Parks Cell injury repair and wound healing Flashcards
What are the phases of cutaneous wound healing?
injury-> coagulation-> early inflammation (neutrophils)-> late inflammation (macrophages)-> proliferation-> remodeling
Whats the first thing you need to do to a wound and what does this?
clean it up, macrophages
There are 2 ways a tissue can repair itself. The most common way is (blank) . But, tissues like the superficial epidermis and liver can regenerate their cells to heal almost to normal.
scarring
When you get a corneal abrasion, stem cells come and heal it right up, what kind of healing is this?
regeneration
What contains the corneal stem cells?
the limbus
Crypt cells in your colon are (blank)
stem cells
Where do embryonic stem cells come from and what are they?
blastocysts
pluripotent
The faster you treat a patient, the less liquifactive necrosis and the greater possibility of (blank)
regeneration
If you have persistant tissue damage what will happen?
scarring/fibrosis
Liver, superificial skin wounds, pneumonia all undergo what kind of healing?
regeneration
MI and deep excisional wound undergo what kind of healing?
scar formation
Can cardiac myocytes regenerate?
nope, so they heal by scarring
scarring is made up of what?
does it contract
collagen
no (which is why heart failure happens, you cant stretch your heart for pumping)
What are nondividing permanent cells (terminally differentiated cells)?
cant make them go into cell cycle
like neurons, cardiacmyocytes
What are continuously cycling cells (labile cells)?
cells that continously cycle (superficial skin cells, oral cavity, GI tract)
What are stable cells?
cells that divide only when needed like hepatocytse
How do you kick cells into the cell cycle?
growth factors
What does VEGF do?
stimulate proliferation of endothelial cells; increases vascular permeability
What does EGF do?
mitogenic for keratinocytes and fibroblasts; stimulates keratinocyte migration; stimulates formation of granulation tissue
(hits up parenchymal cells)
What does TGF do?
chemotactic for leukocytes and fibroblasts; stimulates ECM protein synthesis; suppresses acute inflammation
( makes fibroblasts, collagen and ECM)
(blank) is one of the main fibrogenic factors and what does it do?
TGF beta
stimulates fibroblasts to produce Type III collagen (this gets replaced w/ type I later)
What can macrophages, platelets, and epidermal squamos cells produce?
TGF
Why are clots important for healing?
because it contains macrophages, platelets, fibrin. and gives you growth factors to heal
How do you coordinate the signals from the growth factors with signals from the ECM?
via integrins, which elicit cross talk
What helps to coordinate proliferation, remodeling and apoptosis?
integrins
How do you want a wound to look?
red with granulation tissue (indicating you have blood vessels) and dry
How do we stimulate angiogenesis?
VEGF-> stimulates residual endothelium to sprout new vessels and recruit pericytes to form new vessels
In angiogenesis from (blank), endothelial cells from these vessels become motile and proliferate to form capillary sprouts. Regardless of the initiating mechanism, vessel maturation (stabilization) involves the recruitment of pericytes and smooth muscles cells to form the periendothelial layer.
preexisting vessels
Where do you get the endothelial precursor cells (EPCs) ?
from bone marrow
(blank) are mobilized from the bone marrow and may migrate to a site of injury or tumor growth. At these sites, (blank) differentiate and form a mature network by linking to existing vessels.
EPCs
EPCs
So what are the 2 ways to get angiogenesis
from preexisting vessels
from mobilization of EPCs from the bone marrow
What is this tissue:
vascular, edematous, weak and red
granulation tissue
You want your wound to get red, so what should you put on them?
hydrogen peroxide
What does your body do to your granulation?
turns it into scar tissue (this is why your scars on your arm goes from red to white)
When you break your bones what happens?
you get a hematoma
get granulation tissue (get some blood vessels)
get remodeled
When you hear ECM what should your mind be thinking?
fibroblasts (cuz they make collagen)
What is re-epithelization?
How do we do this?
re-growth of the epidermis
EGF
What is special about the basilar epidermis?
they have skin stem cells
What is the first intention of healing?
when you approx. the skin edges together so that it heals better
What is second intention of healing?
allow the wound to granulate (open wound)
Wound healing is affected by (blank)
many factors: meds blood supply nutrition size/shape of wound diabetes infection foreign material degree of immobilization
Do steroids help with wound healing or hurt wound healing?
HURT IT!
(blank) is an area of irregular fibrous tissue formed at the site of a scar or injury. Is it painful?
keloid
no, it just is cosmetically annoying
What is the first thing you do with a wound?
immobilize it!
How does your heart heal after a heart attack?
days 1-3: neutrophils are trafficked to the infarcted area
days 3-7 macrophages come and soften area
days7-10: early granulation tissue which peaks around 14 days and begins being replaced by fibrosis/scarring
scarring becomes dense and complete in 2 months or greater
How come within 4 to 7 days of having an MI, the area of the heart is very soft and fragile?
because there are no myocytes and only macrophages. Which can result in rupture and thus cardiac tamponade
What is this:
compression of the heart by an accumulation of fluid in the pericardial sac.
tamponade
What can myocardial softening do to the papillary muscles?
What would this result in?
Breakage of them
probably dysfunction of the attached mitral heart valve which would result in regurgitation of blood which can lead to heart failure because of inefficient pumping of blood
Why does the patient die in cardiac tamponade?
pericardium fills up and squeezes the heart so it cannot pump and then the patient dies of shock
What are the four endogenous sources of cardiomyocytes?
cardiomyocyte replication
niches of cardiac stem or progenitor cells
bone marrow-derived cardiac
stem or progenitor cells
epicardially derived cardiomyocytes
What are the three exogenous sources of cardiomyocytes?
embryonic stem cells
induced pluripotent stem cells
mesenchymal progenitor cells
When you have cardiac failure or something that ruins your myocytes, how do you heal this and why is this a problem?
you heal this via scarring and fibroblasts, which means you have a lot of collagen and reduced contraction
