Lecture 01 and 02, Epithelia and CAMs/Junctional Complexes

Question 1

What are the two layers of the basement membrane

Answer 1

Basal Lamina and Reticular Lamina

Question 2

What produces the Basal Lamina?

Answer 2

Epithelium

Question 3

What produces the Reticular Lamina?

Answer 3

Connective Tissue

Question 4

What are the 4 components of the Basal Lamina?

Answer 4

1. Laminin 2. Type 4 Collagen 3. Entactin (nidogen) 4. Proteoglycans

Question 5

What are the characteristics of Laminin

Answer 5

major component of the basal lamina made of 3 chains: Alpha, beta and gamma binding sites for integrins, type 4 collagen, enactin and proteoglycans (heparan sulfate)

Question 6

What are the characteristics of Type 4 collagen

Answer 6

Does not form fibrils like type 1 Produced by epithelial cells, unlike type 1 collagen that is made by fibroblasts.

Question 7

What are the characteristics of fibronectin?

Answer 7

binding sites along the laminin made of two polypeptide chains that are cross linked by DISULFIDE bonds

Question 8

What are the forms of fibronectin?

Answer 8

Cellular- made by the fibroblasts, part of the extracellular matrix and Plasma- secreted into the blood stream by hepatocytes.

Question 9

What are the binding sites on Fibronectin?

Answer 9

1. Heparin (proteoglycan) 2. Integrins 3. Collagen 4. Fibrin

Question 10

Which are the molecular complexes that primarily serve to prevent paracellular transport?

Answer 10

zonula occludens

Question 11

Simple, non‐ciliated columnar epithelium is most like to be found associated with what?

Answer 11

Digestive tract. Note: different modifications to the apical domain happens along the GI tract, depending on the function.

Question 12

Junctional complexes are associated with which cellular domains?

Answer 12

basolateral domain

Question 13

Transitional epithelium is associated with which of the following?

Answer 13

Urinary bladder and parts of the ureters

Question 14

The extracellular domains of which of the following bind to molecules in the extra cellular matrix such as fibronectin and laminin?
A. Cadherins

B. Integrins

C. Selectins

D. Immunoglobulin Superfamily

Answer 14

B.

Integrins

Question 15

Stratified cuboidal epithelium may be found where?

Answer 15

parts of the male urethra

Also the anal mucosa and large excretory ducts of some glands

Question 16

Lightly keratinized stratified squamous epithelium is characteristic of which location?

Answer 16

vaginal epithelium

lining of mouth

esophagus

tongue

and part of the epiglottis

Question 17

Which of the following serve as a major interface between the cadherins that hold adjacent cells together and their actin cytoskeletons?
A. Proteoglycans

B. Catenins

C. Laminins

D. Keratins

Answer 17

C. Catenins

Question 18

Which of the following are molecular complexes that anchor cells together and reinforce the physical integrity of tissues and the cells that make up the tissues?

Answer 18

zonula adherens

Question 19

Which of the following types of cell adhesion molecules is associated with zonula occludens and desmosomes?

Answer 19

cadherins

Question 20

Which of the following are only associated with the basal domains?

A. zonula adherens

B. zonla occludens

C. Hemidesmosomes

D. Desmosomes

Answer 20

hemidesmosomes,

note: Integrins can be found on both the basal and the lateral domains

Question 21

The basal lamina is associated with which type of collagen?

Answer 21

type IV

Question 22

Desmocollins and desmogleins belong to which of the following groups of CAMs?

Answer 22

Cadherins

Question 23

Which of the following are molecular complexes that primarily serve to prevent paracellular transport?

Answer 23

zona Occludens

Question 24

Where can ciliated epithelia be found? Why is this particlar cell type found in those places?

Answer 24

Trachea, cilia promote the removal of irritants from the upper respiratory tract. Additionally, the ciliary elevator works to help the body dispose of trapped particles within the lungs.

Oviduct: cilia helps to “wave” the ovum down the oviducts to the uterus

Question 25

Which two types of cell adhesion molecules are considered CALCIUM DEPENDENT?

Answer 25

1. Cadherins 2. Selectins

Question 26

What two types of CAMs are Calcim INDEPENDENT?

Answer 26

the immunoglobin superfamily and integrins

Question 27

Why doesn't epithelium get it's nutrients from the blood stream? How does it receive nutrition?

