Wound healing - Tesse

Question 1

Explain the role of skin

Answer 1

1. structure and protection
2. homeostasis and regulation
3. sensation

Question 2

What are two examples of abnormal response to skin wounding

Answer 2

ulceration, excess scar

Question 3

what are normal responses to wounds

Answer 3

epidermal barrier restoration (epithelialization) and dermal barrier restoration (fibroblast proliferation)

Question 4

What are the 4 stages of wound healing

Answer 4

1. inflammation
2. debridement
3. repair
4. maturation

Question 5

What is the first stage of wound healin

Answer 5

inflammation
- early/vascular
-late/cellular

Question 6

what is the second stage of wound healing

Answer 6

debridement

Question 7

what is the third stage of wound healing

Answer 7

repair
- fibroplasia
- angiogenesis
-epithelialization
-contraction

Question 8

What is the fourth stage of wound healing

Answer 8

maturation
-tissue remodelling

Question 9

What stage of wound healing is medical intervention most effective?

Answer 9

inflammatory stage

Question 10

how long is the inflammatory stage

Answer 10

0-3 days

Question 11

what are the two phases of inflammatory stage

Answer 11

Vascular and cellular

Question 12

Describe the vascular phase of the inflammatory response

Answer 12

1. bleeding to clean wound bed
2. immediate vasoconstriction (epinephrine response, vascular smooth muscle response)
3. vasodilation ( 5 -10 minutes later, leakage of fibrinogen and clotting factors, cellular infiltration begins)

Question 13

describe the cellular phase of the inflammatory response

Answer 13

-clot formation and establishment of scaffold
- fibrinogen > fibrin
- fibrin and plasmin plug lymphatics
- clot dries into a scab

Question 14

what initiates stage 2 of wound repair

Answer 14

WBCs under scab

Question 15

When does debridement start?

Answer 15

6 hours after wounding, peaks around day 2-3

Question 16

What are the first responders to the scene during debridement

Answer 16

Neutrophils

Question 17

what enzymes do neutrophils release during debridement

Answer 17

collagenase and elastase

Question 18

what do neutrophils release to attract monocytes and fibroblasts

Answer 18

chemoattractant cytokines

Question 19

which are essential to non-infected wounds: neutrophils or monocytes

Answer 19

monocytes

Question 20

when do monocytes arrive?

Answer 20

12 hours in

Question 21

what are three things that monocytes are essential for during debridement

Answer 21

1. collagenase production
2. phagocytic actions
3. release growth factors and cytokines

Question 22

Cellular infiltration begins during

Answer 22

debridement stage

Question 23

what stage does exudate arise

Answer 23

debridement

Question 24

What calls in the mesenchymal monocytes and keratinocytes that results in epithelialization

Answer 24

macrophages

Question 25

What is “PRP”

Answer 25

platelet-rich plasma that can be injected into a patient to enhance wound healing

Question 26

when do lymphocytes come into play

Answer 26

approx 1 week after wounding. Less numerous than macrophages.

Question 27

what makes up wound exudate

Answer 27

dead cells, wbcs, tissue, protein, fluid.

Question 28

When does the repair stage begin

Answer 28

day 3-5

Question 29

what stage does proliferation of new tissue start

Answer 29

repair stage

Question 30

what are four things that happen during stage 3 of wound repair

Answer 30

1. fibroplasia (fibroblast proliferation)
2. angiogenesis
3. epithelialization
4. wound contraction by development of myofibroblasts

Question 31

When does fibroplasia begin

Answer 31

starts day 3-4, continues for 2-4 weeks

Question 32

Describe fibroplasia

Answer 32

fibroblasts migrate from surrounding tissue. Mesenchymal cells proliferate in wound and migrate along fibrin strands in clot. Fibroblasts become myofibroblasts, develop cytoskeletal contractile elements. wound fibroblasts produce type 3 collagen, type 1 pro-collagen, ECM components.

Question 33

What is the end result of fibroplasia

Answer 33

the fibrin filled wound becomes a connective tissue filled wound

Question 34

Describe angiogenesis

Answer 34

new capillaries grow into wound, attracted by tissue hypoxia.

Question 35

T/F: granulation tissue is low in blood flow, but high in innervation

Answer 35

false. it is high in blood flow, low in innervation.

Question 36

What is granulation tissue

Answer 36

healing tissue composed of newly vascularized ECM, inflammatory cells, fibroblasts, matrix components

Question 37

what are the five processes that occur during the repair stage

Answer 37

1. fibroplasia
2. angiogenesis
3. granulation tissue formation
4. epithelialization
5. contraction

Question 38

what are some purposes of granulation tissue

Answer 38

• resistant to infection
• provides surface for epithelial migration
• role in wound contracture

Question 39

what type of collagen is most common in wounds

Answer 39

type 3

Question 40

What is “proud flesh”

Answer 40

excessive granulation tissue that becomes irregular, grows above skin edge, and interferes with contraction and epithelialization

Question 41

where does epithelialization begin

Answer 41

at the wound margin. requires granulation surface in open wounds. Stops with contact inhibition

Question 42

what heals faster: a dry wound or a moist wound? Why?

Answer 42

a moist wound. This is because O2 is more available. Moist wounds heal 50% faster

Question 43

What is contraction simultaneous with

Answer 43

granulation and epithelialization

Question 44

what changes phenotype during contraction phase?

Answer 44

fibroblasts become myofibroblasts so that they can contract

Question 45

what is myofibroblast persistence?

Answer 45

pathologic tissue development, excessive contracture, fibrosis, disfigurement

Question 46

what are the three phases of wound contraction

Answer 46

1. lag phase
2. rapid contraction phase
3. slow contraction phase

Question 47

what is the lag phase of wound contraction

Answer 47

wound increases in size due to swelling, movement, etc. lasts 5-10 days

Question 48

how long does the rapid contraction phase last

Answer 48

10-14 days

Question 49

what is the slow contraction phase

Answer 49

follows complete epithelialization. gradual change of myofibroblasts returning to fibroblasts. begins after 2+ weeks

Question 50

The only layer contracting during the wound contraction phase is the

Answer 50

epidermis, NOT the dermis. adnexal structures therefore do NOT return, as they are part of the dermis.

Question 51

what is contact inhibition

Answer 51

growth of cells until they touch another cell

Question 52

What is involved with the maturation stage of wound healing

Answer 52

deposition, reorganization, and rearrangement of collagen fibers. The cell population matures, so myofibroblasts revert to normal fibroblasts.

Question 53

maturation changes the ___

Answer 53

ECM. Type 3 collagen is replaced by type 1, increased cross-linking, and reorganization along lines of tension

Question 54

T/F: the gain in mechanical strength of tissue during maturation is slow

Answer 54

true. most rapid between 7-14 days, 20% normal at 3 weeks, and 80-85% of normal at final result. will never return to original tensile strength of uninjured tissue.