Tissues
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Introduction
• Cells become specialized to perform specific functions
– Tissues are: groups of similar cells that perform the same
function
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Tissues differ from each other in:
1. size,
2. shape
3. arrangement,
4. function
4 TISSUE TYPES
Four primary tissue types
• 1. Epithelial tissue
• 2. Connective tissue
• 3. Muscle tissue
• 4. Nervous tissue
EPITHELIAL TISSUE
• Sheets of cells covering body surfaces or lining
body cavities or structures that secrete
substances
• Found in:
– Epidermis of skin (stratified squamous)
– Lines digestive tract (stomach-rectum=simple
columnar)
– Walls of blood vessels (alveoli of lungs=simple
sqaumous)
– Inner lining of body cavities/organs/glands (sweat
gland and kidneys=simple cuboidal)
Epithelial Structure: #
layers
a. Simple epithelium
– Single cell layer
– Flat, irregular shape
b. Stratified Epithelium
– Two or more cell
layers
Common in high-abrasion
areas
– e.g., Skin surface, mouth
Epithelial Structure: Cell
Shape
Cell shape
• All epithelia have six sides
• Cells vary in height
• Three common shapes
– Squamous cells
– Cuboidal cells
– Columnar cells
– Shape of nucleus conforms to
shape of cell
Muscle Tissue
1. Muscle tissue is contractile tissue
2.Provide us with motion, posture and heat
3. Muscle cell or fiber is basic unit
4. 40-50% of body weight
5. 3 Types of muscle
A. skeletal muscle
B.cardiac muscle
C.smooth muscle
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Skeletal Muscle Tissue
A. Covers skeleton-attached to bone
B. Visible light and dark banding (looks
striated) so it is called striated muscle
C. Voluntary or conscious control
D.Cells are long cylinders with many nuclei
E. Muscle fibers contract and relax rapidly
when stimulated
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Skeletal Muscle
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Cardiac Muscle Tissue
1. Appearance: cells are slightly striated
branched cylinders with one central nuclei,
cells interlace
2. Fx: attached to and communicate with
each other by intercalated discs
3. Contracts involuntarily
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Cardiac Muscle
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Smooth Muscle Tissue
1. Appearance:Spindle shaped cells with a
single central nuclei
2. Location: Walls of hollow organs (blood
vessels, GI tract, bladder)
3. Involuntary and nonstriated
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Smooth Muscle
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Connective Tissue -7
types
1. Loose connective tissue
2. Elastic connective tissue
3. Adipose
4. Fibrous
5. Cartilage
6. Bone
7. Blood
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Characteristics of Connective
Tissues
A. Cells far apart with a lot of intercellular
material
B. Intercellular material is secreted out to
produce the Matrix (fibers & substances
secreted by cells
C. Matrix varies from liquid, gel to solid
D. Has good nerve & blood supply except
cartilage & tendons
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Types of cells in Connective
1. Fibroblasts= most numerous, star-shaped.
-Produce collagenous and elastic fibers found in matrix.
2. Macrophages= less numerous
– engulf bacteria & debris by phagocytosis
*NO FREE SIDE ON CONNECTIVE: IT IS SURROUNDED BY
OTHER TISSUE OR ORGANS
*NO BASEMENT MEMBRANE (ONLY ON EPITHELIAL)
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Types of Fibers in Connective Tissue
1. Collagenous (25% of protein in your body)
A.tough, resistant to pull, yet pliable
B. formed from the protein collagen
C. White in appearance, abundant in tendons
2. Elastic (composed of elastin)
A.Very elastic
B.Yellowish, called yellow fibrous tissue
C. Abundant in vocal cords
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1. Loose connective: AkA: areolar
Appearance:
1.bundles of interlacing collagen fibers
with single interlacing elastin fibers
2. Fibroblasts, macrophages,and fat cells
- One of most widely distributed tissues
Location in body:
Fills spaces between organs and parts of organs
Fx:- connects many adjacent structures in bodyacts like “elastic glue”/- “Packing tissue”- fills
spaces
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Loose Connective: Areolar
• STRUCTURE:
– Mixed up mess
– Contains “bit” of
everything
• FXN:
– “Packing” material
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A.
