1. Tissues
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2. Cells
Tissues
Organs
Organ systems
Organisms
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3. Tissues
Groups of cells with a common structure and function—similar cells work together at one job.
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4. Epithelial Tissues
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5. Introductory Questions
What is the function of epithelial tissue?
List some locations in which it is found.
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6. Epithelial Overview General definition Structure Function Types Simple
Squamous, cuboidal, columnar
Stratified
Squamous, columnar, transitional
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7. Epithelial Tissues Structure Tightly-packed cells
Little material between cells
Cover or line organs or body cavities
Has free side
Basement layer—non-living and separates epithelial from underlying connective tissue
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8. Epithelial – Structure
Classified by:
1) Number of layers
Simple – single layer
Stratified – multiple layers
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9. Epithelial – Structure
Classified by:
2) Shape of cells
Squamous – fried egg, tiles
Cuboidal – cube
Columnar - brick
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10. Epithelial Tissues Function --Secretion --Absorption
Protective—Barrier to:
-water loss
-microbes
-mechanical injury
--Secretion
--Absorption
--Sensory reception
--Movement
-Cilia
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11. Types of Epithelial Cells
1) Simple
A) Squamous
Single layer
Flat cells
Passage ways such as lungs, arteries, mesentary
Places of diffusion, filtration & secretion—alveoli, capillaries, lymph vessels
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12. Types of Epithelial—Simple
B) Cuboidal
Single layer
Cube-shaped
Covers and lines
Forms tubes/glands
Pancreas, kidney, salivary glands
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13. Types of Epithelial—Simple
C) Columnar
Single Layer – nuclei often on same level
Tall, elongated cells
Lining tissues
Digestive, uterine
Secretion – goblet cells secrete protective mucus
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14. Types of Epithelial 2) Stratified A) Squamous Layered
Often keratinized (protein hardens—water stays inside & chemicals & microorg. kept out) – outermost skin, areas of high stress
Non-keratinized -Mouth, rectum, vagina, esophagous
Types of Epithelial
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15. Types of Epithelial—Stratified
B) Transitional
Many cells thick
Elastic
Bladder, ureters
Appearance
Stretched or relaxed
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16. Types of Epithelial—Stratified
C) Columnar, pseudo- stratified
Appears layered due to nuclei on multiple layers
Often ciliated
Moves product
Respiratory tract
Fallopian tubes
Goblet cells secrete mucus & cilia sweeps away.
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17. The ink of tattoos must be injected below the basement membrane.
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18. Where does all the dead skin you shed go?
It takes about 27 days for the outer layer of skin to shed and be replaced; that works out to 1.5 pounds of skin cells per year.
Where does all the dead skin you shed go?

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