Svensson Lec 1

Question 1

what is tissue regeneration?

Answer 1

Replacement of injured tissue with cells of the same type and function

Question 2

what is tissue repair

Answer 2

Occurs when extent or nature of damage cannot be reversed by regeneration alone

Question 3

State the 4 stages of healing after tissue injury.

Answer 3

1. hemostasis
2. inflammation
3. proliferation
4. remodeling

Question 4

describe hemostasis

Answer 4

1. Results in local vasoconstriction and activation of platelets and clotting factors to form a fibrin clot
2. Creates a scaffold for migrating cells
3. minutes

Question 5

describe inflammation

Answer 5

1. hours
2. Driven by platelet-derived mediators, bacteria, and secreted chemoattractants

Question 6

describe proliferation

Answer 6

1. days
2. Mediated by macrophage and fibroblast-derived growth factors

Question 7

describe remodeling

Answer 7

1. weeks to months
2. Transition from type 3 and type 1 collagen, restoring tensile strength of tissue

Question 8

State the common outcome of various signal transduction pathways of growth factors.

Answer 8

results in the change of gene expression

Question 9

what are the two forms of ECM and their key components

Answer 9

basement membrane and interstitial matrix

Question 10

describe the basement membrane

Answer 10

1. Type 4 collagen
2. Laminin
3. proteoglycan

Question 11

describe the interstitial matrix

Answer 11

1. Fibrillar collagens
2. Elastin
3. Proteoglycan and hyaluronan

Question 12

what are the determinants of regeneration vs. repair after tissue injury.

Answer 12

1. nature of cells injured
2. extent of injury
3. underlying disease
4. Presence or absence of ongoing inflammation

Question 13

describe the nature of cells injured

Answer 13

some cells (ex: adult cardiac myocytes) have marginal renewal capacity

Question 14

describe the extent of injury

Answer 14

The magnitude of injury may exceed regeneration capacity

Question 15

describe the underlying disease determinant

Answer 15

May impair proliferative response or remodeling (ex: diabetes)

Question 16

describe the Presence or absence of ongoing inflammation

Answer 16

Due to concurrent infection or other factors, continued release inflammatory mediators may disrupt balance toward repair

Question 17

what are the three key growth factors that regulate fibrosis.

Answer 17

PDGF, TGFb, & FGF-2

Question 18

describe PDGF

Answer 18

1. Platelet-derived growth factor
2. Migration and proliferation of fibroblasts, smooth muscle cells, and macrophages

Question 19

describe TGFb

Answer 19

1. Transforming growth factor
2. Potent fibrogenic factor that stimulates collagen, fibronectin, and proteoglycan synthesis
3. Inhibits collagen degradation
4. Inhibits lymphocyte proliferation
5. Has anti-inflammatory effect

Question 20

describe FGF-2

Answer 20

1. Fibroblast growth factor
2. Stimulates proliferation of endothelial cells
3. Promotes migration of macrophages and fibroblasts to damaged areas