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ANIMAL TISSUES
ANIMAL TISSUES

EPITHELIAL TISSUE

MUSCULAR TISSUE

NERVOUS TISSUE

CONNECTIVE TISSUE

EPITHELIAL TISSUES
Characteristics of epithelial tissues
1
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3
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5
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7
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It always rests on non cellular nonliving gelatinous layer called basement membrane
...

It is non nervous in nature
...

The cells may be present in a single layer or in many layers one above the other
...


Functions:
1
...

2
...
(e
...
, glandular epithelium)
3
...

4
...
g
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5
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g
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6
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7
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1

Squamous Epithelium
Nature: It is composed of 'a single layer of thin and flat, plate-like cells
...
These cells form a sheet-like structure with mosaic appearance
...
g
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Functions
1
...


2
...


Cuboidal Epithelium
Nature: Its cells are cube-shaped, isodiametric and closely fitted together
...

Occurrence : It is found in some parts of kidney tubules and ducts of salivary glands, thyroid gland, sweat
glands & exocrine glands like pancreas
...
Here it is known as
germinal epithelium
...
It helps in absorption, secretion & excretion
...
It provides mechanical support
...
Nuclei are placed

near the base at the same level
...

Function: It helps in absorption of nutrients in intestines, secretion in stomaxch & intestines, secretion of
mucous secretory glands
...

Occurrence: This is found in the trachea (wind pipe), bronchi (in lungs) and bronchioles (branches of wind
pipe), kidney tubules, sperm ducts and fallopian tubes (oviducts)
...
, from the lungs to the exterior
...


Depending upon functions performed by simple epithelial tissues it is further classified into five
types
1
Glandular epithelium
Some of the columnar epithelial cells of the epithelium change into glandular cells
...
This is glandular epithelium
...
, secreting mucous, enzymes and hormones
...


2

Sensory epithelium

These epithelial tissues are found in the sensory organs
...

3
Germinal epithelium
They are found in the gonads & are responsible for producing gametes
...

5
Ciliated epithelium
Causes movement by beating of cilia
...


Muscle Tissues (or Muscular Tissues)
The movement of internal organ such as heart and alimentary canal are caused by these tissues
...
allowing them to work together effectively
...
The muscular tissue is formed of greatly elongated and highly contractile tissues
and muscles cells which are called muscle fibres
...

Functions
1
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Locomotion

3
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Increasing and decreasing size of cavities or lumen of hollow organs
5
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Beating of heart

Straited muscles
These muscles are also known as striped, skeletal or voluntary muscles
...
Since these muscles are attached to the bones in different parts of the
body and hence are responsible for body movement, they are called skeletal muscles
...
It consists of a thin outer
limiting membrane, called sarcolemma, which encloses a coenocytic plasma, known as sarcoplasm
...
In the sarcoplasm (cytoplasm) of the muscle cell are embedded a large
number of contractile element, called myofibrils running parallel to one another lengthwise
...
g
...
These
are also present in the abdominal wall in the form of sheets, diaphragm, tongue, pharynx and these are called
visceral striated muscles since these are found in internal (visceral) organs
...
These muscles are strong and powerful and undergo rapid contraction and expansion
...
These muscles provide force for locomotion and all other voluntary movements of the body parts
...
Tongue movements are brought about by striped muscles
...
The cell structure is relatively simple
...
These are held together by loose connective
tissues
...
It consists of a long cigarshaped nucleus in the centre of cytoplasm or sarcoplasm
...
The fibres have no striations or bands across muscles hence, are called smooth or
unstriated muscles
...

Functions:
1
...
Movement of food in the alimentary canal or opening and closing of cavity are involuntary
movements
...
These are independent of voluntary control except the ciliary muscle of the eye
...
They show slow and sustained contraction and relaxation (i
...
peristaltic movements which push the food
onward)
...

4
...


Cardiac muscles
Nature: These muscles resemble striated muscles but, functioning independently of he conscious control of brain,
these are involuntary like the smooth muscles
...
Each fibre is surrounded by very thin sarcolemma and has cytoplasm (sarcoplasm)
...
e
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The intracellular spaces of
cardiac muscles are filled with abundant loose connective tissues richly supplied with blood capillaries
...
The ends of these fibres have
zig-zag junctions, called intercalated disc
...
These are
regions of interdigitation of sarcolemmas of adjacent muscles or fibres (i
...
, each fibre of cardiac muscles is formed
due to joining of individual uninucleated muscle cells to one another in a linear arrangement)
...

Functions:
1
...

2
...


It is formed of spindle shaped cells
...


2

Its fibers are arranged in
bundles
...


Its fibers are arranged in the
form of network
...


Sarcolemma is absent
...


4

Myofibrils are large & show
alternate light & dark bands
...


Myofibrils are large & show
alternate light & dark
bands
...

They are found attached to the
limbs, tongue,& body wall
...

They occur in the walls of the
organs like alimentary canal, blood
vessels etc
...


Each cell is uninucleated
with nucleus in the centre of
the cell
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Do not get fatigued soon
...

Soon get fatigue
...


Nervous tissue

5

Nature: A tissue which is specialised for receiving and transmitting messages in our body is nervous tissue
...
The nervous tissue is composed of specialised cells
or nc uro,ns
...
The signals or impulses travel from one neuron to the other
...
Cell body or cyton is bounded by a thin cell membrane, enclosing the cytoplasm, called nucleoplasm
...

2
...
They conduct impulses into the cyton
from the receptor organs
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Axon is single, thick and large
...
Axon is also known
as nerve fibre
...
i
...
, to effector organs (muscles)
...


