Tissues

BIOLOGY TISSUES Tissues
Levels of Organisation

• A cell is the basic structural and functional unit of a living organism. Example: Nerve cell
Cell

• A tissue is a group of cells having a common origin, similar structure and function and held
together by a cementing substance. Example: Connective tissue
Tissue

• Different types of tissues working together and contributing to specific functions inside the
body constitute an organ. Example: Stomach
Organ

• Different organs coordinate to perform a specific life process and form an organ system.
Organ Example: Digestive system
system

• Various organ systems working simultaneously together constitute an organism.
Example: Plants
Organism

Differences between Plant and Animal Tissues

PLANT TISSUES ANIMAL TISSUES

1. Dead supportive tissues are more 1. Living supportive tissues are more
abundant as compared to living abundant as compared to dead
tissues. tissues.

2. Require less maintenance energy. 2. Require more maintenance energy.

3. Differentiation of meristematic and 3. No differentiation of meristematic and
permanent tissues. permanent tissues.

4. Organisation is simple. 4. Organisation is relatively complex.

5. Tissue organisation is meant for 5. Tissue organisation is meant for high
stationary habit of plants. mobility of animals.

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BIOLOGY TISSUES
Classification of Plant Tissues

Meristematic Tissue

Characteristics Location Function

•Cells are thin-walled •Located at the tips of •The cells of
and composed of the roots and stems,
cellulose. and the base of the meristematic tissue
node, internode or
leaf. divide actively, which

results in growth

(increase in thickness

and length) of plants.

Types of Meristematic Tissues

Type Location Function
Apical meristem
Located at the growing points of the stem, Enables the root and stem to
Intercalary roots, branches and in growing young leaves grow by increasing the length of
meristem near the tips of stems and axillary buds plants
Located at the internodes or stem regions The cells are active and they
Lateral between the places at which the leaves attach continuously form several new
meristem/ and at leaf bases cells
Cambium
Present laterally (on the sides) on the roots and The girth and
stem and is situated parallel to the longitudinal width/diameter/thickness of the
axis below the bark stem or root increases because of
the lateral meristem

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BIOLOGY TISSUES

Permanent Tissues

 Permanent tissues are formed by the division of the meristematic tissue cells which have lost their
ability to multiply.

Types of Permanent Tissues
Protective Tissue
 It is found on the surface of the roots, stems and leaves.
 It consists of cells with thick walls.
 It provides protection against mechanical injury or invasion by parasitic fungi.

Types of Protective Tissues

Type Characteristics Location Function
Epidermis
Cells are elongated and Present in the outermost Protects the plant from
Cork flattened with no intercellular layer of leaves, flowers, desiccation and
spaces between them. stem and roots. infection.

Cells are rectangular with It is the outermost layer Prevents desiccation,
vacuolated protoplasts.
formed after the epidermis infection and mechanical

undergoes certain changes. injury.

Supporting Tissue
 It provides support to the plant.

Types of Supporting Tissues

Type Characteristics Location Function
Parenchyma Provides temporary
Consists of relatively non- Mainly present in the soft support and maintains
Collenchyma the shape of the plant
specialised large, thin-walled parts of the plant and outer body
Sclerenchyma Provides mechanical
living cells cortical region of roots and support and elasticity to
young dicotyledonous
stems plants
Provides strength and
Cells are living and elongated Located in non-woody toughness to plant parts

with cell walls irregularly plants, leaf stalks and

thickened at the corners below the epidermis of the

stems and veins of leaves

Consists of elongated, narrow Located in the stems

and fibre-like cells. around the vascular bundle,

Cells are dead, pointed at veins of leaves and hard

both ends and thickened covering of seeds and nuts

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BIOLOGY TISSUES

Conducting Tissue (Vascular Tissue)
 It is present in stems, roots and leaves.
 It provides a passage for water and dissolved materials to move up and down in the plant body.

Types of Conducting Tissues

Type Characteristics Location Function
Xylem Provides upward
Complex permanent tissue Present in the stem, roots movement of water and
Tracheids dissolved materials
with thick-walled cells; most of and leaves
Provide a network of
the cells are dead hollow and connected
cells for the transport of
Components of Xylem water
Allow free flow of water
Made of elongated cells with - and minerals from the
flat and tapering ends roots to the leaves
Stores food in the plant
Xylem vessels Tubular structures which - body
consist of dead cells Mainly support the plant

Xylem Consists of living parenchyma - Function
parenchyma Provides a passage for
Xylem fibres cells associated with xylem the downward movement
of food
Type Separated by thin cross walls -
Phloem Translocation of organic
Types of Conducting Tissues substances
Help to control the
Characteristics Location activity of sieve tube
elements
Complex permanent tissue Lies just beneath the bark Provide mechanical
strength to plants
of the tree Transports food from the
leaves to the other non-
Sieve tubes Components of Phloem green parts of the plants
Tubular cells with perforated -
Companion walls and arranged end to end
cells Cells are living and keep their -
nuclei and other organelles
Phloem fibres throughout their life
Elongated, tapering and dead Found particularly in the
Phloem cells with thickened cell walls stem
parenchyma Cells are alive and filled with -
cytoplasm

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BIOLOGY TISSUES
Differences between Meristematic and Permanent Tissues

MERISTEMATIC TISSUE PERMANENT TISSUE

1. Simple tissue 1. Simple, complex or specialised tissue
2. Component cells are small, 2. Component cells are large,

spherical or polygonal and differentiated with different shapes
undifferentiated
3. Intercellular spaces are absent 3. Intercellular spaces are present
4. Cells grow and divide regularly 4. Cells do not divide
5. Metabolically active 5. Metabolic rate is slow
6. Provides protection, support,
6. Provides growth to the plant
conduction, photosynthesis, storage

