This document provides an overview of the four main types of tissues in the body: epithelial, connective, muscular, and nervous tissue. It describes the characteristics and functions of each tissue type. For epithelial tissue, it outlines the different categories (simple, stratified, transitional etc.) and provides examples. For connective tissue, it discusses the ground substance, fibers and cells. It also describes the different types of connective tissues (areolar, adipose, cartilage etc.). The document concludes with brief descriptions of muscular tissue (skeletal, cardiac and smooth muscle) and membranes that cover the body.

1. JIJI.V

3.  Tissues
 Tissue is a structure and that function
together as a unit.
 group of cells that have similar
 Primary types of body tissues include
 Epithelial,
 Connective,
 Muscular, and
 Nervous tissues.

4.  Body membranes are thin sheets of
tissue that cover the body, line body
cavities, and cover organs within the
cavities in hollow organs.
 Two main categories of body membranes
are epithelial and connective tissue
membranes. Sub-categories include
mucous membranes, serous membranes,
synovial membranes, and meninges.

5. Tissues
 Tissues are groups of similar cells
that have a common function.
 The four basic tissue types are
 Epithelial
 Muscle
 Connective, and
 Nervous tissue.

6. Epithelial
tissues
Connective
tissues
Muscle tissue Nervous tissue
Form the
covering of all
body surfaces,
line body
cavities and
hollow organs,
and are the
major tissue in
glands.
Bind
structures
together, form
a framework
and support
for organs and
the body as a
whole, store
fat, transport
substances,
protect against
disease, and
help repair
tissue damage.
Composed of
cells that have
the special
ability to
shorten or
contract in
order to
produce
movement of
body parts.
Responsible
for
coordinating
and controlling
many body
activities.

7. Each tissue type has a
characteristic role in the body
1. Epithelium covers the body surface
and lines body cavities.
2. Muscle provides movement.
3. Connective tissue supports and
protects body organs.
4. Nervous tissue provides a means of
rapid internal communication by
transmitting electrical impulses.

8. 1. Epithelium:
A membranous tissue composed of
one or more layers of cells that form
the covering of most internal and
external surfaces of the body and its
organs.

9.  The cells in epithelial tissue are tightly
packed together with very little
intercellular matrix.
 Because the tissues form coverings and
linings, the cells have one free surface that
is not in contact with other cells. Opposite
the free surface, the cells are attached to
underlying connective tissue by a non-
cellular basement membrane
 This membrane is a mixture
of carbohydrates and proteins secreted by
the epithelial and connective tissue cells.

10.  Types of Epithelial Tissue
 Epithelial tissues are identified by both
the number of layers and the shape of
the cells in the upper layers.
 There are eight basic types of
epithelium: six of them are identified
based on both the number of cells and
their shape;
 Two of them are named by the type of
cell (squamous) found in them.

11.  I .Simple Epithelia
 Simple epithelium consists of a single layer of cells.
They are typically where absorption, secretion and
filtration occur.
 Simple epithelial tissues are generally classified by the
shape of their cells.
 The four major classes of simple epithelium are:
1]Simple squamous;
2) Simple cuboidal;
3) Simple columnar; and
4) Pseudostratified.

13.  Simple Squamous
 Simple squamous epithelium cells are flat
in shape and arranged in a single layer.
This epithelial type is found in the walls of
capillaries, linings of the pericardium, and
the linings of the alveoli of the lung

14.  Simple Cuboidal
1. Single layer cells that are as tall as they are wide.
2. The important functions of the simple cuboidal
epithelium are secretion and absorption.
3. This epithelial type is found in the small collecting
ducts of the kidneys, pancreas, and salivary glands.

15.  Simple Columnar
 Single row of tall, closely packed cells,
aligned in a row.
 These cells are found in areas with high
secretory function (such as the wall of the
stomach), or absorptive areas (as in small
intestine ).
 They possess cellular extensions (e.g.,
microvilli in the small intestine, or the cilia
found almost exclusively in the female
reproductive tract).

