cells and tissues 2

Question 1

what are the layers of the basement membrane?

Answer 1

lamina lucida (top)
lamina densa (bottom)

Question 2

what is laminin?

Answer 2

protein of the basal lamina

Question 3

explain the cause of Marfin’s syndrome

Answer 3

connective tissue disorder

elastin normally polymerises into fibrils and fibrillin coats it which limits how far it can stretch

in marfan’s, the fibrillin is misfolded so allows body parts to stretch abnormally - elastin cant recoil

Question 4

what type of collagen is the basement membrane?

Answer 4

collagen type 4

Question 5

name a disease caused by the mutation of laminin

Answer 5

junctional epidermolysis bullosa

Question 6

explain the cause of junctional epidermolysis bullosa and how it presents

Answer 6

laminin is mutated
skin v fragile
blisters form in the lamina lucida

Question 7

what are the types of epithelial junctions?

Answer 7

tight
gap
adherens
hemidesmosomes
desmosomes

Question 8

what do tight junctions do?

Answer 8

prevent passage of molecules across the epithelium

Question 9

what do adherens do?

Answer 9

tether adjacent cells together

Question 10

what do desmosomes do?

Answer 10

resist mechanical stress

Question 11

what do gap junctions do?

Answer 11

allow small passage of molecules through

Question 12

what do hemidesmosomes do?

Answer 12

anchor epithelium to basal lamina

Question 13

where are lots of desmosomes found?

Answer 13

in the heart

Question 14

what do mutations of demosomes generally cause?

Answer 14

diseases of the skin and heart (impaired cardiac function)

Question 15

what causes pemphigus vulgaris?

Answer 15

immune system attacks desmosomal proteins using autoantibodies causing epidermal blisters

Question 16

what causes Staph. scalded skin syndrome?

Answer 16

when bacterial proteins are aimed at the desmosomal cadherins causing epidermal blisters

Question 17

what causes Naxos disease and how is it presented?

Answer 17

genetic disease - mutation of desmoplakin

causes skin blisters, cardiomyopathy and wooly/curly hair

Question 18

what is the function of non-motile cilia?

Answer 18

sensory antennae on all cells

Question 19

what is the function of motile cilia?

Answer 19

to move things along

Question 20

name some diseases of the cilia?

Answer 20

Bardet-Biedl syndrome
Polycystic kidney disease - abnormal primary cilia function
Ectopic pregnancy - lack of cilia in the fallopian tube

Question 21

name the structures needed in cell movement and what they look like

Answer 21

pseudopodia - cytoplasmic projections
lamelliopodia - ruffles (cell migration)
filopodia - spikes (sense environment)

Question 22

what does Escherichia coli target?

Answer 22

intestinal microvilli and junction

Question 23

what does infection of Escherichia coli cause?

Answer 23

malabsorption

osmotic diarrhoea

Question 24

what is the reticular lamina?

Answer 24

where the basement membrane attaches to the ECM protein

Question 25

what is laminin?

Answer 25

protein of the basal lamina

Question 26

what is connecitve tissue?

Answer 26

tissue that lies between 2 other tissues

Question 27

what are the types of connective tissue?

Answer 27

``` loose dense bone and cartilag adipose blood ```

Question 28

what are the cells that make connective tissue?

Answer 28

``` fibroblast adipocyte chondroblasts osteoblasts haemopoietic cells ```

Question 29

what are the functions of ECM?

Answer 29

``` determines the function of the tissue has a role in; o Cell migration o Shape of the cell o Cell proliferation o Survival o Tissue development ```

Question 30

what are the main macromolecules of the ECM?

Answer 30

GAGs and fibrous proteins

Question 31

what are the main fibrous proteins in the ECM?

Answer 31

collagen elastin fibronectin

Question 32

where are proteoglycans assembled?

Answer 32

ER and golgi

Question 33

how do proteoglycans get to the ECM?

Answer 33

secretory vesicles

Question 34

how do GAGs and proteoglycans resist compressive forces?

Answer 34

by binding water and forming hydrated gels

Question 35

what is the advantage of hydrated gels?

Answer 35

resist compressive forces | permit rapid diffusion of nutrients, hormones and metabolites through them

Question 36

give examples of sulfated GAGs

Answer 36

o Chondroitin sulfate o Heparin sulfate o Dermatan sulfate

Question 37

what is hyaluronic acid used in?

Answer 37

wound healing cell migration growth joints

Question 38

what are proteoglycans?

Answer 38

protein core with GAGs attached

Question 39

give examples of proteoglycans?

Answer 39

biglycan aggrecan syndecan

Question 40

how does collagen form fibrils?

Answer 40

collagen filaments polymerise to form fibrils

Question 41

what is Ehlers Danlos syndrome?

Answer 41

small collagen fibres which don’t come together so the skin can be pulled away – not held to the skin tightly. If it’s pulled too hard it would shear and tear.

Question 42

what can fibronectin bind to?

Answer 42

cells via integrins | ECM via collagen

Question 43

what are the roles of fibronectin?

Answer 43

cell attachment matrix organisation cell migration development and wound healing

Question 44

what does the basement membrane separate?

Answer 44

epithelium and underlying connective tissue

Question 45

what is the basement membrane made of?

Answer 45

collagen type 4, laminin, heparan sulfate proteoglycan and entactin

Question 46

what are the roles of the basement membrane?

Answer 46

support anchoring filter signalling

Question 47

what happens to the basement membrane in cancer?

Answer 47

basement membrane breaks down so the cancer can metastasise

Question 48

what do the toxins of Escherichia coli cause?

Answer 48

``` o Destroy:  Intestinal microvilli  Intestinal junctions o Inhibit:  Water reabsorption ```