The Tissue
Prof. Amol B. Deore
Department of Physiology
MVPS Institute of Pharmaceutical Sciences,
Nashik

Tissue
•A group of cells similar in form, structure and
embryonic origin which coordinate to perform
a specific function is called a simple tissue.
•Various tissues combine together in an
orderly manner to form large functional units
called organs.
•Number of organs work in coordination and
give rise to organ-system.

A tissue is a group of similar cells which are specialized
for a particular function.
The branch of science that deals with the microscopic
study of tissues is called histology.

•Epithelial tissue: (Covering tissues. These
tissues are present for protection)
•Connective tissue: (Supporting tissues. These
tissues help in binding different body Structures)
•Muscular tissue: (Contractile tissues. These
tissues help in movements and locomotion)
•Nervous tissue: Conducting tissues. These
tissues help in conduction of nerve impulses.)
The fundamental types of body tissues

Epithelial tissue
•General position: It covers the outer
surface of all the organs of the body and
also lines the cavities of all the hollow
organs of the body.
•Structure: Epithelium consists of closely
packed cells arranged in continuous
sheets, in either single or multiple layers.

The attachment between the epithelium and the
connective tissue is a thin layer called the basement
membrane.
Epithelial tissue can be named according to shape,
arrangement, or function.

Functions of epithelial tissue
•Epithelial tissue functions in four ways:
•It protects underlying tissues; it absorbs
nutrients; it secretes hormones, mucus, and
enzymes; and it excretes waste material like
urea in sweat

•Simple Epithelium
•It consists of single layer of cells.
•Stratified Epithelium
•Stratified epithelium has two or more
layers of cells. Because of this, it is more
durable and can better protect underlying
tissues.
Classification of Epithelium

Epithelial tissue is classified as follows
• Simple epithelium
• Simple squamous epithelium
• Simple cuboidal epithelium
• Simple columnar epithelium
• Pseudostratified columnar epithelium
• Stratified epithelium
• Stratified squamous epithelium
• Stratified cuboidal epithelium
• Stratified columnar epithelium
• Transitional epithelium

SIMPLE EPITHELIUM
•It consists of single layer of cells. It is
further divided in four types as follows.

Simple Squamous Epithelium
•This tissue made up of a single layer
of flat cells. The nucleus of each cell is
oval and is located centrally.
•Location: skin, the heart, blood
vessels and lymphatic vessels, body
cavities, and alveoli (air sacs) of
lungs.
Functions
•They act as outer layer skin to protect
the body against microbial attack.
•Filtration of blood in the kidneys.
•Diffusion of gases like oxygen and
carbon dioxide in lungs.
Basement membrane

Simple Cuboidal Epithelium
•This tissue made up of cube-shaped
cells.
•The nucleus are usually rounded
and centrally located.
•Location: the thyroid gland and
kidneys tubules, retina, ovaries and
secretary parts of certain glands.
Functions
•Absorption, secretion and
protection.

Simple Columnar Epithelium
• The cells of simple columnar epithelium appear
like columns, with oval nuclei near the base.
• They found in the ducts, digestive tract
(especially the intestinal and stomach lining),
parts of the respiratory tract, reproductive
system and glands.
• Non-ciliated simple columnar epithelium
• Ciliated simple columnar epithelium.
Functions
• Secretion of mucus as a lubricant for the linings
of the digestive, respiratory, and reproductive
tracts, and the urinary tract.
• Cilia also help move oocytes expelled from the
ovaries through the fallopian tubes into the
uterus.

Pseudostratified Columnar Epithelium
• It is made up of several layers columnar epithelium
but the nuclei are located at various depths.
• Even though all the cells are attached to the
basement membrane in a single layer, some cells do
not extend to the superficial surface.
Locations
• The linings of throat, trachea, and bronchi of the
lungs consist of mucous glands which secrete mucus
which traps foreign particles and the cilia sweep
away mucus for elimination from the body.
Functions
• Lubricant and provide protection

STRATIFIED EPITHELIUM
•Stratified epithelium has two or more
layers of cells.
•Because of this, it is more durable and
can better protect underlying tissues.