16.  Pseudostratified
 Nuclei appear at different heights, giving the
misleading (hence pseudo) impression that the
epithelium is stratified when the cells are viewed in
cross section.
 Pseudostratified epithelium can also possess fine
hair-like extensions of their apical (luminal) membrane
called cilia. In this case, the epithelium is described as
ciliated pseudostratified epithelium.
 Ciliated epithelium is found in the airways (nose,
bronchi), but is also found in the uterus and fallopian
tubes of females, where the cilia propel the ovum to
the uterus.

17. II.Stratified Epithelium
 Multilayered. It is therefore found where
body linings have to withstand
mechanical or chemical insults.
 Stratified epithelia are more durable and
protection is one their major functions.
 Stratified epithelia can be columnar,
cuboidal, or squamous type.

18.  III.Keratinized Epithelia
 In keratinized epithelia, the most apical layers
(exterior) of cells are dead and lose their nucleus and
cytoplasm.
 They contain a tough, resistant protein called keratin.
This specialization makes the epithelium waterproof,
and it is abundant in mammalian skin.
 The lining of the esophagus is an example of a non-
keratinized or moist stratified epithelium.

19. IV.Transitional Epithelia
 Transitional epithelia are found in
tissues that stretch and it can appear
to be stratified, or stratified
squamous when the organ is
distended and the tissue stretches.
 It is sometimes called the urothelium
since it is almost exclusively found in
the bladder, ureters, and urethra.

20.  Connective tissue
 connective tissues bind structures together, form
a framework and support for organs and the
body as a whole, store fat, transport substances,
protect against disease, and help
repair tissue damage.
 They occur throughout the body.
 Connective tissues are characterized by an
abundance of intercellular matrix with relatively
few cells.
 Connective tissue cells are able to reproduce
but not as rapidly as epithelial cells. Most
connective tissues have a good blood supply but
some do not.

21. Connective tissue
 Numerous cell types are found in connective
tissue.
 Three of the most common are
the fibroblast, macrophage, and mast cell.
 The types of connective tissue include loose
connective tissue, adipose tissue,
dense fibrous connective tissue, elastic
connective tissue, cartilage, osseous tissue
(bone), and blood.


23.  Structure of Connective Tissue
 Connective tissue has three main
components:
1. Ground substance
2. Fibers
3. Cells
 Together the ground substance and fibers
make up the extracellular matrix.

24.  Connective tissue fibers provide
support. Three types of fibers are
found in connective tissue:
 Collagen
 Elastic fibers
 Reticular fibers

25.  Collagen: Collagen fibers are the strongest and most abundant of all
the connective tissue fibers.
 Collagen fibers are fibrous proteins and are secreted into the
extracellular space and they provide high tensile strength to the
matrix.
 Elastic Fibers
 Elastic fibers are long, thin fibers that form branching network in the
extracellular matrix. They help the connective tissue to stretch and
recoil.
 Reticular Fibers
 Reticular fibers are short, fine collagenous fibers that can branch
extensively to form a delicate network.

26.  Function of Connective Tissue
 Binding and supporting.
 Protecting.
 Insulating.
 Storing reserve fuel.
 Transporting substances within the
body.

27.  Connective tissue is divided into four
main categories:
 Connective proper
 Cartilage
 Bone
 Blood

28.  Connective tissue proper has two
subclasses: Loose and dense.
 Loose connective tissue is divided
into 1) areolar, 2) adipose, 3)
reticular.
 Dense connective tissue is divided
into 1) dense regular, 2) dense
irregular, 3) elastic.

29.  Areolar Connective Tissue
 These tissues are widely distributed and
serve as a universal packing material
between other tissues.
 The functions of areolar connective tissue
include the support and binding of other
tissues.
 It also helps in defending against infection.
When a body region is inflamed, the
areolar tissue in the area soaks up the
excess fluid as a sponge and the affected
area swells and becomes puffy, a condition
called edema.

30.  Adipose Tissue or Body Fat
 Adipose tissue: Yellow adipose tissue in paraffin
section with lipids washed out.
 This is loose connective tissue composed of
adipocytes.
 It is technically composed of roughly only 80% fat. Its
main role is to store energy in the form of lipids,
although it also cushions and insulates the body.
 The two types of adipose tissue are white adipose
tissue (WAT) and brown adipose tissue (BAT).
 Adipose tissue is found in specific locations, referred
to as adipose depots.

