of heart show rhythmic contraction and

relaxation through out the life. Involuntary muscles- movement cannot be

controlled by us. Cardiac muscles – cylindrical, branched ,

uninucleated, faint striations are seen

MUSCULAR TISSUE

Cells possess the ability to respond to stimuli. Highly specialized - Being stimulated and

transmitting the stimulus very rapidly in the body. Also called as neurons. Occurs in brain, spinal cord, and nerves.

NERVOUS TISSUE

Structure of neuron: Consists of a cell body, nucleus and Cytoplasm. Long hair like structures arise from cytoplasm . Axon - single long part . Dendrites – many short branched parts. Individual cells - 0ne metre long. A nerve - Many nerve fibers bound together by connective tissue. Nerve impulses allow us to move our muscles when we want to. Combination of nerve and muscle tissue enables animals to move rapidly in response to stimuli.

NERVOUS TISSUE

NERVOUS TISSUE

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Tissues ppt. 2

Education