wound healing Flashcards

1
Q

skin protects against

A

UV
mechanical stress
chemicals
thermal insult
dehydration
pathogens

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2
Q

skin is used to sense

A

touch
pressure
heat

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3
Q

layers of skin

A

epidermis
dermis
hypodermis

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4
Q

the epidermis is ___ in origin

A

ectodermal

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5
Q

what cells make up the epidermis?

A

keratinocytes, langerhan cells and melanocytes

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6
Q

the thickness of the epidermis is inversely proportional to ___

A

hair covering

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7
Q

___ gives the epidermis a semi-permeable/protective barrier

A

keratin

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8
Q

which layer of the skin is avascular

A

epidermis

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9
Q

hair follicles, nails and sweat glands are in what part of the skin?

A

epidermis
invaginations of the epidermis into the dermis

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10
Q

dermis is composed largely of ___

A

dense irregular and loose connective tissue
collagen and elastic fiber
GAGs

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11
Q

what type of cells are found in the dermis

A

fibroblasts
adipocytes
vasculature and lymphatics
nerve endings
mast cells and histiocytes

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12
Q

hypodermis is made of ___ muscle

A

panniculus carnosus

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13
Q

where do you find the stratum adiposum subcutis

A

hypodermis

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14
Q

what are the 3 interconnected levels of cutaneous circulation

A

subdermal (subcutaneous plexus)- deep
cutaneous- middle
subpapillary- superficial

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15
Q

what is different between the blood supply for skin of a dog vs a primate

A

dermis supplied by parallel musculocutaneous arteries and veins

hypodermis supplied by direct cutaneous artery and vein

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16
Q

direct cutaneous artery and vein is found

A

superficial and deep to panniculus muscle and in the hypodermis of cats and dogs

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17
Q

the direct cutaneous artery and vein supply

A

the deep or subdermal plexus
superficial or deep to panniculus muscle

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18
Q

cutaneous plexus is found ___

A

in the dermis
formed from branches of the deep (subdermal plexus)
gives rise to the superficial plexus

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19
Q
A
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20
Q

___ is the major vascular network in skin of dogs and cats

A

deep/subdermal plexus

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21
Q

___ extends capillary loops to nourish the epidermis

A

superficial plexus

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22
Q

During dissection, to elevate the skin and preserve cutaneous vasculature, you must go between the ____ and the ___

A

subdermal plexus/ panniculus m.

underlying skeletal muscle

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23
Q

3 stages of healing

A

inflammation/debridement
repair / proliferation
maturation/ remodeling

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24
Q

Immediately after injury, ___ fills the wound and cleans the wound surface

A

hemorrhage

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25
Q

blood clot/ scab formation provides a ___, ___ wound edges and provides the substrate for ___

A

hemostatic plus, immediate barrier to infection and fluid loss

stabilizes wound edges

early reorganization of the wound (scaffold)

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26
Q

vascular phase initially starts with ___ then followed by ___ with recruitment of plasma and leukocytes

A

vasoconstriction
vasodilation

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27
Q

cellular/debridement phase starts ___ after injury

A

6ish hours

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28
Q

what cells in the cellular phase

A

lymphocytes and PMNs
monocytes/macrophages
platelets
mast cell and eosinophils

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29
Q

___ come during the inflammatory phase and concentrate at the site of injury to remove cellular debris and bacteria

A

lymphocytes and PMNs

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30
Q

what do macrophages do

A

eat cell debris

secrete chemoattractants and growth factors and cytokines (PDGF, VEGF)

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31
Q

___ induces vasoconstriction, platelet and neutrophil aggregation

A

Thromboxane A2

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32
Q

___ influence angiogenesis and fibroblast activity

A

mast cells

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33
Q

eosinophils mediate ___ and ___

A

angiogenesis and epithelial migration

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34
Q

___ is considered the lag phase of wound repair

A

initial (inflammation/debridement)

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35
Q

rapid increase in wound strength from collagen happens in the ____

A

first 3-5 days

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36
Q

3 main events of repair/proliferative phase

A

granulation tissue formation
wound contraction
epithelialization

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37
Q

granulation tissues appears ___ at a rate of ___

A

3-5 days post injury
0.4-1 mm per day

38
Q

granulation tissue will help healing by ___

A

protect the wound, provide a barrier to infection and act as a scaffold for epithelial migration

39
Q

fibroblast produce ECM in a process called ___

A

fibroplasia

40
Q

fibroblasts come from ___

A

local and distant sites
(can be from bone marrow→ myeloid cells)

41
Q

fibroblasts migrate along ___

A

fibrin strands

42
Q

___ produce ECM and cytokines and growth factors

A

fibroblasts

43
Q

fibrin, fibronectin and hyaluronic acid will facilitate aggregation and orientation of___ and ___

A

collagen
growth of capillary buds (neovascularization)

44
Q

what type of collagen is laid down first?

A

type III, then replaced by type I

45
Q

greatest accumulation of collagen occurs when in healing?

A

7-14 days post injury

46
Q

which growth factor is important for angiogenesis initially?

