epithelial tissue. general location body coverings body linings glandular tissue
TRANSCRIPT
Epithelial Tissue
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GENERAL LOCATION
• Body coverings
• Body linings
• Glandular tissue
GENERAL FUNCTIONS
• Protection
• Absorption
• Filtration
• Secretion
GENERAL CHARACTERISTICS• Cells fit closely together
• Tissue layer always has one free surface
• The lower surface is bound by a basement membrane
• Avascular (no blood supply)
• Regenerates easily if well nourished
CLASSIFICATIONNumber of Cell Layers
-Simple: one cell layer
-Stratified: more than one cell layer
Cell Shape
-Squamous: flattened
-Cuboidal: cube-shaped
-Columnar: column like
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TYPES OF EPITHELIAL TISSUE
o Simple Squamous
Structure: single layer of flat cells
Function: forms membranes; lines
body cavities
Found in: capillaries, lining of lungs
SIMPLE SQUAMOUS
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Endothelium
• Specialized type of squamous cell that permits efficient diffusion of materials. Very fragile but this allows for rapid gas exchange. Found lining the heart, lungs, blood & lymph vessels.
TYPES OF EPITHELIAL TISSUE
o Simple Cuboidal
Structure: single layer of cube-like cells
often arranged around a space
(follicle)
Function: secrete fluids; absorption
Found in: kidney tubules; ovaries
SIMPLE CUBOIDAL
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TYPES OF EPITHELIAL TISSUE
o Simple Columnar
Structure: single layer of tall cells
Function: secrete mucus & enzymes;
absorption
Found in: the digestive tract lining
SIMPLE COLUMNAR
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Goblet cells
• Spherical cells that produce mucus - a lubricating material for the digestive tract
TYPES OF EPITHELIAL TISSUEo Psuedostratified (Ciliated)
Structure: hair-like projections
Function: absorption, secretion of mucus,
and aids in the movement of
particles
Found in: upper respiratory tract & reproductive
organs
PSUEDOSTRATIFIED (CILIATED)
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TYPES OF EPITHELIAL TISSUE
o Stratified
Structure: many cell layers
Function: protection in areas where friction
is common
Found in: skin, mouth, esophagus
STRATIFIED
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TYPES OF EPITHELIAL TISSUE
o Transitional
Structure: changes shape based on
amount of stretch
Function: allows for expansion
Found in: urinary tract/bladder lining
TRANSITIONAL
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SOURCES OF SLIDES
http://images.google.com/imgres?imgurl=http://www.stegen.k12.mo.us/tchrpges/sghs/ksulkowski/images/20_Simple_Columnar_Epithelial_Tissue.jpg&imgrefurl=http://www.stegen.k12.mo.us/tchrpges/sghs/ksulkowski/TissueSlides.htm&usg=__6bG6lRXNVq92ooXE_8vwTjeB25o=&h=467&w=700&sz=91&hl=en&start=3&um=1&tbnid=CJfwZ1avYGDPPM:&tbnh=93&tbnw=140&prev=/images%3Fq%3Depithelial%2Btissue%26hl%3Den%26sa%3DN%26um%3D1
http://www.unomaha.edu/hpa/2740epithelium.html#ss
Gland
• One or more cells that secrete a particular product
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TYPES OF GLANDS
Endocrine - ductless; secretions are
hormones that enter the blood
vessels
ex: thyroid, adrenal, pituitary
TYPES OF GLANDS
Exocrine - empty through ducts to the
epithelial surface
ex: sweat, oil, mammary, salivary
End.