Lecture 20: How the Body Recovers from Injury Flashcards
1
Q
what is scavenging
A
- when used white blood cells, parts of DNA and proteins are taken in by macrophages
- happens during resolution
2
Q
what is it called when there is complete resolution of the tissue to its original state
A
restitutio ad integrum
3
Q
what are histiocytes
A
macrophages in tissue
4
Q
where do some monocytes go and what is their role
A
- go to special capillary areas in the liver, bone marrow ans spleen called sinusoids
- act as a filter tissue to remove abnormal molecules / cells, offending stimuli and dead tissue
- produce growth factors for the proliferation of various cells in the healing response
5
Q
what are histiocytes’ mechanisms of action
A
- chemotaxis
- hypertrophy
- pinocytosis
- phagocytosis
- pseudopodia (active movement)
- activated macrophages develop receptors fro abnormal cells or molecules
6
Q
what is repair and when does it happe
A
- happens if resolution and scavenging isn’t enough, so with a severe injury
- happens in permanent tissue, eg brain and heart
- fibroblasts patch the damage with fibrosin collagen and elastic tissue to form a scar
7
Q
what is the basic sequence of scarring
A
1) haemostasis and blood clotting
2) inflammation
3) angiogenesis and proliferation, forming granulation tissue
4) formation of the scar
5) scar remodelling
6) final scar
8
Q
what happens during angiogenesis
A
- degradation of basement membrane of adjacent blood vessels causing “sprouts”
- endothelial precursor cells from bone marrow are recruited
- sprouts from adjacent blood vessels join to form new vessels. new vessels are leaky
- results in granulation tissue which is weak and oedematous
9
Q
what is granulation tissue formed of
A
- new blood vessels
- fibroblasts
- remaining inflammatory cell (mainly neutrophils)
10
Q
what is fibroblast proliferation mediated by
A
TGF-beta
11
Q
what are complications of wound healing
A
- deficient scar formation leading to dehiscence / ulceration
- excessive scar formation, eg keloid scars
- abdominal adhesions, seen in Crohn’s disease and appendicitis
- contractures often seen in burns