31.  Reticular Connective Tissue
 This tissue resembles areolar
connective tissue, but the only fibers in
its matrix are the reticular fibers, which
form a delicate network. The reticular
tissue is limited to certain sites in the
body, such as internal frameworks that
can support lymph nodes, spleen, and
bone marrow.

32.  Dense Regular Connective Tissue
 This consists of closely packed
bundles of collagen fibers running in
the same direction.
 This tissue forms the fascia, which is
a fibrous membrane that wraps
around the muscles, blood vessels,
and nerves.

33.  Dense Irregular Tissue
 This has the same structural elements
as dense regular tissue, but the bundles
of collagen fibers are much thicker and
arranged irregularly.
 It is part of the skin dermis area and in
the joint capsules of the limbs.

34.  Elastic Connective Tissue
 The main fibers that form this tissue are
elastic in nature. These fibers allow the
tissues to recoil after stretching. This is
especially seen in the arterial blood
vessels and walls of the bronchial tubes.

35.  VI .Cartilage
 This is a flexible connective tissue found in many areas in the bodies ,
including the joints between bones, the rib cage, the ear, the nose, the elbow,
the knee, the ankle, the bronchial tubes, and the intervertebral discs.
 Cartilage is composed of specialized cells called chondroblasts and, unlike
other connective tissues, cartilage does not contain blood vessels.
 Cartilage is classified in three types:
 1) Elastic cartilage,
 2) Hyaline cartilage, and
 3) Fibrocartilage, which differ in the relative amounts of these
three main components.

36.  1)Elastic Cartilage
 This is similar to hyaline cartilage but
is more elastic in nature. Its function
is to maintain the shape of the
structure while allowing flexibility. It
is found in the external ear (known as
an auricle) and in the epiglottis.

37.  2) Hyaline Cartilage
 This is is the most abundant of all cartilage in
the body.
 Its matrix appears transparent or glassy when
viewed under a microscope.
 It provides strong support while providing pads
for shock absorption.
 It is a major part of the embryonic skeleton, the
costal cartilages of the ribs, and the cartilage of
the nose, trachea, and larynx.

38. 3)Fibrocartilage
 This is a blend of hyaline cartilage
and dense regular connective tissue.
Because it is compressible and
resists tension well, fibrocartilage is
found where strong support and the
ability to withstand heavy pressure
are required. It is found in the
intervertebral discs of the bony
vertebrae and knee meniscus.

39.  VII.Blood
 This is considered a specialized form of
connective tissue.
 Blood is a bodily fluid that delivers
necessary substances, such as nutrients
and oxygen, to the cells and transports
metabolic waste products away from those
same cells.
 It is an atypical connective tissue since it
does not bind, connect, or network with any
body cells. It is made up of blood cells and
is surrounded by a nonliving fluid called
plasma.

40.  Nervous tissue is found in
the brain, spinal cord, and nerves. It is
responsible for coordinating and controlling
many body activities.
 It stimulates muscle contraction, creates
an awareness of the environment, and
plays a major role in emotions, memory,
and reasoning.
 To do all these things, cells in nervous
tissue need to be able to communicate with
each other by way of
electrical nerve impulses.

41.  The cells in nervous tissue that generate
and conduct impulses are
called neurons or nerve cells.

 These cells have three principal parts:
the dendrites, the cell body, and one axon.
The main part of the cell, the part that
carries on the general functions, is the cell
body.
 Dendrites are extensions, or processes, of
the cytoplasm that carry impulses to the
cell body. An extension or process called
an axon carries impulses away from the
cell body.

42.  Nervous tissue also includes cells that
do not transmit impulses, but instead
support the activities of the neurons.
These are the glial cells (neuroglial
cells), together termed the neuroglia.
Supporting, or glia, cells bind neurons
together and insulate the neurons.
 Some are phagocytic and protect
against bacterial invasion, while others
provide nutrients by
binding blood vessels to the neurons.

