tissue healing & repair Flashcards
gurlllll
fibronectin:
protein that provides structural support, scaffolding, has ability to glue substances together, tensile strength
list the components of tissue healing
- fibronectin
- proteoglycans
- elastin
- collagen
proteoglycans
what are they composed from
secreted by?
– composed of carbohydrates and sugars
– provide stability and retain water for tissue for being repaired
– secreted by fibroblasts
elastin
who are they secreted by?
function?
secreted by fibroblasts
function: becomes cross-linked to provide tissues with elasticity
collagen
function
provide structural support and tensile strength
collagen type 1
most common and versatile
*predominant in strong tissue like tissues and bones *TENSILE STRENGTH
collagen type 2
what is their half life?
thin supporting filaments found in cartilage and epiphyseal plates
half life: 3 months
collagen type 3
thin filaments found in fresh scars
–essential in wound healing, common in newborns **elastic
collagen type 4
found in fetus, basement membranes
what tissues have decreased blood supply>
- ligaments and tendons
- cartilage
define GROWTH FACTORS
GFs are produced by?
proteins that regulate cell proliferation, differentiation, and migration
- produced by cells involved in the same tissue repair response
sources of GROWTH FACTORS
platelets, fibroblasts, macrophages, endothelial cells
function of platelet-derived growth factors
speeds up healing process
the signals that turn on proliferation of normal cells and cause tissue healing ARE ALSO RESPONSIBLE for proliferation of…
cancer cells
phases of healing
- hemostasis and degeneration
- inflammation
- proliferation and migration
- remodeling and maturation
hemostasis and degeneration of the
goal: stop the bleeding
coagulation clumps platelets together
PLATELETS SUMMON GROWTH FACTORS + inflammatory cells :)
degenerative phase - hemostasis
formation of a hematoma (necrosis of cells), and the start of inflammatory cell response
- inflammation
goal?
how?
VIPs?
inactivate injurious agent and to breakdown dead cells. replace injured tissue with healthy tissue
how? coordinate reaction of body tissues
key components: blood vessels, chemical mediators, CT, collagen
- proliferation and migration
granular tissue
endothelial cells begin to proliferate and start ANGIOGENESIS, channels of new blood vessels to transport o2 and nutrients to healing tissue
* granular tissue: rich network of developing tissue with connective tissue
what are the steps for remodeling and maturation of tissue healing?
- contraction
- contracture
- tissue regeneration
- formation of scar tissue
- chronic wounds
- tissue contraction
myofibroblasts doooo…..
newly formed extracellular matrix comes together, causing shrinkage
myofribroblasts differentiate like smooth muscles and help shrink healing tissue
- tissue contracture
effects
- what does this do to mobility?
excessive shrinkage + pulling of deeper tissue
- limit mobility and organ function
- arthrofibrosis : scarring and thick fibrotic capsule
- tissue regeneration
what kinds of cells restore OG function?
process of parenchymal cells to restore OG tissue
what are the 3 types of cells for tissue regeneration?
1: permanent - regeneration does not happen :/ [cardiac myocytes, CNS neurons]
2: labile: continuously splits [skin, stem, GI]
3> stable: normally dont split but can undergo mitosis [kidney, hepatocytes]
- tissue repair
scarring occurs when the cut extends under the surface layer
chronic wounds..
- in what stage to they usually stay in?
- probable causes?
- chronic wounds may stay in the inflammatory and proliferative phases
- deficiency in growth factors
- wrong biochemicals are present
tissue repair goal
to attempt to restore tissue to OG function
tissue repair depends on…
- type of cell
- type of damage incurred
- other factors
lung - tissue repair
regeneration can only happen if basement membrane is intact.
- if basement membrane is disrupted, healing must be done by repair [fibrosis and scar]
digestive tract
gut cells slough off every 5 days..take 3 weeks for a complete turnover!!
gut health contribute to immune function + serotonin function!!
peripheral nerves
need to maintain the…
when a nerve is cut it goes through myelin degeneration and axonal fragmentation
–w/in 24 hours, new axonal sprouts from central stumps
–need to maintain the neurotubules!
skeletal composition
80 % - cortical
20 % - cancellous (spongy)
bone loss occurs when
imbalance between destruction and production of bone cells
bone: fracture healing
- inflammatory phase
- reparative phase
3.Remodelin phase
inflammatory phase - bone
occurs as inflmmatory cells arrive @ injured site
reparative phase - bone
formation of soft callus formed @ around 2 weeks. once its immobilzed, hard callus replaces it. through enchondral ossification.
fracture remodeling phase
disorganized bones replaced with lamellar bone. 10-30% replaced in adults due to microfractures
factors that affect bone healing
- type of bone
- fracture site and type
-treatment involved
-treatment complicationst
tendons and ligaments
- composition 78% water, 20% collagen
hemostasis begines immediately
inflammatory during the 72 hours then proliferative 2-3 weeks
