2 - Epithelium

  1. characteristics of epithelium
    • -polarity: basal, apical
    • -sheets: high cell/extra-cellular space ratio
    • -avascular: which limits thickness
    • -origins: ectoderm, mesoderm, endoderm
  2. intercellular juntions in epithelium
    zonula - strip

    macula/plaque - spot
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  3. epithelial classifications:
    simple, layered, pseudostrafied, transitional
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  4. epithelial surface specializations
    • cilia-movement
    • microvilli-increase the surface area of cells
    • keratin-form a dense meshwork of filaments throughout the cytoplasm of epithelial cells
  5. functions of epithelial tissue
    • -protection
    • -regulation of materials into/out of organs or tissues
    • -produce secretions: endocrine/exocrine glands
  6. epithelia: glandular
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  7. types of secretions
    • serous-minimizes friction between surfaces in interior cavities (tears, digestive juices, milk, sweat)
    • mucous-protects, lines cavities that conncect to exterior ( mouth, mucous)
  8. modes of secretion
    –Merocrine: exocytosis (tear glands)
    –Apocrine: sweat glands and mammary glands
    –Holocrine: mixture of cell fragments and sustances synthesized in the cells (oil glands on scalp
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  9. exocrine
    secretion exits via ducts
  10. endocrine
    ductless glands; release shit straight into bloodstream
  11. epithelial overview/review
    • -lines every body surface and cavitiy
    • -external and internal lining of many organs
    • -constitutes the majority of glands
    • -polarized cells
    • -high cell/ecm ratio
    • -avascular: no blood vessels penetrate an epithelium
Card Set
2 - Epithelium
exam 1 review