MS - Anat & Phys (Epidermis & Epithelial cell junctions) Flashcards
Pg. 410 in First Aid 2014 Sections include: -Epidermis layers -Epithelial cell junctions
List the epidermis layers from surface to base.
From surface to base: (1) Stratum Corneum (keratin) (2) Stratum Lucidum (3) Stratum Granulosum (4) Stratum Spinosum (spines = desmosomes) (5) Stratum Basale (stem cell site)
What are the 5 types of epithelial cell junctions?
(1) Tight junction (2) Adherens junction (3) Desmosome (4) Gap junction (5) Hemidesmosome
What is another name for Tight junction? What is its function?
Tight junction (zonula occludens) - prevents paracellular movement of solutes
What 2 substances make-up tight junctions?
Composed of claudins and occludins
What is another name for Adherens junction? Where is it found?
Adherens junction (zonula adherens) - below tight junction
What function does Adherens junction serve, and how?
Adherens junction (zonula adherens) - below tight junction, Forms “belt” connecting actin cytoskeletons of adjacent cells with CADherins (Ca2+-dependent adhesion proteins); Think: “CAD = Ca2+-dependent ADhesion proteins”
What does the loss of E-cadherin promote? To what epithelial cell junction does this relate?
Loss of E-cadherin promotes metastasis; Adherens junction (zonula adherens)
What is another name for Desmosome? What is its function?
Desmosome (macula adherens) - structural support via keratin interactions
In what condition are autoantibodies formed against desmosome?
Autoantibodies –> pemphigus vulgaris
What function do Gap junctions serve, and how?
Gap junctions - channel proteins called connexons permit electrical and chemical communication between cells
Give the main substance/building block(s) involved in each of the following epithelial cell junctions: (1) Adherens junction (zonula adherens) (2) Desmosome (macula adherens) (3) Gap junction.
(1) E-cadhedrin, Actin filaments (2) Keratin, Desmoplakin (3) Connexon with central channel
What function does Hemidesmosome serve?
Hemidesmosomes - connects keratin in basal cells to underlying basement membrane
In what condition are autoantibodies formed against hemidesmosome?
Autoantibodies –> bullous pemphigoid; Think: “Hemidesmosomes are down “BULLow”)
What are Integrins, and what function do they serve in the epithelium?
Integrins - membrane proteins that maintain IntegrIty of basolateral membrane by binding to collagen and laminin in basement membrane; Think: “INTEGRIns = INTEGRIty”
Draw epithelial cells, drawing and labeling the major cell junctions and related components.
See p. 410 in First Aid 2014 for visual at bottom