B.
C.
D.
E.
F.
2. Elastic/Yellow Elastic
Connective Tissue
(Characteristics)
Consists mostly of elastic fibers
Appear as short, kinky, hair-like threads
Few cells present
Has yellowish color
Can be stretched
Found: part of arterial walls, lung tissue,
and air passages
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Elastic Connective Tissue
• Black = elastic fibers,
• Pink = collagen fibers
• Nuclei are mostly fibroblasts
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Elastic Connective
• Wrinkles
Loss of elastin over time
as you age. Skin
(epithelial tissue sags
over it)
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3. Adipose Tissue (Fat)
A. Fat tissue- special type of loose
connective in which cells are filled with
fat
B. Widely distributed in body
C. Appearance: large cells with a single
vacuole containing a droplet of fat
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Adipose tissue (Fat)
• STRUCTURE:
– Flattened nuclei
– Filled with dietary fat
Location: Deeper layer
of skin, organ
padding, yellow
marrow
• 3 Fxn’s: Reduces
heat loss, energy
storage, protection of
organs
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4. Fibrous (Dense) Connective
Tissue: tendons, liagaments,
fascia
a. Composed largely of strong
collagenous fibers (few cells)
b. Arranged in wavy parallel
bundles
c. Matrix between bundles
contain cells, rows of
fibroblasts
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Fibrous connective-cont.
d. Silvery white, strong and tough
e. Little elasticity (can resist tension in all
directions)
f. Sparingly supplied with blood vessels
(slow to heal)
fx:
1. form ligaments(bone to bone) (See knee model)
2. make up tendons (muscles to bone)
3. sheets cover muscles, whites of eyes , dermis of skin
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Tendons
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5. Cartilage
a. Network of fibers in rubbery ground
substance
b. Flexible but firm. Does not contain
minerals found in bone
c. There are 3 types
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Cartilage
• Location of 3 types:
1.Elastic:ribs attach
sternum,tip of
nose/ears
• 2.Fibro: between
vertebrae
• 3.Hyaline: trachea
• STRUCTURE:
– “chondrocytes”
scattered in groups
throughout matrix
– Avascular
• FX:
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– Provide flexible support
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Osseous tissue (Bone)
• Good blood supply
allows for fast
healing from
breaks/fractures
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7. Blood
-Serves as a transporting fluid- oxygen,
nutrients, hormones, wastes
-*Its matrix is called: plasma*
- Formed by special tissue in red marrow
Plasma is composed of:
a. Erythrocytes- red blood cells
b. Leukocytes- white blood cells
c.Thrombocytes-cell fragments called platelets
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Blood
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Nervous
th
Tissue-4
type of
tissue
-It is sensitive to changes in surroundings.
- Basic unit is the Neuron: a nucleus with long
and branching cell processes
a.dendrite --- carries impulses towards the cell body
b. axon ---- carries impules away from the cell body
• Location: brain, spinal cord, and nerves.
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Nerve Tissue
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Quick Quiz
• 1. Give 2 of the 4 major functions of
epithelial tissue.
• 2. What is the difference between simple
and stratified?
• 3. Name 3 types of muscle tissue, give
example of location for each
• 4. Name two differences that exist
between the different types of connective
tissue
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Quick Quiz:
• 5. Name two things that all connective
tissues have
• 6.Explain how the anatomy of loose
connective tissue relates to its physiology
• 7. What is the cause of wrinkles besides
the sun?
• 8. Why do ACL (sprains/strains) heal
slower than bone breaks?
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• 9. What is the name for bone cells?
• 10. What is name for cartilage cells?
• 11. How does a neuron work?
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