TISSUE REPAIR

Question 1

Identify this pathologic repair process

accumulation of excessive amounts of collagen

remain within the confines of the original wound.

May regress spontaneously

Bundles of collagen fibers lie in a parallel arrangement

Answer 1

Hypertrophic scar

Question 2

Identify this pathologic repair process

scar tissue grows beyond the boundaries of the original wound

Does not regress

Bundles of collagen fibers lie in a disorganized fashion

Frequently recurs after excision

Answer 2

Keloid

Question 3

List 2 examples of stable tissues

Answer 3

parenchyma of liver, kidney, and pancreas

endothelial cells, fibroblasts, and smooth muscle cells

Question 4

Which type of tissues/cells best fits the description given below?

can readily regenerate after injury as long as the pool of stem cells is preserved

Answer 4

Labile (continuously dividing) tissues

Question 5

Special stain to demonstrate collagen

Answer 5

Masson’s Trichrome stain

Question 6

See attached image. What is the underlying basis?

Answer 6

Exaggerated wound contraction

Question 7

2 major mechanisms of liver regeneration

Answer 7

1. Proliferation of residual hepatocytes
2. Repopulation from progenitor cells

Question 8

Name the localized tumor resulting from proliferation of fibroblasts, with very low metastatic potential

Answer 8

Desmoids (aggressive fibromatoses)

Question 9

List 1 word that best fits the description given below:

Fibrosis that develops in a tissue space occupied by an inflammatory exudate

Answer 9

Organization

Question 10

Which type of tissues/cells best fits the description given below?

Inability to proliferate in response to injury; terminally differentiated

Answer 10

Permanent tissues

Question 11

Which type of tissues/cells best fits the description given below?

minimal proliferative activity in their normal state but capable of dividing in response to injury or loss of tissue mass

Answer 11

Stable tissues

Question 12

List 3 examples of permanent tissues

Answer 12

1. Neurons
2. Cardiac myocytes
3. Skeletal muscle cells

Question 13

See the attached image and identify the abnormal pathologic repair process

Answer 13

Exuberant granulation (proud flesh)

Question 14

Two mechanisms via which repair occurs

Answer 14

1. Regeneration
2. Scar (connective tissue deposition) formation

Question 15

List 3 examples of labile tissues

Answer 15

Bone marrow

Skin

GI tract

Question 16

3 key differences between hypertrophic scars and keloids

Answer 16

Question 17

Identify the pathologic repair process shown in the attached image

Etiologic basis ?

Answer 17

Wound dehiscence

Secondary to mechanical stress - Vomiting, coughing, or ileus

Question 18

Most important mediator of fibrosis

Answer 18

TGF-beta

Question 19

List 6 key differences between healing by first and second intention

Answer 19

See attached table

Question 20

By when does wound strength reaches approximately 70% to 80% of normal?

Answer 20

Month 3

Question 21

By when does the wound acquire tensile strength approximately 10% of that of unwounded skin?

Answer 21

End of week 1

Question 22

Identify the timeline during which the following events are likely to occur in wound healing

increasing collagen deposition, regression of vessels, edema and leukocytic infiltrate

Answer 22

Week 2

Question 23

Identify the timeline during which the following event is likely to occur in wound healing

granulation tissue formation is at its peak

Answer 23

Day 5

Question 24

List 1 example of healing by first intention

Answer 24

healing of a clean, uninfected surgical incision approximated by surgical sutures

Question 25

List examples of healing by second intention

Answer 25

large wounds, abscesses, ulceration, and ischemic necrosis (infarction) in parenchymal organs

Question 26

How does zinc deficiency impair wound healing?

Answer 26

Zinc: ↑type III collagen; ↓tensile strength

Question 27

How does copper deficiency impair wound healing?

Answer 27

↓Copper: ↓cross-linking of collagen

Question 28

How does Vitamin C deficiency impair wound healing?

Answer 28

structurally weakened collagen due to lack of Vit C for hydroxylation of proline and lysyl residues and no cross linking

Question 29

How does corticosteroid administration affect wound healing?

Answer 29

Glucocorticoids --\> inhibition of TGF-β production ----\>decreased fibrosis and collagen production ----\>weak scar

Question 30

1. Identify this key event of the wound healing process 2. When does it begin? 3. When does it reach its peak?

Answer 30

1. Granulation tissue 2. Day 3 3. Day 5

Question 31

Microscopic appearance of granulation tissue

Answer 31

proliferation of fibroblasts and new thin-walled, delicate capillaries (angiogenesis), in a loose extracellular matrix, with admixed inflammatory cells, mainly macrophages

Question 32

List 3 actions of TGF-beta in scar formation

Answer 32

1. stimulates fibroblast migration and proliferation 2. increased synthesis of collagen and fibronectin 3. decreased degradation of ECM due to inhibition of metalloproteinases

Question 33

Which pathway ensures proper patterning of the newly formed vessels in angiogenesis?

Answer 33

Notch pathway

Question 34

List 4 mediators of angiogenesis

Answer 34

VEGF FGF PDGF TGF-beta

Question 35

Role of VEGF in angiogenesis

Answer 35

1. promotes vasodilation by stimulating the production of NO 2. stimulates survival, migration and proliferation of endothelial cells

Question 36

First step in the tissue repair process

Answer 36

Formation of a fibrin clot

Question 37

What is the basis for the formation of contractures?

Answer 37

**Excessive MMP activation** - encourages migration of myofibroblasts at wound edges and scar tissue remodelling