Answer 27

The epithelium is avascular. Nutrients are passed by diffusion.

Question 28

Describe a highly keratinized cell, what unique feature can we look for to help us classify?

Answer 28

The nucleii of a highly keratinized cell is absent.

Question 29

What type of epithelium would we expect to find lining blood vessel walls?

Answer 29

Simple Squamous

Question 30

Which type of epithelial tissue can be found in the collecting tubules of the kidneys, and thyroid follicles?

Answer 30

Simple Cuboidal

Question 31

What type of epithelial cells is a host to a goblet cell?

Answer 31

Simple columnar Epithelium. Remember that the goblet cells do not stain on the slide, they are easy to see.

Question 32

The epidermis is primarily composed of ____________ epithelia

Answer 32

stratified squamous (abundant keratin)

Question 33

What type of epithelial cells would I find in my trachea?

Answer 33

Pseudostratified columnar epithelia

Question 34

What type of epithelia would I find in the epididymis?

Answer 34

Pseudostratified Columnar with stereocillia.

Question 35

In the epididymis, what type of cells have highly developed Golgi Apparatus's?

Answer 35

Principal Cells, and they are the only type of cell to actally reach the lumen.

Question 36

What ligands do cadherins recognize?

Answer 36

other cadherins

Question 37

What type of ligands do the selectins recognize?

Answer 37

Carbohydrates

Question 38

What type of CAMs lock the cell to the matrix?

Answer 38

Integrins (using a hemidesmosome)

Question 39

The annoying immnoglobulin superfamily recognizes what type of ligands?

Answer 39

integrins

Question 40

Which type of Cadherins form dimers? (They are also the most common)

Answer 40

E-cadherins EPITHELIAL

Question 41

Where might you find epithelia that could form a leaky barrier?

Answer 41

lining of gall bladder PCT of nephron

Question 42

What specific type of epithelia offers protection from wear and tear

Answer 42

stratified sqamous epithelia

Question 43

Stratified Columnar epithelia is rare. Name places you can find it...

Answer 43

1. Sweat ducts (adult) 2. Fornix of the conjunctiva of the eye 3. parts of the male urogenital tract 4. pharynx 5. epiglottis

Question 44

What is the difference between an Adherens and Occludens?

Answer 44

Aderens are the molecular complexes that anchor cells together and reinforce the physical integrity of tissues and the cells that make up the tissues. FOUND: basolateral surfaces Ocludens are the molecular complexes that establish an impermeable barrier between adjacent cells. PREVENTS paracellular transport and maintains concentration differences, nothing in... nothing out.

Question 45

Define Gap Junction

Answer 45

make up of molecular pores that allow cells to rapidly exchange ions and other molecules. They help coordinate activities among the cells that make up the tissue.

Question 46

What are the two types of junctional complexes?

Answer 46

Zonula (adherense or occludens) and Macula (spot or snap like junction)

Question 47

Which type of junction is associated with intracellular intermediate filaments (tonofilaments?)

Answer 47

Macula adherens

Question 48

Which type of junction is associated with intracellular actin?

Question 49

Where can you find Desmogein 1 and 2?

Answer 49

Epidermis!

Question 50

What is the clinical importantce of autoantibodies to desmoglein1?

Answer 50

Autoantibodies to desmoglein 1 result in pemphigus foliaceus... of course

Question 51

What do Desmoplakin and Plakoglobin have in common?

Answer 51

They are present in the plaques associated with cadherin proteins

Question 52

Which proteins do the Claudins and occludins attach to inteacellularly?

Question 53

JAMS and nectin are members of what group?

Answer 53

immunoglobulin superfamily

Question 54

Tell me about connexons... what are 3 things mentioned in lecture?

Answer 54

1. Each connexon consists of 6 connexins, forming hexagonal structure with a hollow center. 2. Connexons facilitate movement of molecules up to 1.2 nm in diameter 3. Connexons are often clustered into patches. \*\*Focus on unique components, and how do they tie into the functions of the junction

Question 55

When do gap junctions close?

Answer 55

Gap junctions close when calcium ion concentrations are high!

Question 56

What are two clinical isses that arise from pathologies of gap junctions?

Answer 56

Charcot-Marie-Tooth neuropathy and Congenital cataracts