Epithelium

Question 1

• Epithelia lines? Function? (6)
• Types of simple? (3)
• Types of stratified? (2)
• Types of psuedostratified? All touch?
• Trasitional?
• Polarity occurs where? Maintained via? (3)
• Cell junctions:
  1. ) Tight junctions: Seal formed to seperate? Proteins used? (2) Molecules must travel?
  2. ) Adherins Junctions: Provide? Important for? Made of? Which interact with? What are desmosomes? Prominant where?
  3. ) Gap junctions: Form passages for ions to pass via? Exist mostly where?

Answer 1

• Tubes of the body; protection, active transport, detox, communication, move substances, respond to stimuli
• squamus, cuboidal, columnar
• squamus, columnar
• columnar; BL
• Change depending on mechanical stress
• Both membrane and intracellular level; cytoskeleton, pumps and membrane composition
  1. ) Apical from BL; occludins and claudins; through the cell and not between them
  2. ) Structural integrity; signalling; cadherins; actin; type of cadherin that interacts with intermediate filaments; skin
  3. ) Diffusion; cardiac muscle cells

Question 2

Cell Surface modifications:

1. ) Microvilli: Small protrusions loaded with? Important for?
2. ) Cilia: Long wavy arms made of? Important for?
3. ) BL infolds and outfolds: Increase what? Important for? Less organized than?
   - Basal lamina made of? Functions? (5)
   - Integrins attach what? What is hemidesmosome? What are focal adhesions? Control what? Other functions? (3)

Answer 2

• Actin; absorption
• Microtubules; moving substances along epithelium
• Surface area; transport; apical side
• Collagen and laminin; connect tissues, barrier, allow filtration, control polarity, info scaffolding
• Epithelia to BL; integrin that interacts with intermediate filaments; similar to adhesion junctions and attach to actin; polarity; transport, signals and gene expression

Question 3

• Exocrine glands: Secrete onto? Generally? 2 components? Functions? 2 types of secretions?
• Endocrine glands: Ducts? Secrete where? Surrounded by? Rich in? Hormone route? (4)
• Epithelia to mesenchymal transition: Embryonic epithelia disassembles and move to? After that?
• Epithelia stem cells: Characteristics? (4) Live where? Divide how? What is slightly different?

Answer 3

• Apical side; multi cellular; acini secretory units = produce and secrete and ducts for passage and modifications; carb rich mucus and watery serous
• No; into blood stream; CT; vascularity and BL; BL membrane –> BL –> CT –> Endothelium of cap
• CT mesenchyme; migrate to new tissue or transform to non-epithelial cell lineages
• Proliferative, self-renewing, capable of cell division, can produce different cell types; bottom of crypt; slowly; skin division

Question 4

• Cancer of epithelia? of exocrine tissue?
• 5 signal systems?
• 3 steps in Wnt pathway? What inhibits?
• LOF in WNT 7a =? Increased WNT 7A?
• How are tissue sections made? (6)

Answer 4

• Carcinoma; adrenocarcinoma
• Wnts, sonic, Notch, RTK, TGFB
• Wnt binds receptor, B catenin enters nucleus, increased cell division and decreased differentiation; APC inhibits B catenin
• Increased colon and ovarian cancer; increased lung cancer
• Biopsy, section, put on slide, fix with chemical, slice, stain