Exam #1: ECM

Question 1

What are the molecular constituents of the ECM?

Answer 1

• Ground Substance

- Fibers

Question 2

What are the different types of ground substance?

Answer 2

• Glycosaminoglycans
• Proteoglycans
• Water
• Adhesive glycoproteins

Question 3

What are different fibers in the ECM?

Answer 3

• Collagen
• Reticular Fiber
• Elastic

Question 4

Reticular Fiber

Answer 4

Type III Collagen

Question 5

Granulation Tissue

Answer 5

• Replacing functional cells w/ ECM in response to injury
• Hallmark of tissue repair
• Loose, edematous, & vascular

Question 6

Mature Scar

Answer 6

Loose granulation tissue replaced with dense collagenous tissue

Question 7

How does the ECM drive the cell cycle?

Answer 7

• No contact w/ substrate= low probability of division
• Cell perched on adhesive patch= increases probability of division
• Cell spread on large adhesive patch= high probability of division

Question 8

Focal Adhesions

Answer 8

Connection between cell & ECM that regulate:

• cell division
• growth
• survival

Question 9

Injury to cell with intact matrix

Answer 9

Regeneration by functional cells

Question 10

Injury to cell & matrix

Answer 10

Repair by granulation & scarring (non-functional cells)

Question 11

What happens to the hydrated state of tissue when there is excessive accumulation of glycosaminoclycans?

Answer 11

Increase b/c of negatively charged carboxyl groups that attract water

Question 12

What are the different glycosaminoglycans that exist in the ECM?

Answer 12

• Dermatin Sulfate
• Chondroitin Sulfate
• Heparan Sulfate
• Keratan Sulfate
• Hyaluronic Acid
• Heparin

Question 13

Exopthalmous

Answer 13

• Grave’s Disease
• Autoantibodies to TSH
• Causes increased deposition of glycosaminoglycans in the retro-orbital space
• Specifically, Chondriotin Sulfate & HA
• Increases hydration state and pushes the eyes outward

Question 14

Proteoglycan

Answer 14

• “Bottle-brush” appearance
• Core protein with Glycosaminoglycans attached
• Link with HA to form an aggrecan

Question 15

Syndecan

Answer 15

• Transmembrane proteoglycan
• FGF receptors adjacent
• Co-receptor for FGF receptor
• Attached by Heparan Sulfate

Question 16

Perlecan

Answer 16

• Dark brown in appearance
• Found in the interface between epidermis & dermis
• Surrounds blood vessels
• Plays a role in the development of skeletal tissue

Question 17

Perlecan- Null

Answer 17

Defective skeletal development

Question 18

What are the three typical binding domains of a multiadhesive glycoprotein?

Answer 18

1) Cell adhesion molecule aka CAM e.g. Integrin
2) Collagen fibers
3) Proteoglycans

Question 19

What are the six types of adhesive glycoproteins?

Answer 19

1) Fibronectin
2) Laminin
3) Entactin
4) Tenascin
5) Chondronectin
6) Osteonectin

Question 20

Laminin

Answer 20

Adhesive Glycoprotein in Basal Lamina

Question 21

Entactin

Answer 21

Adhesive Glycoprotein in Basal Lamina

Question 22

Tenascin

Answer 22

Adhesive Glycoprotein in Embryonic Tissue

Question 23

Chondronectin

Answer 23

Adhesive Glycoprotein in Cartilage

Question 24

Osteonectin

Answer 24

Adhesive Glycoprotein in Bone

Question 25

What is the role of Fibronectin in development?

Answer 25

- Normal development of salivary glands | - When blocked, glands do not differentiate

Question 26

Laminin

Answer 26

Binding domains: - Dystroglycan (cell-adhesion molecule) - Collagen - Heparan Sulfate (proteoglycan) Plasma membrane of muscle

Question 27

What is the most abundant fiber type seen in the ECM?

Answer 27

Collagen

Question 28

Type I Collagen

Answer 28

- Most abundant - Associated with tendons, ligaments, fibrocartilage, cementum, dentin, bone, dermis, & any organ w/ a connective tissue capsule - Acidophillic (pink)

Question 29

Type II Collagen

Answer 29

- Hyaline & Elastic Cartilage

Question 30

Type III Collagen

Answer 30

- Reticular Cartilage - Spleen, liver, lymph nodes, smooth muscle, skin, lung - Forms a "delicate network" for cells - Argyrophilic (silver loving) - PAS positive (carbohydrates associated)

Question 31

Type IV Collagen

Answer 31

Basal Lamina

Question 32

Type VII Collagen

Answer 32

- Dermis | - Connects the basal lamina with the underlying dermis

Question 33

What amino acid is measured to calculate the concentration of collagen?

Answer 33

Hydroxyproline

Question 34

How is collagen turned over?

Answer 34

- Proteolytic Degradation | - Phagocytic Degradation

Question 35

What do cardiac muscle cells appear in response to a remote MI?

Answer 35

- Blue from collagen deposition (granulation first) | - Trichome method of staining

Question 36

Keloid

Answer 36

Excessive accumulation of collagen/ excessive scar formation

Question 37

What are Elastic Fibers composed of?

Answer 37

- Proelastin - Microfibril-associated glycoprotein - Fibrillin 1&2

Question 38

What are unique amino acids to elastic fibers?

Answer 38

Desmosine & Isodesmosine

Question 39

Ehler's Danlos Type IV

Answer 39

- Type III Collagen (Reticular Fibers) | - Varicose veins, aortic rupture, intestinal rupture

Question 40

Ehler's Danlos Type VI

Answer 40

- Defective Hydroxylation of Lysine | - Hyperelasticity of the skin, rupture of the eyeball

Question 41

Ehler's Danlos Type VII

Answer 41

- Type I Collagen | - Joint dislocation & hypermobility

Question 42

Marfan's Syndrome

Answer 42

- Defective synthesis of elastic fibers | - Aortic aneurysm, skeletal defects, pectus excavatum, scoliosis

Question 43

Basal Lamina

Answer 43

- Interface between epithelial cells & extracellular components/ underlying connective tissue - Found in epithelium, kidney glomerulus, & muscle cell

Question 44

Basement Membrane

Answer 44

- Basal Lamina ( Lamina lucida & Lamina densa) | - PLUS Lamina fibroreticularis

Question 45

Lamina Lucida

Answer 45

- Laminin - Entactin - Integrins - Dystroglycans

Question 46

Lamina Densa

Answer 46

- Type IV Collagen - Fibronectin - Perlecan

Question 47

Lamina Fibroreticularis

Answer 47

- Fibronectin - Type I Collagen - Type III Collagen

Question 48

What anchors the Lamina Densa to the Fibroreticularis?

Answer 48

Type VII Collagen

Question 49

Membranous Nephropathy

Answer 49

- Autoantibodies produced against antigens - Deposit in the basal lamina of the glomerulus - Compliment is activated - Leads to a degradation of the wall of the vasculature