Connective tissue
This tissue connects various part of the body
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The number of cells is few
...
Large intercellular spaces
...
Ground substances called matrix fills the intercellular spaces
...
White & yellow fibers present in the matrix
...
It consists of a transparent
jelly-like sticky matrix having different types of cells and fibres and lot of mucin
...

1
...

2
...
g
...

Some of these can engulf bacteria and prevent infection
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These tissues are found between the skin and muscles, around blood vessels and nerves and in the bone marrow
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It gives support to various organs and acts as a packing material between various structures of the body
...

2
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3
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Adipose tissue
Nature: It is a modified form of connective tissue
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The matrix of adipose
tissue is packed with large, spherical or oval fat cells or adiposities
...

Occurrence: The adipose tissues are present beneath the skin, around kidneys and in mesentry and bone marrow
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It forms soft elastic pads between organs and parts
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2
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3
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4
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5
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Thus, it regulates the body temperature
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It is characterized by ordered and densely
packed collection of fibre & cells
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Tendons
It is a dense fibrous connective tissue with thick parallel bundles of collagen fibres (matrix)
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It connects muscles to hones
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The collagen fibres are
present in rows of fibroblast and are bounded by areolar connecting tissues
...
Its ground substance or matrix is densly crowded with yellow elastin
fibers branched in different directions
...
The ligaments
connect bones at the joints & hold them in position- thus, enable us to move & rotate our neck, limbs, fingers etc
...

It is a thick, tough and non-elastic
connective tissue
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It connects muscles to a bone
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It is formed of white fibrous tissues
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Fibres are white and formed of
collagen protein
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It connects two bones
...

Fibres are yellow and formed of protein
elastin
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It restricts or limits the movement of bones
...
It supports the body, protects vital organs and provides hard
surface for the insertion of muscles
...

Cartilage
Nature: It is solid but semi-rigid and flexible connective tissue
...
It is tough, transparent and homogeneous, formed of a special glycoprotein It is secreted by
cartilage cells or chondrocytes
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The cartilage is
bounded externally by white fibrous connective tissue perichondrium
...
The food and oxygen diffuse through matrix to reach the condrocytes
...


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Occurrence; Cartilage is found in nose tips, ear pinna, ring of trachea (wind-pipe), end of long bones,
lower ends of ribs, and epiglottis
...


Bone
Nature: Bone is a solid, rigid and strong connective tissue
...
The bone cells are called osteocvtes
These are stellate cells and each of them is enclosed in a small cavity, the lacunae
...
Fine processes of osteocytes extend through these conaliculi and are
connected with the processes of other osteocytes
...
It forms the framework that supports the body
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It protects vital body organs like brain, lungs, etc
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It anchors the muscles
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It provides shape to the body
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Bone is surrounded by a tough sheath, called
periosteum
...


Cartilage cells (choridroucytes) lie singly or
in groups of two or four
...


5
Chondrocytes
processes

are

oval and devoid of

Osteocytes are irregular and give off branching
processes

Fluid connective tissue
It is also called vascular tissue and is a special connective tissue that differs from atypical connective tissue in the
following respects:
1
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2
...

3
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Vascular tissue circulates in the body and helps in the transportation of materials from one part of the body
to other part
...

Types of vascular tissues
Vascular tissues are of two types: (a) Blood and (b) Lymph
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It is salty in taste and slightly alkaline in nature
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Blood is a complex transport medium
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It contains two components:
(1) Plasma and (2) Blood cells (corpuscles)

8

Plasma: It is a straw-coloured fluid, and makes up about 60% of the total blood volume or about 5
...
Plasma is a complex fluid and includes in it inorganic salts and organic compounds
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Blood cells : It is of three types:
1
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White Blood Cells (WBCs) or leucocytes
3
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The shape and size of RBCs vary in different animals
...
In almost all the vertebrates, except mammals, these are nucleated, oval
and biconvex
...
Actually, the nucleus is present in
the RBCs of mammals initially but when these cells are finally differentiated and mature the nucleus,
mitochondria and endoplasmic reticulum are degenerated
...

(ii) White Blood Cells (WBCs)
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All leucocytes are capable of amoeboid movement
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Phagocytes are capable of phagocytosis and they carry out the function of body defence by engulfing
bacteria and other foreign substances
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They include eosinophils, basophils and neutrophils
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They include monocytes
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Immonocytes: They produce antibodies and are involved in immune response
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(iii) Blood platelets or thrombocytes: These are minute, highly contractile, round or oval, biconvex discs with
granular cytoplasm, but without nucleus
...
They help in the clotting of blood in the
site of injury to a blood vessel, so as to prevent further loss of blood
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The highly branching network of vessels enables blood to reach every part of the body
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Blood is an important tissue since it performs many important functions in the body
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It transports oxygen from respiratory organs to various body tissues
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It carries carbon dioxide from body tissues to respiratory surfaces like lungs, skin, etc
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Digested food absorbed from the intestine is carried to different parts of the body
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It carries excretory wastes produced in the body to kidneys for elimination
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It maintains the body temperature
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Lymph is colourless since it has
no red blood corpuscles, but it contains more WBCs than the blood has
...


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Functions
1
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The WBCs of the lymph are the same as those of blood and have the same function of defense and of
assistance in tissue repair and healing
...
It brings carbon dioxide and nitrogenous wastes from tissue fluid to blood
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1

Red corpuscles present
...


Amount of nutrients and Oxygen comparatively
less
...


Amount of these wastes much more
...


White corpuscles more
...


Lymphocytes most numerous

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