Path - Inflammation (Free radical injury, Inhalational injury, Scar formation, & Wound healing)

Question 1

What are 3 ways in which free radicals damage cells?

Answer 1

Free radicals damage cells via (1) membrane lipid peroxidation, (2) protein modification, and (3) DNA breakage

Question 2

What are 6 processes that initiate free radical injury?

Answer 2

Initiated via (1) radiation exposure (e.g., cancer therapy) (2) metabolism of drugs (phase I) (3) redox reactions (4) nitric oxide (5) transition metals (6) leukocyte oxidative burst

Question 3

What are 3 ways by which free radicals can be eliminated/?

Answer 3

Free radicals can be eliminated by (1) enzymes (e.g., catalase, superoxide dismutase, glutathione peroxidase) (2) spontaneous decay (3) antioxidants (e.g., vitamins, A, C, E)

Question 4

Give 3 examples of enzymes that eliminate free radicals.

Answer 4

(1) catalase (2) superoxide dismutase (3) glutathione peroxidase

Question 5

Give 3 examples of antioxidants that eliminate free radicals.

Answer 5

(1) vitamin A (2) vitamin C (3) vitamin E

Question 6

What are 6 pathologies associated with free radical injury?

Answer 6

Pathologies include: (1) Retinopathy of prematurity (2) Brochopulmonary dysplasia (3) Carbon tetrachloride, leading to liver necrosis (fatty change) (4) Acetaminophen overdose (fulminant hepatitis, renal papillary necrosis) (5) Iron overload (hemochromatosis) (6) Reperfusion injury (e.g., superoxide), especially after thrombolytic therapy

Question 7

What is the most common pulmonary complication after exposure to fire?

Answer 7

Inhalational injury

Question 8

Products of what process cause inhalational injury? Give 2 examples.

Answer 8

Inhalation of products of combustion (e.g., carbon particles, toxic fumes)

Question 9

Again, Products of what process cause inhalational injury? Give 2 examples. What are 3 pathologies/complications that may result?

Answer 9

Inhalation of products of combustion (e.g., carbon particles, toxic fumes) –> chemical treacheobronchitis, edema, and pneumonia

Question 10

How much tensile strength returns following wound, and after how long?

Answer 10

70-80% tensile strength returns at 3 months following wound; little additional tensile strength will be regained

Question 11

What are the 2 common pathologic types of scar formation?

Answer 11

(1) Hypertrophic scars (2) Keloid scars

Question 12

Compare/Contrast the collagen synthesis of hypertrophic versus keloid scars.

Answer 12

HYPERTROPHIC - High/Increased; KELOID - Extremely High/Increased

Question 13

Compare/Contrast the collagen arrangement of hypertrophic versus keloid scars.

Answer 13

HYPERTROPHIC - Parallel; KELOID - Disorganized

Question 14

Compare/Contrast the extent of hypertrophic versus keloid scars.

Answer 14

HYPERTROPHIC - Confined to borders of original wound; KELOID - Extend beyond borders of original wound

Question 15

Compare/Contrast the recurrence of hypertrophic versus keloid scars.

Answer 15

HYPERTROPHIC - Infrequently recur following resection; KELOID - Frequently recur following resection

Question 16

Name 5 tissue mediators of wound healing.

Answer 16

(1) PDGF (2) FGF (3) EGF (4) TGF-Beta (5) Metalloproteinases

Question 17

What secretes PDGF?

Answer 17

Secreted by activated platelets and macrophages

Question 18

What are 2 major roles of PDGF in wound healing?

Answer 18

(1) Induces vascular remodeling and smooth muscle cell migration (2) Stimulates fibroblast growth for collagen synthesis

Question 19

What is the role of FGF in wound healing?

Answer 19

Stimulates all aspects of angiogenesis

Question 20

What is the role of EGF in wound healing? Give a specific example of its mechanism and the associated gene.

Answer 20

Stimulates cell growth via tyrosine kinases (e.g., EGFR, as expressed by ERBB2)

Question 21

What are 3 major roles of TGF-Beta in wound healing?

Answer 21

(1) Angiogenesis (2) Fibrosis (3) Cell cycle arrest

Question 22

What is the role of metalloproteinases in wound healing?

Answer 22

Tissue remodeling

Question 23

What are 3 main phases of wound healing? What is the time frame of each?

Answer 23

(1) Inflammatory (immediate) (2) Proliferative (2-3 days after wound) (3) Remodeling (1 week after wound)

Question 24

What are the 3 mediators of the inflammatory phase of wound healing? Again, what is its time frame?

Answer 24

Platelets, neutrophils, macrophages; Immediate

Question 25

What are the 5 mediators of the proliferative phase of wound healing)? Again, what is its time frame?

Answer 25

Fibroblasts, myofibroblasts, endothelial cells, keratinocytes, macrophages; 2-3 days after wound

Question 26

What is the mediator of the remodeling phase of wound healing? Again, what is its time frame?

Answer 26

Fibroblasts; 1 week after wound

Question 27

What 3 major events occur during the inflammatory phase of wound healing?

Answer 27

(1) Clot formation (2) Increased vessel permeability and neutrophil migration into tissue (3) Macrophages clear debris 2 days later

Question 28

What cells clear debris in the wound healing process? During which phase does this occur, and when?

Answer 28

Macrophages clear debris 2 days later (following clot formation, increased vessel permeability & neutrophil migration into tissue)

Question 29

What 5 major events occur during the proliferative phase of wound healing?

Answer 29

(1) Deposition of granulation tissue and collagen (2) Angiogenesis (3) Epithelial cell proliferation (4) Dissolution of clot (5) Wound contraction (mediated by myofibroblasts)

Question 30

What mediates wound contraction? During which phase of wound healing does this occur?

Answer 30

Wound contraction (mediated by myofibroblasts); Proliferative phase

Question 31

What major event occurs during remodeling phase of wound healing, and what effect does this have?

Answer 31

Type III collagen replaced by type I collagen, increasing tensile strength of tissue