Classification of Animal Tissues

Epithelial Tissue

Characteristics Location Function

•Flat, cuboidal or •Covers the whole body •Protection, absorption,
columnar cells surface secretion, sensory
perception

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BIOLOGY TISSUES

Types of Epithelial Tissues

Type Characteristics Location Function
Simple Cells are large,
squamous extremely thin and flat Lining of blood vessels, lung Transport of substances
epithelium alveoli, oesophagus, the lining of through a selectively
Stratified Cells are arranged in the mouth and cheek permeable membrane
squamous a pattern of layers Outer protective covering all over Provides protection to
epithelium the body surface underlying tissues
Columnar
epithelium Cells are tall and Inner lining of the Absorption of nutrients from
Ciliated cylindrical-like pillars stomach and intestines the digested food
columnar Cells possess fine Inner lining of the trachea, lungs, In the respiratory tract, the
epithelium hair-like cilia respiratory system and buccal movement of cilia pushes the
Cuboidal chambers mucus forward to clear it
epithelium Cells are cube-shaped Lining of the kidney tubules as well Helps in the absorption of
and are placed on a as in the ducts of the salivary useful material from urine
Glandular basement membrane glands before it is passed out
epithelium Epithelial tissue which
folds inwards to form Present in the stomach, intestine Synthesis and secretion of
a multicellular gland and pancreas substances at the epithelial
surface

Connective Tissue

Characteristics Location Function

•Consists of a matrix and •Found in the deeper parts •Connects various organs
the cells are embedded in it of the body, between the and keeps them in place
skin and muscles

Types of Connective Tissues
Connective Tissue Proper/Loose Connective Tissue
 It is composed of irregular cells scattered and embedded in a soft matrix and encompasses all internal

organs and body cavities.
 It acts as a binding and supporting structure within the body.

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BIOLOGY TISSUES

Types of Connective Tissues Proper

Type Characteristics Location Function
Areolar Supports and strengthens the
tissue Made of gelatinous matrix Found between the skin and internal organs

Adipose containing cells and muscles, around the blood Insulates the body and
tissue prevents the loss of heat
irregularly arranged fibres vessels, nerves and in the bone
Fibrous Tendons help to attach
tissue marrow muscles to the bones.
Ligaments serve to hold the
Cells are filled with fat Found beneath the skin, around structures together and keep
them strong and stable
globules the kidneys and other internal

organs such as intestines

Mainly formed of fibre- Found in the spaces between the

forming cells, which form bones and muscles

the tendons and

ligaments

Supportive Connective Tissue/Dense Connective Tissue
 It is composed of fibres as its main matrix element and is found in bones and cartilages.
 It connects different tissues.

Types of Supportive Connective Tissues

Type Characteristics Location Function
Cartilage
Non-porous, semi- Present in the nose, external ear, Smoothens the bone surface
Bone
transparent and elastic trachea, larynx, ends of the long at joints, allowing smooth

tissue bones and between the vertebrae movement of these joints

Hard, strong and non- Forms a rigid part of the skeletal Forms the supporting

flexible porous tissue system framework of the body

which consists of living Gives shape and rigidity to

cells the body

Fluid Connective Tissue
 It consists of liquid as the ground substance and is present throughout the body.
 It provides nutrition, helps in transport of nutrients and gets rid of waste matter.

Types of Fluid Connective Tissues

Type Characteristics Location Function
Blood Connects different parts of
Red-coloured fluid matrix which Present throughout the the body and establishes
Lymph consists of plasma and cells such body continuity within the body
Transports nutrients and
as RBCs, WBCs and platelets provides protection against
diseases
Fluid surrounding the body cells Present throughout the

which contains WBCs body

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BIOLOGY TISSUES Location Function

Muscle Tissue •Mostly attached to the •Helps in contraction and
bones relaxation of the body
Characteristics
•Consists of elongated,
narrow, muscle cells
called muscle fibres

Types of Muscle Tissues

Type Characteristics Location Function
Found attached to the Help in voluntary muscle
Striated/skeletal/ Muscle fibres are long, bones movement and locomotion
striped/voluntary cylindrical, unbranched
muscles and multinucleate Found in the uterus, Carry out movements
digestive tract, urinary which cannot be carried
Non-striated/ Muscle fibres are bladder, iris of the eye, out by our conscious will
bronchi of the lungs and
smooth/non-striped/ smooth and without other internal organs Rhythmic contraction and
Found only in the walls of relaxation of cardiac
involuntary muscles striations the heart muscles help to pump and
distribute the blood to
Cardiac/heart Muscle cells are short, various parts of the body
muscles cylindrical and have a
single, centrally placed
nucleus

Differences between Smooth, Skeletal and Cardiac Muscles

SMOOTH MUSCLE SKELETAL MUSCLE CARDIAC MUSCLE

1. Not striated 1. Striated 1. Striated
2. Spindle-shaped 2. Cylindrical 2. Cylindrical
3. Not branched 3. Not branched 3. Branched
4. Nucleus - central 4. Nuclei - peripheral 4. Nuclei - central
5. No discs 5. No discs 5. Intercalated discs
6. Involuntary 6. Voluntary 6. Involuntary
7. Slow 7. Fast 7. Fast
8. Contraction not inherent 8. Contraction not inherent 8. Contraction inherent

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BIOLOGY TISSUES Location Function

Nervous/Neural Tissue •Component of the •Nerve cells mediate the
nervous system and transmission of messages
Characteristics encompasses the brain, from the brain to different
•Made up of elongated spinal cord and nerves parts of the body and vice
cells called neurons versa
•Each neuron consists of
three parts—cell body,
axon and dendrites

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