A

bFGF (first 3 days)

VEGF more important 4-7 days

47
Q

which growth factor is important for angiogenesis at 4-7 days

A

VEGF

bFGF - 1-3 days

48
Q

___, ___ and ___ are important mediators for angiogensis

A

growth factors and cytokines (bFGF, VEGF)

low O2

high lactate

49
Q

initially capillary loops are open but become ___

A

closed arcades

50
Q

wound contraction happens ___ post injury

A

full thicken skin advanced (no new skin formed)
5-9 days post injury
tension and shape determine how well it can move

51
Q

how does wound contraction happen

A

fibroblasts grab onto collagen and pull- consolidate collagen in the wound center

myofibroblast grab onto skin and contract pulling the skin with them

52
Q

___ requires new skin synthesis by keratinocytes

A

wound epithelialization

53
Q

Within 24 hours of wounding, ____ from the wound margins begin to cover the wound

A

keratinocytes
(wound epithelization)

54
Q

what stage of wound healing requires more O2

A

wound epithelization

energy dependent and positively related to oxygen tension

55
Q

wound epithelization is faster or slower under moist wound healing conditions

A

slower

56
Q

wound epithelization advances from ____ structures in partial thickness wound

A

adnexal

contains stem cells that speed up healing

57
Q

what happens during maturation and remodelling phase

A

scab sloughs
maturation of collagen fibers
remodellling

58
Q

a wound will reach ___ % of its original strength

A

70-80

59
Q

cats or dogs heal faster?

A

dogs - will have more granulation tissue, greater wound epithelialization and wound contraction

60
Q

ponies or horses heal better?

A

ponies

horses lead to proud flesh (EGT- exuberant granulation tissue)

61
Q

contracture

A

contraction that results in problem

closes off opening or can’t move

62
Q

5 wound assessment
type of ___
___of wound
degree of ___
tissue ___
___ of wound

A

type of trauma
age of wound
degree of contamination
tissue viability
location of wound

63
Q

a clean wound

A

controlled aseptic environment
surgical incision

64
Q

clean contaminated wound

A

contaminated area entered but no spillage
example: enterotomy

65
Q

contaminated wound

A

most common
road rash, traumatic wound
acute inflammation with NO pus

66
Q

dirty wound

A

pus, abscess, delayed treatment of traumatic wound

67
Q

Contaminated wounds must be converted into ___ prior to closure (if immediate closure is not possible, open wound management will be necessary)

A

clean wounds -> surgical incision

68
Q

___ will remove foreign debris and contaminants with large volume of warm fluids

A

lavage- hydrodynamic debridement

69
Q

___ are used for lavage

A

balanced electrolyte solution
sterile saline
chlorhexidine (0.05%)
povidone- idodine (0.1-1%)

70
Q

___ is accomplished by maintaining a moist wound environment

A

autolytic wound debridement

71
Q

3 types of autolytic wound debridement

A

hydrophilic
occlusive
semiocclusive

exudate or wound fluid that contains enzymes and growth factors remain in contact with the wound

72
Q

when a wound is too moist

A

maceration

73
Q

___ are chemical enzymes that slough necrotic tissue

A

enzymatic wound debridement

can be nonselective

74
Q

mechanical debridement

A

wet to dry
outdated
dries and rips off bad tissue

75
Q

___ combines mechanical and autolytic debridement

A

hypertonic saline bandage
for moderate/high exudate, infected or necrotic wounds

76
Q

maggot therapy

A

biosurgical debridement
removes necrotic tissue

77
Q

systemic antimicrobials should be used ___

A

High risk of bacteremia or sepsis
* Prophylactic or therapeutic
* Prolonged use contraindicated

78
Q

topical antimicrobials will enhance __ and may delay ___ formation

A

epithelization
granulation tissue

79
Q

vacc bandage also called

A

negative pressure wound therapy

80
Q

what do NPWT help with

A

negative pressure wound therapy (vacc bandage)

Decreases edema
* Decreases bacterial colonization
* Increases granulation tissue
* Increases local blood flow
* Enhanced epithelial migration
* Accelerates wound closure

81
Q

when not to use a NPWT

A

negative pressure wound therapy

Malignancy in wound
– Untreated osteomyelitis
– Non-enteric or unexplored fistula
– Necrotic tissue with eschar present
– Exposed blood vessels or organs

82
Q

4 types of moisture balancing dressings

A

calcium alginate- high exudate
polyurethane foam- moderate to high exudate
hydrocolloids- low to moderate
hydrogels- low to none

83
Q

primary closure happens with in ___

A

24 hours

84
Q

delayed primary closure happens within ___

A

2-5 days
before granulation tissue

85
Q

secondary closure happens within

A

> 5 days, after granulation tissue

86
Q

second intention healing

A

wound the healed on its own

87
Q

Epidermis (ectodermal origin)
Composed of several layers of cells called___ that are undergoing a process of differentiation.

A

keratinocytes

88
Q

The dermis is composed of ___, reticular (precollagen), and elastic fibers surrounded by a mucopolysaccharide ground substance (hyaluronic acid and chondroitin sulfate.

A

collagen

89
Q

In dogs and cats, the hypodermis is made up of two distinct layers of fat (stratum adiposum subcutis) and ___

A

muscle (panniculus carnosus muscle).

90
Q

This ___ is composed of the cutaneous trunci, platysma, sphincter coli superficialis, sphincter colli profundus, preputialis, and supramammarius muscles.

A

panniculus muscle

91
Q

cutaneous circulation

A

Subdermal or subcutaneous plexus (Deep)-the major vascular network to the skin. In regions of skin where a panniculus muscle is present, the subdermal plexus lies both superficial and deep to it.

cutaneous (middle) plexus.

subpapillary (superficial) plexus which supplies the superficial dermis and extends capillary loops to nourish the epidermis (these loops are poorly developed in the dog and cats in comparison to primates and pigs).

92
Q

In areas of the body where the panniculus is present, the surgeon must ___ to preserve the vital subdermal plexus.

A

undermine the fascial plane beneath the cutaneous musculature