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TISSUES OF THE BODY
Key Terms
• Histology:
• the study of tissues.
• Tissues:
• Cells which are similar in structure and which
perform common or related functions.
Four Basic Kinds of Tissues
•Epithelial Tissue
•Connective Tissue
•Muscle Tissue
•Nervous Tissue
Epithelial Tissue
• Epithelial Tissue Locations:
• Covers the body
• Lines the cavities, tubes, ducts and blood vessels inside the
body
• Covers the organs inside body cavities
• Functions:
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Protection from physical & chemical injury,
Protection against microbial invasion,
Contains receptors which respond to stimuli,
Filters, secretes & reabsorbs materials and
Secretes serous fluids to lubricate structures.
Connective Tissue
• Connective Tissue:
• Most abundant & widely distributed
tissue
• Functions:
• Connects, binds and supports structures,
• Tendons, ligaments, etc.
• Protects & cushions organs and tissues,
• Insulates (fat) and
• Transports substances (blood).
Muscle Tissue
• Muscle Tissue location:
• Associated with the bones of the skeleton, the heart and in
the walls of the hollow organs of the body.
• Functions:
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Movement
Locomotion
Maintains posture
Produces heat
Facial expressions
Pumps blood
Peristalsis( wave- like motion )
Nervous Tissue
• Nervous Tissue location:
• Main component of the nervous system,
ie., brain, spinal cord & nerves.
• Functions:
• Regulates & controls body functions
• Generates & transmits nerve impulses
• Supports, insulates and protects impulse generating neurons.
Different types of Epithelium
Squamous Epithelium
• Simple – one cell thick
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Stratified – multiple
layers
Forms epidermis
Cuboidal Epithelium
Cuboid Cells
• Simple – one cell thick
• Roughly cube shaped
Duct
Cuboid Cells
Duct
Columnar Epithelium
• Simple – one cell thick
• Column shaped (long &
narrow)
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Pseudostratified –
gives the appearance
of more than one layer
of columnar epithelial
cells
• THE CONNECTIVE TISSUES
• consist of a population of cells
surrounded by fibers and aground
substance. These tissues connect
and anchor structures and give
support to the body and its
organs.
• 1. Loose connective tissues
(adipose tissue)
• 2. Dense connective tissues
(tendon)
• 3. Support tissue (cartilage and
bone)
• 4. Blood and blood forming tissue
(red marrow)
Loose Connective - Adipose
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Stores energy (fat)
Insulates
Supports & protects
organs
Dense Connective- Tendon
• In tendon and ligament, fibers
are thick, long and grouped in
parallel assembly for tensile
strength.
Support tissue - Bone
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Supports & protects
Mineral storage
Fat storage
Blood cell production
Support tissue – Hyaline Cartilage
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Supports while
providing flexibility
Absorbs compression
between bones in
joints (articular
cartilage)
Holds open respiratory
passages
Most abundant type of
cartilage in body
Blood
• Blood is considered a
connective tissue because it
has a matrix.
• The fluid portion of whole
blood, its matrix, is called
plasma.
Muscle Tissue Types:
• Consists of specialized cells that contract when
stimulated
• The body has three types of muscle tissue:
• Skeletal (voluntary)
• Cardiac (involuntary)
• Smooth muscle (involuntary)
Muscle - Skeletal
• Muscle fibers (cells)
long, parallel &
cylindrical
• With many nuclei
(multinucleate)
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Striations (cross
stripes run
perpendicular to the
cells
Cardiac Muscle
• Cells, found only in the
heart, are striated and
branching (with one
nucleus);
• They are joined by
intercalacted discs
which allow the cells to
synchronize the
beating of the heart.
Smooth Muscle
• Lack of visible cross striations
(hence the name smooth).
• Nucleated
• Is responsible for the
contractility of hollow organs,
such as blood vessels, the
gastrointestinal tract, the
bladder, or the uterus.
Specific Nervous Tissue Types
Nervous – Neuron
• Conducting cells, called
neurons, transmit
impulses from one region
of the body to another.
Membranes
• Sheets of tissue that cover or
line surfaces or that separate
organs, or parts of organs from
one another.
• Mucous – line cavities or
passages -that open to the
exterior such as mouth,
esophagus, digestive tract,
respiratory passages
• Function in protection,
secretion of mucus, and
absorption
Cutaneous MembraneCovers the body
•Are continuous with
mucous membranes(skin)
Serous membrane
• Line closed cavities of
the body such as
thoracic, abdominal,
and sac in which heart
lies.
• Also cover organs lying
in those closed cavities
• Has two layers
• Visceral – covers organs
• Parietal – lines the
cavity
• Space between the two
layers is kept moist by
the secretion of serous
fluid.
Synovial
MembranesLine joints, tendons,
and bursa(A sac
containing synovial
fluid at sites of friction)
• Secrete synovial fluid
which prevents
friction on the
smooth, moist
surfaces