Wound Healing

Question 1

Three phases of wound healing?

Answer 1

1. Inflammatory
2. proliferative
3. remodeling

Question 2

How long does the inflammatory phase last?

Answer 2

3 to 5 days

Question 3

Role of the fibrin clot

Answer 3

Secures hemostasis, matrix for cells to migrate during repair, reservoir of cytokines and growth factors released as activated platelets degranulate

Question 4

First white blood cells to enter would

Answer 4

Neutrophils arrive at wound site within minutes

Question 5

Second white blood cells to enter wound

Answer 5

Macrophages, continue micro debridement and release growth factors

Question 6

How long does proliferative phase last?

Answer 6

Starts as early as day 3 and lasting up to 3 weeks

Question 7

First collagen to be deposited in a healing wound?

Answer 7

Type III collagen, immature

Synthesized by fibroblasts

Question 8

What happens during proliferative phase?

Answer 8

Angiogenesis
Formation of immature collagen
Epithelialization

Question 9

What happens during inflammatory phase?

Answer 9

Formation of fibrin clot
Hemostasis
Release of growth factors
Micro debridement

Question 10

Strength of healed wound with scar tissue

Answer 10

80% of original strength

Question 11

How long does remodeling phase last?

Answer 11

Starting at three weeks to several years

Question 12

What type of collagen forms as remodeling remodeling phase progresses?

Answer 12

Stronger type I collagen

Question 13

Regeneration rate for peripheral nerves

Answer 13

1 mm per day

Question 14

Describe the term for what happens to the distal nerve segment after severance

Answer 14

Wallerian degeneration.

Injured axons break up and are phagocytized by Schwann cells and macrophages

Question 15

Indirect bone healing involves formation of what?

Answer 15

A callus that acts as a splint

Question 16

Two types of direct bone healing

Answer 16

Gap healing
Contact healing
(No callus formation)

Question 17

Type of bone deposited in healing contact zones

Answer 17

Lamellar bone

Question 18

Type of bone deposited in healing gaps

Answer 18

Fibrous tissue, fibrocartilage, and woven bone

Question 19

How long until radiographic evidence of bone formation is evident after extraction?

Answer 19

4 to 6 months

Question 20

What has a greater survival rate, full thickness or split thickness skin graft?

Answer 20

Split thickness grafts have greater survival rates clinically. Full thickness grafts are slower to revascularize, but less susceptible to trauma.

Question 21

Number of organisms required for wound infection

Answer 21

100,000 organisms per gram of tissue

Question 22

Characteristics of hypertrophic scars

Answer 22

Arise shortly after injury.
Circumscribed within the boundaries of the wound.
Eventually recede.

Question 23

Characteristics of keloids

Answer 23

Months after injury.
Grow beyond wound boundaries.
Rarely subside.

Question 24

Treatment of keloids?

Answer 24

Injection of corticosteroids to inhibit protein synthesis

Question 25

How long does peripheral vasoconstriction from smoking a cigarette last?

Answer 25

Can last up to an hour, a ppd smoker is tissue hypoxia for most parts of the day

Question 26

Effects of HBO on wounds

Answer 26

Increases the quantity of dissolved oxygen and the driving pressure for oxygen diffusion into the tissue.

Stimulates growth of fibroblasts and vascular endothelial cells, increases tissue vascularization, enhances killing ability of leukocytes, lethal for anaerobic bacteria.

Question 27

Key amino acid in wound healing

Answer 27

Methionine

Question 28

Half-life of serum pre-albumin versus albumin

Answer 28

Pre-albumin half-life of 2 days

Albumin half-life of 20 days

Question 29

Normal serum prealbumin

Answer 29

22.5 mg/dL
<17 mild deficit
<11 severe deficit

Question 30

Mechanism of rhBMP-2

Answer 30

Induce undifferentiated mesenchymal cells to differentiate into osteoblasts (osteoinduction)