Stratified Squamous Epithelium
•It is made up of several layers of
polyhedral cells.
•It is found in our mouth cavity, skin,
esophagus and vagina
Functions
•Protection of skin from the harmful
rays of the sun and certain chemicals.
•Protection of underlying tissue from
scratch as food moves through the
tract.

Stratified Cuboidal Epithelium
•This is a fairly rare type of epithelium
in which cells in the superficial layer
are cuboidal.
•It is found in sweat glands, salivary
glands and mammary glands
Functions
•Secretion
•Sweat glands excrete waste products
such as urea.
•Salivary gland secretes saliva
•Mammary gland secretes milk

Stratified columnar epithelium
•Usually the basal layers consist of
irregular shaped cells; only the
superficial layer has cells are
columnar in shape.
•It is found in male urethra and ducts
of certain glands
Functions
•Protection and secretion

Stratified Transitional Epithelium
•It is made up of several layers of closely
packed, polyhedral, flexible, & easily
stretched cells.
•It is present only in the urinary system (the
ureters, the urinary bladder, and the upper
part of the urethra).
Functions
•Contraction and relaxation: it permits
expansion of urinary bladder because of its
elasticity.
•It allows the urinary bladder to stretch to
hold urine without rupturing.

CONNECTIVE TISSUE
•Most abundant and widely distributed tissues in
the body.
•Functions:
•It binds together, supports, and strengthens
other body tissues;
•protects and insulates internal organs; serves
as the major transport system within the body
(blood).

Connective tissue consists of ground substance and fibers; matrix with few
cells.
It is highly vascular tissue with nerve supply.
Connective tissues are comprised of different cells like
•fibroblast,
•macrophages,
•plasma cells,
•mast cells,
•adipocytes, and
•white blood cells.
Matrix contains collagen fibers, elastic fibers and reticular fibers.

•Areolar Connective tissue
•Adipose Tissue
•Fibrous Connective tissue
•Hyaline Cartilage
•Fibrocartilage
•Elastic Cartilage
•Bone (Osseous) Tissue
•Blood
Classification of connective tissue

Areolar Connective tissue
•It contains several types of cells, including fibers (collagen,
elastic, and reticular) and several kinds of cells (fibroblasts,
plasma cells, macrophages, adipocytes, and mast cells)
embedded in a semifluid matrix.
•It is found in subcutaneous layer of the skin; and around
blood vessels, nerves, and body organs.
Functions
•Supports both nerve cells and blood vessels.
•It provides strength and elasticity.
•Areolar tissue also (temporarily) stores glucose, salts, and
water.

Adipose Tissue
•Adipose tissue contains adipocytes; with peripheral
nucleus.
•They are specialized for the storage of fats and
triglycerides.
Location
•Adipose cells are found throughout the body: in the skin
layer, around the kidneys, behind the eye socket, within
padding around joints, and in the yellow bone marrow.

Functions
• Adipose tissue is a good insulator and can therefore reduce heat loss through the
skin, act as an energy reserve.
• It is a major energy reserve and generally supports and protects various organs.
• This tissue stores fat.
• It acts as protective material tissue, cushions, supports, and protect the body.

Fibrous Connective tissue
•It is made up of closely packed white collagen fibers. Collagen
fibers arranged in bundles.
•Fibrous tissue is flexible, but not elastic. This tissue forms
ligaments (attach bone to bone) and tendons (attach skeletal
muscle to bone).
Functions
•Ligaments are strong, flexible bands which hold bones firmly
together at the joints.
•Tendons are white, shiny bands attaching skeletal muscles to
the bones.

Hyaline Cartilage
•It consists of a strong gel and chondrocytes.
•Hyaline cartilage is found on the ends of long bone
surfaces, ribs, larynx, trachea, bronchi and bronchial
tubes.
Functions
•It provides movement of joints, flexibility and support.
•The hyaline cartilage that attaches the upper seven
pair of ribs to the sternum.

Fibrocartilage
•It consists of chondrocytes and bundles of collagen
fibers within the matrix.
•It is located within intervertebral discs and pubic
symphysis between the pubic bones.
Functions
•It is a strong, flexible, supportive substance, found
between bones and wherever great strength (and a
degree of rigidity) is needed.

