Tissue:-
·
It is the
organisation of similar cells which along with intracellular substances perform
specific functions, called tissue.
·
There are specialized type of junctions are present between the cells in all type of
tissues, which provide structural and functional link between cells in the
tissues.
·
Junctions
are of three types-
1) Tight
Junctions- To stop leaking of substances
across the tissues.
2) Adhering
Junctions- To keep the neighboring cells
together via cementing.
3) Gap
junction- To communicating each other
through cytoplasm and also help in rapid transfer of ions, small molecules and
big molecules.
·
In
multicellular animals, four type of tissues are present.
1.
Epithelial
tissue
2.
Connective
tissue
3.
Macular tissue
4.
Nervous
tissue
The
Epithelial tissue:-
- The tissue having free surface which present between body fluid and outer environment. The cells of this tissue are completely packed together with lattice intracellular spaces.
- It is also of two types.
1.
Simple epithelium
tissues
2.
Compound
epithelium tissue
1)
Simple
epithelium tissue:-
- It consists of single later of cells and present in the body cavities, ducts and tubes.
- On the basis of structure it also are of three types.
i.
Squamous
ii.
Cuboidal
iii.
Columnar
I.
Squamous:-
- It consist of single thin layer flattened cells with irregular boundary.
- They are mostly found in wall of blood vessels, air sac of lungs.
- It acts like s diffusion boundary.
II.
Cuboidal:-
- It consists of single layer of cube cell.
- It is found in ducts of glands and tubular part of nephron in kidney.
- It functions as absorption and secretion.
III.
Columnar:-
- It is a single layer of tall and cylindrical cells having nuclei at the base of cell.
- It is lining the stomach and intestine.
- It also helps in secretion and absorption.
Fig- Simple
Epithelium (a) Squamous, (b) Cuboidal, (c) Columnar, (d) Columnar cells bearing
cilia.
Ø Ciliated epithelial-
·
It consist
the ciliated columnar and Cuboidal cells.
·
It mainly
present in inner surface of hollow organs such as bronchioles and fallopian
tubes.
·
It functions
to move particles or mucus in specific direction.
Ø Glandular epithelium-
·
Some
cuboidal or columnar cells get specialised for secretion called glandular
epithelium.
·
It may be
unicellular globular cells (Goblet cells of alimentary canal) or multicellular
glandular epithelial cells
·
On the basis
of pouring it may be-
· Endocrine- It
is open through ducts and secretes mucus, saliva, earwax oils, milks, digestive
enzymes and other cell products
·
Exocrine- It
doesn’t have ducts i.e. it secrete the hormones directly into fluids.
Fig- Glandular Epithelium (a) Unicellular,
(b) Multicellular.
|
1)
Compound
Epithelum tissue:-
·
It consists of
more than one layer of cells.
·
It covers
the dry surface of skin, moist surface of buccal cavity, pharynx, inner surface
of ducts of salivary gland and pancreatic ducts.
·
Its main
function to provide protection against chemical and mechanical strength, only limited
role in absorption and secretion.
Fig-
Compound Epithelium
|
Connective
Tissue:-
·
It consists
of cartilage, bone, adipose and plasma. It is widely distributed in the whole
body.
·
Due to its
functions to form a linkage among each other, called connective tissue.
·
All the
cells of connective tissue except blood cell secretes fibres of structural
protein called collagen or elastin.
·
The fibres
functions to provide strength, elasticity, and flexibility to the tissues.
·
It is of
three types-
1.
Loose
connective tissue
2.
Dense
connective tissue
3.
Specialised
tissue
1)
Loose
Connective Tissue:-
·
It consists
of cells and fibres which are loosely arranged in a semi-fluid ground
substance. It also contains fibroblast, macrophage and mast cells.
·
It serves to
give support for the epithelium.
Examples:-
Areolar tissue (present beneath the
skin) &
Adipose Tissue- It also another type of
loose connective tissue which located just beneath the skin. Its cells contain
excess of fats (fat is excess of nutrients which not used by body for output
work)
Fig Loose Connective Tissue (a) Areolar Tissue,
(b) Adipose Tissue
|
2)
Dense
Connective tissues:-
·
It consists
of fibres and fibroblast which are compactly packed.
·
On the basis
of orientation of fibres, it is of two types-
1) Dense
Regular Connective Tissue: - In which
arrangement of fibres show regular pattern i.e. the collagen fibres are present
rows between many parallel bundles of fibres. Ex- tendon and ligament.
2) Dense
Irregular Connective Tissue:- In which
arrangement of fibres show irregular Pattern i.e. the fibres and fibroblast are
arranged in irregular pattern.
Fig- Dense Connective tissue (a) Dense
Regular, (b) Dense Irregular
|
3)
Specialised
Connective Tissue:-
·
It is
consists of Cartilage, Bones and Blood.
Ø Cartilage:-
·
It consists
of chondrocytes cells having solid and pliable intracellular material.
·
Its cells
are enclosed in small cavities within the matrix secreted by them.
Example-
1. It is present in vertebrate of embryo which
replaced into bones into adult.
2. It is also present in tip of nose, outer ear
joints, Between adjacent bones of the vertebral column, limbs and hand in
adult.
Ø Bones:-
·
It is consist
of osteocyte cells having hard and non- pliable ground substance.
·
Ground
Substances have calcium salts and collagen fibres which is responsible for its
strength.
·
Its main
function to give support and protection of Tissue and organ and also help in
movement at the region where skeleton muscles interact with it.
·
Bone marrow
in some bones is responsible for formation of blood cells.
Ø Blood:-
·
It is the
fluid connective tissue containing Red Blood Cells (RBC), White Blood Cells (WBC), Plasma and Platelets.
·
It is the
main circulatory system and responsible for transportation of various
substances.
Muscular
Tissue:-
·
It is
consists of many long, cylindrical fibres which is arranged parallel to each
other. Hare fibre made up of many fibrils called myofibrils.
·
Muscle
fibres are contracted (Shorten), when any response occurs and then relaxed
(lengthen) to their original state.
·
They play an
active role in movement of body.
·
Muscles are
of three types- Skeletal, Smooth and Cardiac.
1.
Skeletal
Muscle:-
·
It consists
of skeleton muscle fibres which arranged parallel to each other and they
enclose in a sheath connective tissue.
·
It is
closely attached to skeleton bones and present into the typical muscles like
the biceps.
2.
Smooth
Muscle:-
·
It consists
of smooth muscle fibres which are fusiform and held together by cell junctions
like bundles and enclosed in a sheath of connective tissue.
·
It is
present in walls of internal organ such as blood vessels, stomach and
intestine.
·
It can’t
directly controlled i.e. we can do this with skeleton muscles.\
3.
Cardiac
Muscle Fibres:-
·
It consists
of cardiac muscle cells and its cell junction fuse the plasma membrane to make
them sticky.
·
It is
present only in the heart having some junction at some points on the heart;
allow the cell to contract along with neighbour cells.]
Fig- Muscular Tissue (a) Skeletal, (b)
Smooth, (c) Cardiac
|
·
It consists
of nerve cells and nuwrogleal cells. The neural tissue controls the
responsiveness of whole body. Here the neuron is stimulated, and electric
disturbances is generated which travels with their plasma membrane.
·
Neuralgia
cells protect and support neurons. It makes more than one-half of the volume of
the neural tissue in the body.
Fig- Neural Tissue (Neurons with Neuralgia)
Organ and Organ System:-
·
The tissue constitute together to form organ and
organ associate to form organ system.
·
Heart is associated with all type of tissues.
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