Stages of Healing Flashcards
Define inflammation
- protective response to injury
- removes stimulus, cellular debris, & initiates healing process
What are the cardinal signs of inflammation
- erythema
- edema
- heat
- pain
- loss of function
What does edema fluid balance do
- maintains and regulates the movement of nutrition, oxygen, blood cells, and waste materials across the capillary walls
What happens in the proliferation/migration phase
- granulation tissue continues to mature and strengthen
- hematoma disappears along with signs of inflammation
- the outer edges of the wound come closer together as the injured tissue contracts
What happens during the repair phase
- new blood cells are formed
- the wound site shrinks
- collagen is laid down
Describe the different types of collagen
Type I: main component of mature scars and found in strong tissues such as tendons & bones
Type II: assembled into thin supporting filaments and found in cartilaginous tissue
Type III: thin filaments that make tissues supply and elastic and are prevalent in newborns & early scar and later remodeled into Type I
Type IV: form basement membrane to which epithelial, endothelial, & mesenchymal cells are anchored
How does the tissue response to trauma on the cellular level
- chemical changes
- metabolic changes
- permeability changes
- vascular changes
Purpose of acute inflammation
- destroy or limit effects of causative agent
- remove debris/necrotic tissue = phagocytosis
- preparation for repair
What is the acute inflammation response
- delivery of plasma proteins & circulating cells
- exudate & effusion
- release of chemical mediators
Define margination
- phagocytes move out of blood stream to periphery
Define adhesion
- stick to endothelial cells
Define envagination
- crawl between endothelial cells into tissue
Define fibrin
- barrier to spread of injury
Define local edema
- effective host defense
- leukocytes recruitment
- bacterial containment
- bacterial killing
- limited damage to host tissues
Define systemic edema
- organ injury
- hypotension
- acute lung injury
- acute kidney injury
- DIC
- death
Define chronic inflammation
- result of prolonged stimulus
- accumulation of inflammatory cells
- destructive
- fibrous tissue proliferation
Define fibronectin
- early protein to promote formation, provide tensile strength & glue to hold extracellular matrix substances & cells together
What are the functions of proteoglycans
- bind to fibronectin & collagen to stabilize
- promotes hydration
- contributes to organization & stability of collagen
- basement electrical charge
What are the functions of elastin
- protein synthesized by fibroblasts
- cross linked to form burials for elasticity
What do endothelial cells, myofibroblasts, & fibroblasts do doing the repair phase
Endothelial cells: form new blood vessels
Myofibroblasts: shrink & contract the wound site
Fibroblasts: produce collagen
What are the functions of collagen
- most important fibrous protein for structural & tensile strength
- glue producer
- the structural stability of the extracellular matrix is primarily a consequence of collagen
Define tissue contracture
- newly formed extracellular matrix draws together
- fibroblasts change to myofibroblasts
- excessive shrinkage results in contractures
Describe tissue regeneration
- epithelial cells cover the area, divide, & migrate into tissue using extracellular matrix supported by proteins
- continual replacement of dead parenchymal cells
Describe tissue repair
- scarring occurs if trauma extends beneath the surface layer
- formation of connective tissue scar requires removal of connective tissue matrix
- structural integrity of the parenchymal tissues depends on the formation of the connective tissue scar
What happens during the remodeling phase
- may be initiated as early as 14 days post injury & may last up to a year or more
- granulation tissue will be completely replaced by a dense network of collagen fiber bundles with little or no vascularization
