Tissue healing

Question 1

what are the 2 classifications of healing?

Answer 1

primary and secondary intention

Question 2

what is primary intention?

Answer 2

minor wounds and surgical incisions with the use of sutures

bring 2 parts of the injury together and let them heal

Question 3

what is secondary intention?

Answer 3

more severe wounds

requires growth b/w the 2 ends of a wound

Question 4

what are the 4 phases of healing?

Answer 4

1. hematosis and degeneration
2. inflammation
3. proliferation and migration
4. remodeling and maturation

Question 5

what is the hematosis phase of healing?

Answer 5

the process of stopping blood flow through the locally damaged vessels into the injury site via coagulation-bleeding has to stop or healing doesn’t progress

shortest healing phase

vasoconstriction f/b vasodilation

degeneration is the formation of hematoma, necrosis of dead cells, and start of inflammatory cell response

Question 6

what is the shortest healing phase?

Answer 6

hematosis

Question 7

what is the inflammation phase of healing?

Answer 7

function: to inactivate the injurious agent, break down and remove dead cells, and initiate healing

typically 1-3 days and sometimes up to 10 days

goal: to replace damaged tissue with healthy regenerated tissue, a fibrous scar, or both

debris removal 5-6 hours post injury and continues for the next 24-48 hours

Question 8

what are cell aggregation centers?

Answer 8

areas of whitish pus

Question 9

what does yellow pus mean?

Answer 9

infection

Question 10

what are the signs of inflammation?

Answer 10

redness, edema, pain, increased temp, and loss of normal function

Question 11

what causes redness?

Answer 11

histamine and other hormone and chemicals released

Question 12

what causes edema?

Answer 12

leakage of fluid, cells, and chemicals

Question 13

what causes pain?

Answer 13

histamine, prostaglandin, and bradykinin release cause hypersensitive and irritable nerve endings

pressure from edema on nerve endings

Question 14

what causes increased temperature?

Answer 14

increased local cell and chemical activity

Question 15

what is an important role of inflammation?

Answer 15

may function to immobilize injured areas

Question 16

what is the proliferation phase of healing?

Answer 16

the phase that begins with debridement to angiogenesis (production of blood vessels)
-newly formed vessels are leaky giving tissue its edematous appearance

about 5 days following injury to around day 21

fills gaps in tissue

increase in fibroblasts and decrease in PMNs

tissue becomes more dense and protective

increase in extracellular collagen that replaces the ECM

increased proteoglycans

2-4 weeks long

growth factors: andothelial production, angiogenesis, and fibroblasts

Question 17

what is the role of fibroblasts?

Answer 17

largely responsible for angiogenesis at about 3-5 days post injury

Question 18

what is early proliferation?

Answer 18

type 3 collagen about 24-48 hours post injury

type 3 is first laid down in injured tissue (weak and thin) to provide early tensile strength

replaced by type 1 collagen by about day 14 to increase cross link formation

Question 19

what is collagenase?

Answer 19

released during epithelialization to prevent overproduction in collagen (too much scar tissue would prevent mobility and lead to Keloid scar formation)

Question 20

what are external signs of proliferation?

Answer 20

redness and swelling due to increased capillaries and extra water volume

pain due to pressure sensitive nerve endings (pain with palpation) and stretch sensitive nerve endings (pain with stretch)

Question 21

what is the remodeling phase of healing?

Answer 21

scar tissue is reduced and remodeled

collagen transition with type 3 being replaced by type 1

thicker and reorient in response to stress applied

wound sensitivity lessens

more parallel fibers and tendons while ligaments have slight deviations bc they absorb stress in multiple planes

about 12 months or long

myofibroblasts are responsible for wound contraction

immature collagen has hydrogen bonds then progresses to covalent bonds to be stronger

at 14 weeks tissue is unresponsive to remodeling

Question 22

what is a contracture of tissue?

Answer 22

excessive shrinkage of tissue near a joint that limits mobility

Question 23

what is arthrofibrosis?

Answer 23

local or global periarticular scarring (around a joint) from surgery or trauma

thickened fibrotic capsule that inhibits motion

causes: prolonged immobilization, infection, or graft malposition post reconstruction

Question 24

is skeletal muscle fiber able to regenerate?

Answer 24

yes, as long as the basement membrane remains in tact

result from mitotic division of satellite cells to promote healing

Question 25

sprain

Answer 25

ligament

Question 26

strain

Answer 26

tendon or muscle

Question 27

is scar tissue contractile or non contractile?

Answer 27

non contractile so when in a muscle it reduces mobility

Question 28

what happens if there is no basement membrane?

Answer 28

the satellite cells have no place to set up and multiply

muscle tissue heal via connective scar tissue and increases risk of reinjury