44.  Muscle tissue is composed of cells that have the special
ability to shorten or contract in order to produce
movement of the body parts.
 The tissue is highly cellular and is well supplied
with blood vessels.
 The cells are long and slender so they are sometimes
called muscle fibers, and these are usually arranged in
bundles or layers that are surrounded by connective
tissue.
 Actin and myosin are contractile proteins in muscle
tissue.
 Muscle tissue can be categorized into skeletal
muscle tissue, smooth muscle tissue, and cardiac
muscle tissue.

45.  Skeletal Muscle
 Skeletal muscle mainly attaches to the
skeletal system via tendons to maintain
posture and control movement for example
contraction of the biceps muscle, attached
to the scapula and radius, will raise the
forearm.
 Skeletal muscle fibers are cylindrical,
multinucleated, striated, and under voluntary
control.

46.  Cardiac Muscle Tissue
 Cardiac muscle has branching fibers,
one nucleus per cell, striations,
and intercalated disks. Its contraction is
not under voluntary control.
 Cardiac muscle tissue is found only in
the heart where cardiac contractions
pump blood throughout the body and
maintain blood pressure.

47. Smooth Muscle Tissue
 Smooth muscle cells are spindle shaped, have a
single, centrally located nucleus, and lack
striations. They are called involuntary muscles.
 Smooth muscle tissue is found associated with
numerous other organs and tissue systems such
as the digestive system or respiratory system.
 It plays an important role in the regulation of flow
in such tissues for example aiding the movement
of food through the digestive system via
peristalsis.

48.  Body Membranes

49.  Body membranes are thin sheets
of tissue that cover the body, line body
cavities, and cover organs within the
cavities in hollow organs.
 They can be categorized into
 Epithelial and connective
tissue membrane.

50.  Epithelial Membranes
 Epithelial membranes consist
of epithelial tissue and the connective
tissue to which it is attached.
 The two main types of epithelial
membranes are the mucous membranes
and serous membranes.

51.  Epithelial membrane
 Mucous membrane Serousmembrane
Connective tissue
 Synovial Meninges

52.  Mucous Membranes
 Mucous membranes are epithelial
membranes that consist of epithelial
tissue that is attached to an underlying
loose connective tissue.
 These membranes, sometimes
called mucosae, line the body cavities
that open to the outside.
 The entire digestive tract is lined with
mucous membranes. Other examples
include the respiratory, excretory, and
reproductive tracts.

53.  Most mucosal membranes contain
stratified squamous or simple columnar
epithelial tissue types.
 The submucosa is the tissue that connects
the mucosa to the muscle outside the tube,
 Submucosal exocrine glands secrete
mucus to facilitate the movement of
particles along the body’s various tubes,
such as the throat and the intestines.

54.  Serous Membranes
 Serous membranes line body cavities that do not open
directly to the outside, and they cover the organs
located in those cavities.
 Serous membranes are covered by a thin layer of serous
fluid that is secreted by the epithelium.
 Serous fluid lubricates the membrane and reduces
friction and abrasion when organs in the thoracic
or abdominopelvic cavity move against each other or
the cavity wall.
 Serous membranes have special names given according
to their location. For example, the serous membrane that
lines the thoracic cavity and covers the lungs is
called pleura.

55.  Connective Tissue Membranes
 Connective tissue membranes contain
only connective tissue.
 1.Synovial membranes and
 2.Meninges belong to this category.

56. 1.Synovial Membranes
 Synovial membranes are connective tissue
membranes that line the cavities of the
freely movable joints such as the shoulder,
elbow, and knee.
 Like serous membranes, they line cavities
that do not open to the outside..
 Synovial membranes secrete synovial
fluid into the joint cavity, and this lubricates
the cartilage on the ends of the bones so
that they can move freely and without
friction.

58. 2. Meninges
 The connective tissue covering on
the brain and spinal cord, within
the dorsal cavity, are called meninges.
They provide protection for these vital
structures.

59.  Meninges
 The meninges is the system of
membranes that envelopes the central
nervous system. The meninges consist
of three layers: the dura mater, the
arachnoid mater, and the pia mater.
 The primary function of the meninges
and of the cerebrospinal fluid is to
protect the central nervous system.