Elastic Cartilage
• In this tissue, chondrocytes are
located in thread like network of
elastic fibers within the matrix.
• It is located inside the auditory
ear tube, external ear, epiglottis,
and larynx.
Functions
• Give support and maintains
shape

Bone (Osseous) Tissue
•Bone tissue contains intercellular matrix which is
calcified by the deposition of mineral salts (like calcium
carbonate & Calcium phosphate).
•Calcification of bone gives strength. The entire
skeleton is composed of bone tissue.
Functions
•The skeleton of the body made up of bones which
support and protect underlying soft tissue parts and
organs.
•It serves as attachments for skeletal muscles.

Blood
• Blood is a fluid connective tissue made up of blood cells
and plasma.
• Plasma consists of water with variety of dissolved
substances like nutrients, wastes, enzymes, plasma
proteins, hormones, respiratory gases, and ions.
• The blood cells are three types:
• Red blood cells, (Erythrocytes)
• White blood cells (Leukocytes) &
• Platelets (Thrombocytes)

Functions
• Erythrocytes transport oxygen and carbon dioxide.
• Leukocytes promote phagocytosis of foreign microbes and
involved in allergic reactions and immunity.
• Thrombocytes are essential for the blood clotting.

MUSCLE TISSUE
•Muscle tissue consists of fibers to generate force of
contraction.
•As a result, muscular tissue produces body
movements, maintains posture, and generates
heat.
•Based on location and certain structural and
functional characteristics, muscle tissue is
classified in to three types:
•Smooth, Skeletal and Cardiac muscle.

Smooth Muscle
• Smooth muscle is non-striated because it does not contain striations
(bands) of skeletal muscles.
• Smooth muscle cells are single nucleated and spindle-shaped.
• Its movement is involuntary.
• It makes up the walls of the blood vessels, eye pupil, the stomach
intestine, gallbladder, urinary bladder, and reproductive tract, airways of
lungs, and lymphatic vessels.
Functions
• These provide for involuntary movement.
• Examples include the movement of materials along the digestive tract,
controlling the diameter of blood vessels and the pupil of the eyes.

Cardiac Muscle
•It is striated (having a cross-banding pattern), involuntary (not
under conscious control) muscle.
•It makes up the walls of the heart.
•Cardiac muscle fibers are branched containing a single nucleus
that is located centrally.
•Cardiac muscle fibers are attached to each other by intercalated
discs, which contain gap junctions and desmosomes.
•Gap junctions provide a route for quick conduction of action
potential of muscle throughout the heart.

Functions
•Cardiac muscle contraction pumps the blood
though the heart into systemic circulation

Skeletal Muscle
•It is striated. The muscle fibers contain altering light and dark
bands. The skeletal muscle is voluntary, because it is under
conscious control.
•Skeletal muscles are attached to the skeleton (bones, tendons
and other muscles).
Functions
•These muscles are attached to the movable parts of the skeleton.
•They are capable of rapid, powerful contractions which allow
voluntary movement.

NERVOUS TISSUE
•The nervous system consists of only two
principal types of cells: neurons and neuroglia.
•Neurons (or nerve cells) are sensitive to various
stimuli.
•They convert stimuli into electrical signals
called nerve impulses and conduct these
impulses to other neurons, to muscle tissue, or
to glands.

Neuroglia cells are nerve cells that support
and protect the neurons.
Nerve cells (neurons) are the working units
of the nervous system that generate and
transmit nerve impulses.

Neuron
• Neurons consist of three elementary parts: a cell body,
dendrites and axons.
• The cell body contains the nucleus and other organelles.
• Dendrites are highly branched and usually short cell
extensions. They are the major input portion of a
neuron.
• The axon of a neuron is a single, thin, cylindrical process
that may be very long.
• It is the output portion of a neuron, conducting nerve
impulses toward another neuron.

Neuroglia
•Neuroglia’s do not generate or conduct
nerve impulses, these cells do have
many significant supportive functions.

Summary

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