Acute/Chronic Healing Flashcards
cascade of acute wound healing
hemostasis
inflammation
proliferation
maturation
what is a characteristic of hemostasis
platelet aggregation and clot formation
- allows for movement of cells in and out of the wound space
fibrinolysis
timeline of inflammatory phase
begin immediately and continues for upto 25 days
what capillary changes occur in the inflammatory phase
dilation and become permeable
role of cytokines in the inflammation phase
draw neutrophils and macrophages to the wound
macrophages attract which types of cells?
cytokines
growth factors
bioactive lipids
proteolytic enzymes
how are cytokines characterized in the healing process
additive
synergistic
inhibitory
what do cytokines regulate
cell proliferation
cell migration
cell matrix synthesis
cell deposition and degradation
inflammatory response
what to cytokines come from
platelets
fibroblasts
monocytes
macrophages
endothelial cells
timeline of proliferative phase
within 3 days of injury and lasts a few weeks
what is the proliferative phase characterized by
granulation tissue formation
what cell types assists in the formation of granulation tissue
fibrin
fibronectin
collagen
proteoglycans
glycosaminoglycans
glycoproteins
when does fibroblast proliferation peak
a week post injury
role of fibroblast in proliferation
synthesize and deposit extracellular proteins
how does fibroblast proliferation occur
growth and angiogenic factors cause granulation to occur
what is a risk in the proliferative phase
dehiscence and evisceration
what is dehiscence
wound separation after being closed
what is evisceration
when organs protrude through a wound
what is epithelization
marginal basal cells detaching from the dermis and migrating across the provisional matrix on each side of a wound.
when do fibroblasts enter the wound
within 3 days
peak levels at 7 days
what do fibroblasts do
proliferation and synthetic activity to produce
extracellular proteins
growth factors
angiogenic factors
what is the result of fibroblasts entering the wound
granulation tissue
new capillaries embedded in loose ECM
what is the resultant ECM composed of as fibroblasts enter the wound
collagen
fibronectin
proteoglycans
glycosaminoglycans
cells of the wound bed
proteins
polysaccharides
what types of proteins are in the ECM
matrix - collagen
adhesive - elastin, laminin, fibronectin
what does elastin allow
elasticity and resilience
what does laminin/fibronectin allow for
structural and metabolic support
mediation of tissue remodeling
what forms the ground substance
proteoglycans
glycosaminoglycans
what cells arise at the beginning of angiogenesis? where at? what is their job?
vascular endothelial cells
edges of the wound from damaged vessels and capillaries
penetrate the matrix and form a vascular bud
vascular buds grow until
they reach another capillary
– connect and form a vascular loop
when does epithelization occur
few hours post injury
what is contact inhibition related to? what does it form?
epithelization
rolled edges on a wound
where may epithelial cells come from to complete epithelization
epidermis basement layer
sweat glands
oil glands
hair follicles
where do epithelial cells come from for shallow wounds
epidermal basement membrane
where do epithelial cells come from for medium depth wounds
glands and hair follicles
- form tiny circles of skin
where do epithelial cells come from for deeper wounds
no epithelial cells available
instead granulation tissue forms and fills the base and the epithelial cells come from epidermal layer
when does epithelization occur in deep wounds
will not until the wound is nearly level with normal undamaged tissue
when does wound contraction occur
5 days after wound occurs
how does wound contraction occur
fibroblasts and myofibroblasts rearrange themselves to share the ECM
what is the myofibroblast theory
myofibroblasts attach to collagen in ECM and bring it across the wound via actin
each time the collagen is brought across the wound, the wound bed shrinks
what is the traction theory
many fibroblasts exert traction forces on ECM fibers without coordinated contraction to shorten occurring
when does the maturation phase occur
week out from injury up until a year or more after
what occurs in the maturation phase
fibronectin ECM fills the wound
collagen is laid and forms bundles that provide stiffness and tensile strength
chronic wound healing definition
one that deviates from expected sequence of repair in terms of time, appearance, and response to appropriate treatment
factors that affect wound healing
comorbidities
medications/antibiotic resistance
circulation
nutrition/hydration
lifestyle
age gender race
what is biofilm
microbial colony incased in a matrix that attaches to a wound surface
what is a danger of biofilm
production of destructive enzymes and toxins that promote a chronic inflammatory state in the wound
what is the pneumonic used for wound bed prep
T - tissue assessment
I - infeCtion assessment
M - moisture imbalance
E - edge assessment
what symptoms/symptom clusters can occur from a wound
pain
cognitive changes
fatigue
depression
anxiety
