Skin and Wound healing Flashcards
1
Q
How much resting cardiac output does the skin receive?
A
1/3 resting cardiac output
2
Q
What gives skin its color?
A
Melanocytes which contain melanin found mostly in the basal layer of the epidermis
3
Q
What causes different shades of skin?
A
Size and activity of melanocytes
4
Q
What are melanocytes?
A
contain melanin that protect & give skin its color
5
Q
What are Merkel cells?
A
light touch sensation cells
6
Q
What are Langerhans cells?
A
infection fighting cells
7
Q
Where are the epidermal appendages housed?
A
in the dermis and move through the epidermis
8
Q
What are the epidermal appendages?
A
hair and sebaceous (oil secreting) & sudoriferous (sweat) glands
9
Q
What are nails made of and where do they begin?
A
- made of hard keratin
- start in stratum basale
10
Q
What are the roles of the epidermis?
A
- avascular
- provides physical and chemical barrier
- regulates fluid
- assists with thermoregulation
- provides light touch sensation
- assists with waste deposit
- critical to endogenous Vit D production
- contributes to cosmesis/appearance
11
Q
How thick is the dermis and how many layers is it made of?
A
2-4mm thick
- papillary layer (superficial layer)
- reticular layer (deep layer)
12
Q
Is the dermis vascularized or avascular?
A
vascularized (HIGHLY)
13
Q
What cells are located in the dermis?
A
- fibroblasts: for toughness & stretchability (w/ collagen & elastin fibers)
- Macrophages & WBC’s
- Mast cells: secrete mediators for inflammation (i.e. histamine)
- Sensory receptors: temp, vibration, pressure, tough (hair root & follicle)
- sebaceous & sweat glands
14
Q
What are the functions of the dermis?
A
- support and nourish epidermis
- house epidermal appendages
- assist with infection control
- assist with thermoregulation
- provide sensation
15
Q
How do blisters occur?
A
- from friction b/w epidermis and dermis which causes a collection of fluid b/w the two layers
16
Q
What is considered in subcutaneous tissue?
A
- adipose tissue
- fascia
- deeper lymphatics
- muscles
- tendon
- bone
17
Q
What tissue is involved with a superficial wound and what are some examples?
A
Epidermis
- abrasion/skinned knee
- superficial 1st degree burn
18
Q
What tissue is involved with a partial-thickness wound and what are some examples?
A
Epidermis & superficial dermis
- blister
- superficial & deep partial-thickness burn (2nd degree
- stage 2 pressure injury
- Wagner grade 1 ulcer
19
Q
What tissue is involved with a full-thickness wound and what are some examples?
A
Epidermis, Dermis, subcutaneous tissue, also could extend to subdermal layers
- Full-thickness burn
- stage 3 pressure injury
- Wagner grade 1 ulcer
- subdermal (4th degree) burn
- Wagner grade 2-5 ulcer
20
Q
What are the 3 stages of wound healing?
A
- inflammatory phase
- proliferation phase
- maturation & remodeling phase
21
Q
How long is the inflammatory phase and what is its purpose?
A
3-6 days could be prolonged
control bleeding & fight germs & bacteria that have entered via the wound
22
Q
What 2 responses occur during the inflammatory phase?
A
- Vascular response
- Cellular Response
23
Q
What is the vascular response during the inflammatory phase?
A
- localized edema
- vessel constriction
- platelet aggregation: to stop bleeding
- chemical mediators: platelets release to promote healing to area
24
Q
What is the cellular response during the inflammatory phase?
A
- platelets
- PNMs: come to wound via chemical signals
- fibroblasts: for vascular growth
- macrophages
- mast cells: produce histamine
- vasoDILation after constriction: about 30 minutes after
- exudate formation: thicker, yellow color
- prostaglandin release (long term vasodilation)
25
What are the cardinal signs and symptoms of inflammation?
- Tumor: swelling
- Rubor: redness
- Calor: heat
- Dolor: pain
- decreased function due to swelling
26
How long and what is the purpose of the proliferation phase?
48hrs - days after *size & health of wound determine this*
- produce tissues required to close the wound
27
What are the 4 critical events during the proliferation phase?
- angiogenesis: formation of new BV's
- Granulation tissue formation: temporary vascularized connective tissue to help allow for contraction and epithelialization
- Wound contraction: pulls together & become smaller (fibroblasts change to myofibroblasts *shape and depth determines this*
- Epithelialization: keratinocytes come across the wound & close it completely
28
How does the shape and depth affect healing time?
- circular wounds contract slowest
- full-thickness contract more than partial-thickness
- MUST be filled from the bottom up
29
What cells are involved in the proliferation phase?
- angioblasts: build new blood vessels
- fibroblasts: build granulation tissue
- myofibroblasts: cause wound contraction
- keratinocytes: re-epithelize the surface of wound
30
How long and what is the purpose of the maturation and remodeling phase?
can continue for several months to 2 years after closure
- Rapid collagen synthesis
- old collagen destroyed
- correct collagen orientation (via induction or tension theory)
31
What is the induction theory for tissue remodeling?
- scar tissue tries to mimic the surrounding tissue
32
What is the tension theory for remodeling tissue?
Davis's Law
- due to forces/stretches the collagen will lay down in correct direction
33
What is the strength of scar tissue?
