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16 Cards in this Set
- Front
- Back
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What are the four major tissue types?
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Epithelial
Connective Muscle Nervous |
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Locations of Epithelial Tissues:
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Cover body surfaces
Line body cavities Form glands |
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Functions of Epithelial Tissues:
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Protection
Absorption Secretion Excretion Filtration |
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What are the characteristics of Epithelial Tissues?
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-Usually found in sheets with tight junctions between cells.
-Very little intercellular material -Has a free or 'apical' surface which faces an open space -Oposite to the free surface is a connective tissue base -Epithelial Tissue (ET) is 'glued' to the CT base by a basement membrane. -There are no blood vessels that penetrate the ET - It is avascular -ET gets all its O2 and nutrients from the CT base via diffusion. -ET is very active in Mitosis. 1.Number of cell layers from bast to free surface |
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ET is classified by two criteria.
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1. Number of cell layers from base to free surface.
Simple = 1 layer. All cells touch the base and all reach the free surface. Stratified = >1 layer. No cells touch the base and reach the free surface. 2. Shape of the cells. squamous - thin and flat cuboidal - height = width columnar - tall and narrow |
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Types of Simple Epithelia
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Simple Squamous ET
Simple cuboidal ET Simple columnar ET Pseudostratified ciliated columnar ET |
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What is Simple Squamous ET?
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1 layer of thin flat cells.
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Where is Simple Squamous ET found?
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Kidney - filtration membrane (where blood is filtered)
lungs - walls of alveoli (forms air sacs of the lung) linings - lines body cavities that do not open to the outside circulatory system - lines inside of arteries, veins, capillaries, and heart - 'endothelium' |
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Where is Simple cuboidal ET found?
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Found in glands and forming the walls of tubules in the kidney.
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Where is Simple columnar ET found?
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Lines digestive tract. Has microvilli for absorption and special cells that secrete mucus (Goblet cells)
Lining of uterine tubes. Have cilia Lining of smaller airways (bronchi) |
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Pseudostratified ciliated columnar ET
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All cells touch the base, but all do not reach the apical surface.
Lines the larger airways in the respiratory system. Has both cilia and Goblet cells. *Note: Lines majority of Bronchi Cilia - propel mucus along the surface of the cell |
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What are the types of Stratified Epithelia?
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Stratified squamous ET
Stratified cuboidal ET Stratified columnar Transitional ET |
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Stratified squamous ET
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Has multiple layers, cells become flatter as the near the apical surface.
'Keratinized' stratified squamous has the protein keratin in it. Makes up the epidermis. 'Non-keratinized' has no keratin and lines high friction areas like esophagus, mouth, and vagina. *Note: Start out round at bottom, then they are flat and spread out as you reach the top. |
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Stratified cuboidal ET
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Very limited, found in seat and salivary glands. Always has just 2 layers of cells.
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Stratified columnar ET
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Rarest of all ET's. Found in male urethra.
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Transitional ET
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Cells change shape when stretched but still keep a tight fit to one another.
Found lining the urinary bladder and ureters. |
