Epithelium: Cell Junctions Flashcards Preview

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Flashcards in Epithelium: Cell Junctions Deck (62):
1

Name the asymmetric junction(s)

Hemidesmosome (attach cells to the basal lamina)

2

Name the symmetric junction(s)

(btwn two cells) Tight Junction (occluding junction) Anchoring Junction ( belt desmosomes) Anchoring Junction ( spot desmosomes) Communicating Junction (Gap)

3

Tight Junction (occluding)

No intercellular space -circumferential belts at the apical domain of epthelial cells -links adjacent endothelial cells -regulate the passage of ions between adjacent epithelial cells -

4

Transcellular Pathway

Across the cell controlled by channels and receptors

5

Paracellular Pathway

Between the cells regulated by intracellular contact and CELL JUNCTIONS

6

Actin filaments are seen in what type of Junction

Tight

7

What is anchored to Zo-1 in Tight Junctions

Afadin-nectin complex JAMS

8

What type of dimers do Nectins form

cis-homodimers transhomodimers

9

JAMS (Junctional adhesion molecules) attach to

afadin and ZO-1

10

JAMS determine...

formation of cell polarity

11

Order of Junctions from the Lumen down

Tight (occluding) Zonula adherens (belt) Macula adherens (spot)

12

Tight Junctions ..what interacts with F-actin

occludin claudins JAMS

13

What components of the tight junction are seen in freeze fracture?

Occludin and Claudins

14

What type of junctions are show from top to bottom

Line 1

Line 2

Line 3

 

Q image thumb

Tight Junction

Zonula adherens

Macula adherens

15

What type of Junction is this?

Q image thumb

Tight Junction (freeze fracture) occludin and claudins

16

What type of Junction is #2

What is inside this intercellular space ?

Q image thumb

Tight Junction

Occludin

Claudins

JAMS

Nectins

17

What type of Tight Junctions are part of the immunoglobin family of Cell Adhesion Moleculess?

Nectin and JAMS

18

Occludin and Claudin are part of what family of proteins?

Tetraspanins

19

What part of Tight Junctions are actin Linkers?

ZO

20

Tight Junctions separate which two domains?

Apical and Basolateral membrane domains

(prevent free diffusion of lipids and membrane proteins between them)

21

Tight Junctions regulate ...

Paracellular Pathway of fluid and solutes (kidney blood filtration)

22

Nectin and JAMS form homodimers through what bonds

disulfide bonds

23

What type of filaments are associated with tight junctions?

Actin (microfilaments) 

24

Freeze Fracture

Creates artifical (FACE)

Protoplasmic (wear bumps are seen) where occuludin and claudins seen

Extracellular face (where pits are seen)

results from spitting membrane across hydrophic core 

uses heavy metals to coat the cell

 

25

Occludin is attached to what ZO

ZO2

26

Clauddin is attached to 

ZO 4

27

Belt desmosome 

Zonula adherens

Afadin-nectin complex

plaques (desmoplakin, plakoglobin (gamma catenin), plakophillin) *anchor*

catenin ( alpha, beta, gamma) go wit cadherins connect to actin

cadherins ( desmocollins and desmogleins)

28

What is seen in both tight junctions and belt desmosomes?

Afadin-nectin complex

29

Plaques ( belt desmosomes)

Anchor

where cytoplasmic domains of cadherins attach to desmoplakin by plakglobin and plakophillin

30

Belt Desmosomes

belt like

actin filaments (interaction of cadherins with catenins)

wide extracellular space

31

Belt 

Cadherins

atttaches to cytoplasmic plaques on cystolicface of plasma membrane

1.desmocollins

2.desmogleins (1 &3 are in epidermis, if issue the pemphigus foliacus)

32

Pemphigus Foliacus

Blistering Disease

issue with Desmogleins 1 & 3 (affects epidermis)

33

What are the types of juntions seen?

Q image thumb

Top is Tight Junction

Bottom is belt desmosome ( can tell because of hte actin filaments but the extracellular space is further apart then the tight )

34

What are the anchoring desmosomes?

Spot

Belt

Hemidesmosome

35

Name a communicating Junction?

Gap

36

Name an occluding Junction?

Tight

37

Spot desmosome

macula adherens

Keratin/ tonomfilaments/ intermediate filaments 

Plaques ( plakoglobin, plakophillin, desmoplakin)

Cadherins (desmocollins and desmogleins)

add strenth and rigidty to epithelium layer

 

38

What is anchored to desmoplakin in spot desmosomes?

Intermediate filaments

39

Differences between belt desmosome and spot desmosome?

spot desmosome has 

intermeidate filaments (anchor directly to plaque)

and no catenins 

40

What type of desmosomes are seen in intercalated discs?

spot desmosomes

41

Role of Plakophillin

In plaues (spot and belt desmosomes)

recruit protiens to the plasma membranes

 

42

Disorder with Desmoglein (cadherin)

striate palmoplantar keratoderma (hypotrichosis)

43

Issue with desmoplakin (plaque)

ARVC, woolyhair

44

Issue with Plakoglobin

Naxos Disease

ARVC, wooly hair

palmoplantar keratoderma

45

In this picture of a spot desmosome what is the top line pointing to?

Q image thumb

intermediate filaments

46

Bullous Phemphigoid

autoimmune disease of the skin

BLISTER

deals with hemidesmosomes

Antibodies to BPAG1 or BPAG2 results in detachment of hemidesmosome fromt he basal lamina

 

47

Hemidesmosomes

Asymetric

BPAG1 and BPAG2

Integrins (beta 4 alpha 6) +pectin

Laminin 5

Intermediate filaments (anchored to the plaque) (inner cytoplasmic plate)

Plaque (DIFFERENT TYPE-NO DESMOPLAKIN, NO PLAKOPHILLIN AND NO PLAKOGLOBIN)

Inner cytoplasmic plate (IF)

outer cytoplasmic plate ( link hemidesmosome to basal lamina with lamisn and integrin)

aids with stability

 

48

Gap Junctions

(communicating junctions)

Link adjacent cells

Connexon: formed by 6 connexins surrounding a central channel

Inner channel: allows direct passage of small signaling molecules (calicum and camp)  between adjacent cells (helps with coordinating cell responses) 

hyrophiliic inner channel

49

What junctions tend to have a clustering tendancy?

Gap junctions

50

What junctions are seen in heart muscle cells?

Gap Junctions 

conduct electricity

51

Issue with Connexin 26

cochlea (deafness)

52

Issue with conexin 32

charcot marie tooth demyelinating neuropathay 1 

X linked

issue with Schawn Cells

53

Connexin 50

cataracts (blindness)

54

Connexin 43 and 45

Bone cells 

osteoclast/osteoblast

skeletal defects

55

Role of Basement membrane

supporting sheet epithelia

56

Integrins mediate

cell-matrix interaction

because of binding affinty to RGD domain in laminin and fibronectin (which are proteins of ECM)

57

Basal Lamina

laminin 

iv collagen

entactin (nidogen)

proteoglycans (heparn sulfate)

58

Reticlar Lamina

collagen fibers (III)

supports basal lamina with connective tissue

59

Things that are PAS POS

collagens

mucus (goblet)

glycocalyx

glycoproteins (pituitary gland)

basement membrane

60

Laminin

basal lamina

3 disuflfide linked polypeptide chains (alpha beta gamma)

binding sites for cells surface receptors (integrins), type IV collagen, nidogen

61

Fibronectin

glycoprotein

two identical chains joined by disulfide linkage close to C terminal

Two types

Cellular -produced by fibroblas (ECM)

Plasma- produced by hepatocyes  (bloodstream)

62