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Tissues

Introduction• Cells become specialized to perform specific functions

– Tissues are: groups of similar cells that perform the same function

• Tissues differ from each other in:• 1. size, • 2. shape• 3. arrangement, • 4. function

4 TISSUE TYPESFour 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

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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 muscleA. 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 Tissue1. 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 tissuesLocation in body:

Fills spaces between organs and parts of organs

Fx:- connects many adjacent structures in body-acts 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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2. Elastic/Yellow Elastic Connective Tissue(Characteristics)

A. Consists mostly of elastic fibers

B. Appear as short, kinky, hair-like threads

C. Few cells present

D. Has yellowish color

E. Can be stretched

F. 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,

fasciaa. Composed largely of strong

collagenous fibers (few cells)b. Arranged in wavy parallel

bundlesc. 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/end of long bones

• STRUCTURE:– “chondrocytes”

scattered in groups throughout matrix

– Avascular

• FX: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 Tissue-4th 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

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 36

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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