Week 4: Tissue Repair Flashcards
two ways tissues can be repaired
regeneration, scar formation
repair in which tissue is returned to its normal state
regeneration
repair in which connective tissue fills in gaps and mends the tissue
scar formation (“fibrosis”)
tissues are divided into three groups
- continuously dividing (labile) tissue
- stable tissue
- permanent tissue
examples of continuously dividing tissues
bone marrow, skin, GI epithelium
continuously dividing tissue:
cells continuously ______
can easily _____ after ____
contain pool of _______
- proliferating
- regenerate, injury
- stem cells
stable tissues:
- cells have ____ to _____
- can _____, though, if injured
- limited ability, proliferate
- regenerate
examples of stable tissues
liver, kidney
permanent tissues:
- cells ____ ______
- can’t ______ (so injury always leads to ___)
- can’t proliferate
- can’t regenerate, scar
examples of permanent tissue
neurons, cardiac muscle
network that surrounds cells
extracellular matrix (ECM)
two forms of ECM
interstitial matrix, basement membrane
ECM functions
sequesters water/minerals, gives cells scaffold to adhere to, stores growth factor
what cells make collagen?
fibroblasts
____ regulates proliferation, movement, and differentiation of the cells living in it
ECM
if you screw up the ECM, you (can/can not) regenerate
can not
regeneration occurs ____ in labile tissues and occurs _____ in stable tissues
all the time, in limited form
what happens when you remove one kidney?
the other undergoes hypertrophy and hyperplasia
what happens when you remove half of a liver?
it will grow back
in labile tissues, if demand increases, supply ____ _____
increases easily
4 components to scarring procces
- new vessel formation
- fibroblast proliferation
- formation of a collagen scar
- remodeling of scar
term for new vessel formation
angiogenesis
scarring within the first 24 hours
- endothelial cells start proliferating
- fibroblasts arrive
scarring process: 24 hours to few days
granulation tissue is formed
scarring process: weeks later
- dense fibrosis (scar)
- scar is remodeled over time
overview process of scarring (simplified version)
- make granulation tissue
- turn it into a chunk of collagen
granulation tissues is made up of 3 things. what are they?
- new blood vessels
- fibroblasts
- loose connective tissue
true/false, granulation tissue is the same thing as a granuloma
false, it is NOT
type of healing in which wounds closes easily
first intention healing
first intention healing
- ___ wounds
- ____ _____ predominates over _____
- healing is ____
- small
- epithelial regeneration, fibrosis
- fast
examples of first intention healing
paper cuts, well-approximated surgical incisions, replaced periodontal flaps
did you study the “healing by first intention “ timeline slide?
I hope you did! It’s probably going to be exam material!
healing that occurs in larger wounds that have gaps between margins
second intention healing
second intention healing
- ___ predominates over _______
- healing is ____
- fibrosis over epithelial regeneration
- slower
examples of second intention healing
infarction, large burns/ulcers, extraction sockets, gingivectomies
second intention healing has…
- more inflammation
- more granulation tissue
- wound contraction
did you study the “healing by second intention “ timeline slide?
I hope you did!!
wound strength 3 months after suture removal; does it get back to normal?
70-80%, NO
there is a ____ ___ in wound strength in the ___ ___ after suture removal
rapid increase, four weeks
extrinsic factors that lead to bad wound healing?
infection, diabetes, steroids; aberrant cell growth
aberrant cell growth leads to…
keloid scars, proud flesh
