Healing/Repair

Question 1

Regeneration

Answer 1

Replacement of damaged cells by replicating cells of the same type
Connective tissue framework remains intact (serves as scaffolding)

Question 2

Scar formation

Answer 2

Replacement by connective tissue

Question 3

Extracellular matrix

Answer 3

Interstitial matrix and basement matrix
Fibrous structural proteins: collagens, elastins
Water hydrated gels: proteoglycans, hyaluronan
Adhesive glycoproteins

Question 4

Labile tissues

Answer 4

Continuously dividing
Ex: Hematopoietic cells of bone marrow
Squamous epithelium of skin, oral cavity
Columnar epithelium of GI tract

Question 5

Stable tissues

Answer 5

No level of replication (G0 cell cycle)
Rapidly divide when stimulated
Ex: liver, kidney, pancreas, smooth muscle cells, fibroblasts

Question 6

Epidermal Growth Factor (EGF)

Answer 6

Sources: activated macrophages, keratinocytes
Functions: mitogenic for keratinocytes, fibroblasts; stimulates keratinocyte migration

Question 7

Transforming Growth Factor alpha (TGF-a)

Answer 7

Sources: activated macrophages, keratinocytes
Functions: stimulates proliferation of hepatocytes, other epithelial cells

Question 8

Vascular Endothelial Growth Factor (VEGF)

Answer 8

Sources: mesenchymal cells
Functions: stimulates proliferation of endothelial cells; increases vascular permeability

Question 9

Platelet-Derived Growth Factor (PDGF)

Answer 9

Sources: platelets, macrophages, endothelial cells, smooth muscle cells, keratinocytes
Functions: chemotactic; activated and stimulates proliferation of fibroblasts, endothelial cells; stimulates ECM protein synthesis

Question 10

Fibroblast Growth Factors (FGFs)

Answer 10

Sources: macrophages, mast cells, endothelial cells

Functions; chemotactic, mitogenic for fibroblasts; stimulates angiogensis, ECM protein synthesis

Question 11

Transforming Growth Factor beta (TGF-b)

Answer 11

Sources: platelets, macrophages, endotehlial cells, fibroblasts
Functions: chemotactic for leukocytes, fibroblasts; stimulates ECM synthesis; suppresses acute inflammation

Question 12

Granulation tissue

Answer 12

Specialized tissue that fills in defect in organs when non-regenerative cells and/or connective tissue framework is destroyed

Question 13

Organization

Answer 13

Process of transforming granulation tissue into a dense scar (blood vessels are less prominent, type III collage is replaced by type I)

Question 14

Healing by First Intention

Answer 14

Clean, uninfected surgical incision approximated by surgical sutures
Epithelial regeneration principle mechanism of repair
Minimal contraction of wound

Question 15

Healing by Second Intention

Answer 15

Large skin wound, extensive destruction, contamination, infection
Larger clot, more intense inflammation
Wound granulates in without closing gap with sutures
Wound contraction by microfibroblasts

Question 16

Fibrosis

Answer 16

Excessive deposition of collagen and other ECM components in a tissue
TGF-b can drive fibrosis

Question 17

Vitamin C

Answer 17

Function: cofactor for hydroxylation reactions (cross-linking of lysine and proline in collagen sythesis)
Deficiency: scurvy, impaired wound healing, blood vessel fragility
Basis of deficiency: diets lacking fruits and vegetables

Question 18

ZInc

Answer 18

Function: cofactor for metalloenzymes (collagenase)
Deficiency: poor wound healing, growth impairment
Basis of deficiency: inadequate intake, alcoholism, chronic diarrhea, and inflammatory disease

Question 19

Copper

Answer 19

Function: cofactor for lysyl oxidase, cross-links lysine and hydroxylysine
Deficiency: abnormal collagen cross-linking, poor wound healing, muscle weakness, neurologic deficits
Basis of deficiency: usually due to total parenteral nutrition