80% strength of normal healthy tissue
*drops to 64% with repeated healing (second opening)*
- usually happens with venous insufficiency ulcers
34
What are some characteristics of scar tissue?
- insensate
- hairless
- unable to sweat
35
What are the pillars of wound healing?
- moist environment to heal quickly
- don't want scab to form
36
What is primary closure, heal time, and characteristics?
*Primary Intention*
- simplest and quickest
- clean wound, edges approximated (sutures, stables, etc.)
- surgical wounds
- paper cuts, small cutaneous wounds
- 1-14 days to heal
- epithelialization can start within 24 hours
37
What is secondary closure, heal time, and some characteristics?
*Secondary Intention*
- granulation matrix MUST be built
- signs of progression through stages of healing noted w/in acute wounds w/in 14 days - 30 days for chronic
- increased time & scarring
- round wounds that usually need to heal from the inside out
38
How can PT help the healing process of secondary intention wounds?
- heals via phases of healing
- help clean & dress the help wound heal itself
39
What is delayed primary closer, healing time, and some characteristics?
*Tertiary Intention*
- Primary and secondary closure
- dirty wound left open for cleaning
- closed by surgeon
- PT prepares wound for closure
- skin graft, sutures after being left open
- should close within 1-2 weeks of suturing
*wound bed needs to be ready to accept graft with granulation tissue and vascularization*
40
What are chronic wounds?
- a wound, induced by varying causes, whose progression through the phases of healing is prolonged or arrested for any reason
- little or no progress w/in 2-6 weeks
41
What type of cells are present in chronic wounds?
- senescent cells: capable of mitotic activity but barley do so
- higher MMP (matrix metalloproteases) levels: cleans up debris during infla stage but leaves bigger hole to fil
- lower TIMP (tissue inhibitors of MMP) levels: cant control the MMP
- higher inflammatory cytokines
- lack of response to growth factor
- arrest of current of injury: loss of negative charge in wound bed
42
What are some reasons for chronic wound healing?
- absence of inflammation
- chronic inflammation
- hypogranulation/non-advancing wound edge
- Dehiscence
- hypertrophic scarring/keloid
- contractures
43
What is the absence of inflammation and what medical conditions inhibit inflammation?
- the cleaning and soliciting of cells needed for repair does not occur
- increased corticosteroid use for COPD
- HIV or AIDs
- Malnourished
- elderly
44
What is chronic inflammation and how does it hinder wound healing?
- persistent signs of inflammation
- prevents movement into the proliferation phase
- begins to "clean up" and kill healthy tissues
- chronic macrophages and cytokines are present in the wound
45
Why is hypogranulation/non-advancing wound edge not good for wound healing?
- cant fill the wound
- epiboly formation (rounded edges on a wound that go around and not across)
- non-advancing edges is caused by scar formation around the perimeter, repetitive trauma, wound dehydration, and local hypoxia (decreased O2)
46
What is the treatment for hypogranulation and non-advancing wound edges?
- treat reason for chronic wounds
- decrease trauma (if occuring)
- increase moisture (if dry)
- decrease infection (if infected)
- dress wound appropriately to prevent epiboly
47
What is hypergranulation and how can PT's treat it?
- epithelial cells can't climb hill (edges are too high)
- decrease pressure, hypoxia, silver nitrate
- surgery
48
What is dehiscence?
- separation of wound margins due to insufficient collagen production of tensile strength
- could be from: obesity, underlying edema
49
What is hypertrophic scarring/keloid and how do you treat them?
- overproduction of collagen
- at risk wounds: wounds that cross joints, burns
- treat with surgical excisions called z-plasties (keloid)
- compression dressing, silicone gel pads, scar mobilizations (hypertrophic scarring)
50
What is the difference between a hypertrophic scar and a keloid?
Keloid: overproduction of collagen OUTSIDE the wound margins
Hypertrophic scar: overproduction of collagen INSDIE margins of the wound
51
What are contractures?
- pathologic shortening resulting in deformity
*best treatment is PREVENTION*
52
What are 4 deterrents of wound healing?
- wound characteristics
- local factors
- systemic factors
- inappropriate management
53
What factors about wound characteristics hinder wound healing?
- causative agent of wound: surgery or trauma?
- time since onset of wound: acute or chronic?
- wound dimensions: larger and more round increased time to heal
- location: less vascular, underlying bone prominence; thicker skin increases heal time
- temperature: heals best at 30 degrees C or 86 degrees F
- foreign matter: necrotic tissue = increased healing time
- infection: increases healing time
- wound hydration: moist not wet
54
What happens to the skin with aging?
Epidermis:
- atrophies
- thickening of stratum corneum
- decreased Langerhan cells
- atrophy basal membrane
Dermis:
- decreased vascularization
- damage to collagen and elastin fibers
- decreased sympathetic nervous system input (decreased BF via decreased vasodilation)
55
What is Futcher's (Voigt's) line?
sharp demarcation b/w darkly pigmented and lightly pigmented skin in the UE (usually in bicep region)
56
What is Midline hypopigmentation?
line of hypopigmentation over the sternum
57
What is Nail pigmentation?
diffuse nail pigmentation or linear dark bands on nail
58
What are palmar changes?
creases may be hyperpigmented
59
What are plantar changes?
hyperpigmented macules may vary in color and distribution
60
What is Dermatosis Papulosa Nigra?
brown to black papules usually around the face
