Tissue Renewal, repair, and regeneration - 28 (Svesson)

Question 1

1. Differentiate tissue regeneration and tissue repair.

Answer 1

a Tissue regeneration is the process of replicating the same tissues that were previously there before damage. It will have the same size number and no damage is present
b Tissue repair is replacing the cells that have been damaged but with a different type of tissue and scarring is present

Question 2

2. State the 4 stages of healing after tissue injury.

Answer 2

a Hemostasis
i This happens within minutes of tissue injury and the red blood cells set up a barrier essentially to stop from losing more blood
b Inflammation
i Happens within hours of injury this professes is driven by platelet derived mediators, bacteria, and secreted chemoattractant
c Proliferation
i This happens days after infection. It is mediated by macrophages and fibroblast derived growth factors
d Remodeling
i Weeks to months after infection. Transition type III to type I collagen restoring tensile strength of tissue

Question 3

3. Identify the determinants of regeneration versus repair after tissue injury.

Answer 3

a In regeneration T regulatory cells are recruited to decrease chronic inflammation whereas in tissue repair continuous damage and scaring is happening because of continued activation of inflammatory cells
b Also involved the nature of the injury because some cells don’t have the ability to do tissue regeneration
c Extent of injury if the injury is too big regeneration is not possible
d Also inflammation like stated earlier
e Finally underlying diseases can impair proliferation responses an example is diabetes

Question 4

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

Answer 4

a Change in gene expression

Question 5

5. Describe the two forms of ECM and their key components.

Answer 5

a Interstitial matrix
b Basements membrane

Question 6

6. Identify the three key growth factors that regulate fibrosis.

Answer 6

a PDGF
i Proliferation and migration of macrophages, fibroblasts, and smooth muscle cells
b TGF beta
i Stimulates fibronectin and proteoglycan synthesis
ii Inhibits lymphocyte proliferation
c FGF-2
i Stimulates proliferation
ii Promotes migration of macrophages and fibroblasts