Histo Lecture 4

  1. Basement of the epithelium
    basal lamina
  2. Parenchyma
    • -Epithelial portion of organs
    • -Cells of an organ that provide function (i.e. hepatocyte)
  3. Stroma
    • -Supporting connective tissue of organ
    • -Connective tissue serves as support , structure, and protection of epithelial cells of the organ
  4. Name 5 functions of epithelium
    • -Covering/lining surfaces (skin, mucus, GI tract, blood vessels)
    • -Absorption (intestines)
    • -Secretion (glands: salivary, intestinal)
    • -Sensation (neuroepithelium: taste and smell)
    • -Contractility (myoepithelium of sweat, salivary, lacrimal)
  5. 4 Types of Epithelium
    • -Shape
    • -Specializations
    • -Number of Layers
    • -Function
  6. 3 Types of Epithelial shapes
    • -Squamous
    • -Cuboidal
    • -Columnar
  7. 4 types of epithelial specialization
    • -Cilia
    • -Microvilli
    • -Goblet cells
    • -Keratinization
  8. 4 Types of epithelial layering
    • -Simple
    • -Stratified
    • -Pseudostratified
    • -Transitional
  9. 3 types of epithelial function
    • -Covering epithelia
    • -Glandular epithelia
    • -Secretory cells
  10. All epithelial cells rest on an extracellular matrix called:
    basal lamina
  11. 4 functions of basal lamina
    • -Supports the epithelial cells above
    • -Acts as a diffusion barrier with pores that are semi-permeable
    • -Controls cell organization and differentiation
    • -Pathway for cell migration during development and healing
  12. 5 Components of basal lamina
    • -Type IV collagen
    • -laminin
    • -heparan sulfate
    • -fibronectin
    • -carbohydrates
  13. Example of simple squamos and function
    • -lining of vessels; serous lining of cavities
    • -Facilitates movement of viscera; Active transport of substances
  14. Example of simple cuboidal and function
    • -Covering the ovaries or thyroid
    • -Covering, secretion
  15. Exampe of simple columnar and function
    • -Lining of intestine or gall bladder
    • -Protection, lubrication, absorption, secretion
  16. Give example of Pseudostratified columnar and function
    • -Lining of trachea, cronchi, nasal cavity, intestines
    • -Protection, secretion, cilia-mediated transport, goblet cells, absorption
  17. Give example of Keratinized Stratified and function
    • -Epidermis
    • -Protection, prevents water loss
  18. Give example of Non-keratinized Stratified
    • -Mouth, esophagus, vagina, anal canal
    • -Protection, secretion, prevents water loss
  19. Give example of Stratified Cuboidal
    • -Sweaet glands, ovarian follicles
    • -Protection, secretion
  20. Give example of Stratified Transitional and function
    • -Bladder, ureters
    • -Protection, distensibility
  21. Give example of Stratified Columnar and functino
    • -Conjunctiva
    • -Protection
  22. How does simple squamous and cuboidal epithelium transport substances?
    Active & passive
  23. Function of goblet cells and where they are found
    • -Mucus secreting cells of epithelial tissues
    • -Found primarily in the intestinal and respiratory tracts
  24. Give an example of Transitional Epithelium and where it is located
    • -Lining the bladder and ureters
    • -Protction and distensibility
  25. How do Facet cells function?
    Change shape according to degree of bladder distention (cuboidal to squamos)
  26. Epithelial cells receive their blood from capillaries and nerve endings from plexuses in the unerlying:
    lamina propria
  27. Definition of Communicating Junctions (Gap Junctions)
    Control passage of chemical or electrical signals from cell to cell
  28. Function of Occluding Junctions (Tight Junctions)
    • -Seals cells together in a sheet-like formation
    • -Prevents movement of molecules between cells
  29. Function of Anchoring Junctions (Desmosomes/hemidesmosomes)
    -Attach cells to other cells or to extracellular matrix
  30. Name the units that Gap Junctions contain and describe their characteristics
    • -Connexon-Pair of 6 protein span lipid bilayer of adjacent cells
    • -Each protein of connexon is called connexin
    • -Permeability of gap is controlled by individual connexins
    • -Cells are able to control permeability of these junctions
    • -Serve as communicating junctions between adjacent cells
    • -Gap junctions are important for coordinated, synchronized cell excitation (smooth/cardiac muscle contraction)
  31. Structure of Tight Junctions
    • -Membranes of adjacent cells fuse, prevent material from moving between cells
    • -Junction forms a "band" completely encircling adjacent cells
  32. Function of Tight Junctions
    • -Prevent diffusion
    • -Provides waterproofing
    • -Prevent molecules from moving out of the gut lumen
  33. Structure of Desomosomes
    • -Intracellular attachment protein that connects desmosome to intermediate filament in cytoplasm
    • -Widely distrubed in animal cells
  34. Function of Desmosomes
    • -Serve as anchoring junctions to bind cells together
    • -Attachment sites for intermediate filaments of cytoplasm
    • -Transmembrane linker protein (cadherin)
    • -Hemidesomosomes bind cells to basal lamina
Card Set
Histo Lecture 4