Definition: Tissue may refer to a group of biological cells that perform a similar way to function.
Histology:
It is a branch of medical science which deal with the study of tissue.
Types
of Tissue
1.
Epithelium
Tissue:
·
(EpI-Upon Thelium-membrane)
·
This tissue grows upon a basement
membrane.
· Epithelial layers contain no blood
vessels, so they must receive nourishment via diffusion of substances from the
underlying connective tissue, through the basement membrane.
Classification of Epithelium Tissue:
A.
Based
on number of layers:
·
Simple
Epithelium: It is a single layered or one cell thick.
Every cell in direct contact with the underlying basement membrane
·
Stratified
Epithelium: It is multi-layered.
B.
Morphology
of their cells:
·
Squamous epithelium (flat and scale like
cells)
·
Cuboidal epithelium (Cube-shaped cells)
·
Columnar epithelium (Column-Shaped cells)
Epithelium tissue is
present in outer layer of skin, inner lining of mouth, digestive tract,
visceral organ, blood vessels and glands.
Functions
of Epithelium Tissue
·
This tissue is responsible for absorption
of water & nutrient, elimination of waste, secretion of enzymes, hormones
and protection.
2.
Connective
Tissue: Connective tissue that connects supports, bind or
separates other tissues or organs. All connective tissue consists of three main
components:
·
The cells of connective tissue include
fibroblast, adipocytes, macrophages, mast cells etc.
·
The fibers: elastic, collagenous fibers.
·
The ground substances (matrix)
Types
of Connective tissue:
There are three types of
connective tissue:
a)
Fibrous
connective tissue: e.g. Adipose tissue, Areolar tissue
· Ligaments:
the fibrous connective tissue which joint bone
to bone strongest ligaments of human body is illio femoral ligament which joint hip joint (ilium) to femur in front
of the joint.
· Tendon:
The fibrous connective tissue which joint bone
to muscle. Strongest tendon of human body is Achilles tendon of heal cord or calcaneal tendon, situated
at back of the leg, which joint the heal bone to calf muscle.
b)
Skeletal
connective tissue: It include bone and cartilage
· Osteoblast: bone
forming cell.
· Osteoclast:
bone destructing or shaping cell.
· Chondroblast:
cartilage forming cell.
v The
fibrous connective tissue and skeletal connective tissue provide the mechanical support to human body.
c)
Fluid
connective tissue:
· It
includes blood, plasma and lymph.
· The
matrix of fluid connective tissue is in liquid state.
3.
Muscular
Tissue: muscular tissue is soft tissue that composes muscle
and gives rise to muscle ability to contract.
· Myocyte:
Muscle forming cell.
· Myogenesis:
The process of muscle formation.
Types
of Muscular tissue:
There are three types of muscle in human body:
a)
Skeletal
muscle: they are striated in structure and under voluntary
control is situated in association with skeletal muscle are multinucleated
usually. The skeletal muscles form 40
to 50% of body mass.
· Sarcomere:
it is defining as the structural and functional unit of skeletal muscle. It is
also called the basic contractile
unit of muscle.
· Functions:
they carry out movement of the body, maintain the posture of the body and
support the body.
b)
Smooth
muscle: Smooth muscle is situated in association with
visceral, it is also called visceral muscle. They are Non-striated and Involuntary
in nature.
· Function:
they are responsible for the contractility of hollow organs, such as blood
vessels, GI Tract, bladder etc.
c)
Cardiac
Muscle: They forms the musculature (myocardium) of the heart. These muscles are striated and Involuntary
in nature.
· Function:
cardiac muscles are the self –contacting, automatically regulated and must
continue to contract in rhythmic fashion for the whole life of the human.
4.
Nervous
Tissue: Nervous tissue consists of Neurons and supporting
cells.
· Neuron
or nerve cell is defined as the structural and functional unit of nervous
system.
· Neuron
is similar to any other cell in the body having nucleus and all the organelles
in cytoplasm, however, it is different from other cell by two ways:
i.
Neuron has branches or processes
called Axon and Dendrites.
ii.
Neuron does not have centrosome, so it cannot undergo
division that’s why have minimum power or regeneration.
Types
of Nervous tissue:
On the basis of function, nerve cells are classified
in to two types:
a)
Sensory
or afferent Neurons: They carry the sensory impulses from
periphery to CNS.
b)
Motor
or Efferent neurons: They carry the motor impulses from CNS to
periphery.
v Synapse:
The junction by which the neurons communicate with each other.
Anatomy and Physiology Quiz Series
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