What are the three BASIC steps in the repair process?
1. Initial injury or trauma
2. Inflammatory response to the insult
3. Wave of Healing
Can you give me a few examples of "non-dividing permanent cells"?
-(i.e. can't divide and replace)
1. Cells within the CNS
2. Cardiac Muscle
What cells are normally at quiet level. If inflammatory process is turned on then the result is -> A rapid increase in cell division?
If you injure ligament, what do the mesenchymal cells turn into?
What are two examples of cells that are in a stable/quiescent state?
1. Vascular Endothelial Cells
-otherwise we would have leaky vessels all the time
2. Mesenchymal Cells
-sit at the perichondrium/periosteum
Which types of cells have a high rate of turnover in their normal state?
Continuously replacing cells
Do you have the ability to accelerate the process of continuously replacing cells even further after an injury?
What are 3 examples of continuously replacing cells?
2. Epithelial layers of the GI tract
3. Blood-forming cells of the bone marrow
What are the three stages (and timelines of these stages) of healing following connective tissue injury?
Inflammatory Stage - 0-3 Days
Proliferative Stage - 3 Days to weeks
Remodeling Stage - weeks to months
What are the two substages of the inflammatory stage?
1. Vascular Response to Injury
2. Increase in vascular permeability
What is the first thing that happens with the vascular response to injury?
Immediate and short-lived vasoconstriction
What is the purpose of immediate and short-lived vasoconstriction?
gives time to develop a local clot - minimizes bleeding into tissue
What happens after the local clot is formed?
vasodilation of the local area (triggered by local chemical mediators)
What is an example of "local vasodilation"?
Knee contusion - local bleeding and swelling that stay in the knee -> increasing blood flow to AREA (not entire body) Capillary bed at knee expanded
To get local vasodilation, you have relaxation of smooth muscles where????
Pre-capillary Sphincter - (The junction of the arterioles and the capillary beds)
-ring of smooth muscle from arterioles to capillary bed
Relaxation of the pre-capillary sphincter leads to how much increase in blood flow in the local capillary bed?
10x increase in blood flow
What is the more appropriate way to say a tissue is red and warm?
There is evidence of..
1. Active Hyperemia
What are two events that occur to allow an increase in vascular permeability within the microcirculation?
1. Endothelial layers contract
2. Gap formation between cells
What is the result of increased vascular permeability?
Increased leakage of fluids and proteins into the interstitium
What does increased leakage of fluids and proteins into the interstitium?
What is edema or swelling caused by TRAUMA?
What happens if the injury is a mild one?
Get this response (increased permeability) at the post-capillary venules
What happens if the injury is a bad one?
Get this response (increased permeability) further up the arteriole side
Where can increased permeability occur if the injury is attributed to direct damage to the endothelium?
anywhere within the microcirculation
Without direct insult but there is a local tissue injury, the overall response is primarily dependent on....?
Severity of Injury
Where does increased permeability happen at...
Mild injury - PCV
Moderate - PCV and capillaries
Severe - PCV, capillaries and arterioles
What would you say in your note if there is evidence of bruising?
What do endothelial cells rest on?
Can a RBC "leak out" of a vessel if the basement membrane remains intact?
What will occur if the basement membrane remains intact?
NO Hemorrhaging of RBCs into tissues (no bruising "ecchymosis")
-can leak fluid and proteins
What will occur if the basement membrane is damaged?
release RBCs into tissues - >Bruising (ecchymosis)
What is the name of each stage listed?
A - Immediate Transient
B - Immediate Prolonged
C - Delayed
D - Sustained
Describe Stage "A"
A - Immediate Transient Response
0:) happens within minutes
1:) Increase in permeability that almost immediately disappears
2:) Only see with a MILD injury - this is short-lived
3:) "Monophasic response" - only one blip and the tissue goes on
What is the classic example of an immediate transient response?
Triple Response of Lewis:
1:) Flush - reddening
2:) Flare - enlarges
3:) Wheal - swelling
Describe the Flush Response of Lewis:
0:) reddening of the skin in the area of insult
1:) primarily due to Increased Blood Flow (vasodilation) to local tissues
2:) immediate vasodilation controlled by local mast cells releasing histamines that respond to vessels
3:) mast cells are found in the tissue close to vessels
----Convenient because they house vasoactive amines in a RTG state
Describe the Flare Response of Lewis:
1:) Reddened area of skin ENLARGES as the vasodilation expands due to the release of local neuropeptides from the surrounding NERVE endings that can cause a BIGGER reaction
Describe the Wheal Response of Lewis:
1:) An area of swelling may emerge which is demonstration of increased vascular permeability allowing fluid accumulation in the tissues
Describe stage "B".
Immediate Prolonged response
0:) more severe response
1:) (hours to days)
2:) "biphasic response"
Describe stage "C".
Delayed prolonged response -
1:) don't see anything for a few hours and then suddenly see changes
2:) classic example = sunburn
-painful to touch, reddened, swell a little
3:) monophasic response
Describe stage "D".
Sustained response severe injury
1:) Immediate and Sustained
2:) examples fractures, and 3rd degree burns
3:) Monophasic response