Wound Healing Physiology (Normal) 2 Flashcards
What are the 1st cells to arrive to the wound site?
When do they arrive?
How long do they stay?
What is their function?
They are initially the most prevelant type of what cell in the site?
The neutrophil colony grows quickest in what type of environment?
Neutrophils
Arrive within 24 hours
Stay 6 hours to several days.
Function as phagocytic cells to remove debris and bacteria from the wound.
White cell
Neutrophils proliferate in hypoxic, acidotic, environments.
What happens when a wound is mostly clean?
WHo arrives?
Once they arrive, they turn into something else…what is it?
These new cells release what to increase what?
Neutrophils acceleration ends.
Monocytes become the main WBC in the wound.
Monocytes transform into Macrophages.
Macrophages release cytokines to increase the inflammatory response. (by inviting and inducing fibroblasts.)
Mast cells are what type of specialized cell?
Mast cells release what at the time of injury? What does it do?
Later, the cell will release the same substance at a lower dose. What does the lower dose stimulate?
Specialized secretory cell.
Mast cells release HISTAMINE at the injury to promote VASODILATION and PERMEABILITY of surrounding vessels and cause temporary EDEMA.
Low doses of histamine stimulate COLLAGEN formation and healing.
After the body has set up the blood clot, what do Mast Cells secrete? What does this substance... stimulate? Accelerate? Destroy? Control?
Heparin
Stimulates migration of endothelial cells
Accelerates activity of neutrophils and eosinophils
Causes a destruction of the hematoma (blood clot)
Helps control hemostasis. (restore normalcy)
Macrophages are key players in what 2 phases of healing?
What do they secrete?
Why?
Inflammatory and Proliferative phases. (hang around for all phases)
Secrete growth factors including Angiogenic (forming blood vessels) growth factor
AGF stimulates endothelial cells from damaged blood vessels to grow in order to deliver nourishing blood.
Macrophages also initiate what additional type of tissue formation? What is it?
Macrophages also have 3 additional functions during inflammation…what are they?
Granulation tissue looks like tiny buds. The color starts pink. As angiogenesis takes place, granulation turns red and beefy.
- Phagocytosis of debris andinfection.
- Autolytic debridement (self cleaning)
- Release of nitric oxide, which kills pathogens.
Chemotatic signals from platelets, macrophages, granulocytes, and keratinocytes all stimulate the proliferation of what type of cell?
Their alignment indicates what?
What do these cells turns into?
Fibroblasts!
Alignment determines future structural strength.
During inflammatory phase, fibroblasts will become myofibroblasts to allow for wound closure by contraction.
What is Current of Injury?
What is its average charge?
Describe the relationship between intact tissue and injured tissue with respect to the current of injury.
An electric current that occurs within the body (and skin) and is a necessary component of the healing process.
-23mV
The flow of ionic current between intact and injured tissue creates an electropositive environment
In Current of Injury, what is Galvanotaxis?
What cells are attracted to the positive pole?
Which one switches to the negative pole during inflammation or infection?
The distinct pattern of current flow and polarity switching; cells of repair are attracted to either positive or negative poles.
Macrophages and neutrophils are attracted to the positive pole.
Neutrophils
What is the purpose or benefit of negative polarity?2
Why does the current of injury not exist in chronic wounds?
How do PTs get it back?
directs migration of epidermal cells and suppresses bacterial growth.
Chronic wounds are typically dry. And the current needs moisture to travel through the tissue.
PTs use e-stim to get it back.
What are the 4 things that would disrupt the inflammatory phase?
- Stimulus for repair***
- Inadequate perfusion and ischemia
- Free Radicals
- Oxygen reperfusion Injury
What is the difference in stimulus for repair between normal acute wounds and chronic wounds?
Acute wounds are caused by vascular disruption from outside the body to inside the body. This causes hemotasis and wound healing cascade.
Chronic wounds rely on an internal stimulus for repair which leads to a gradual onset or nonexistent triggering of the healing cascade.
Epithelialization Phase
What are the benchmarks of this phase?
When does epithelialization begin?
What cells are responsible for resurfacing the wound?
Resurfacing the wound and changes in the wound edges are expected benchmarks.
Epithelialization begins immediately after trauma and occurs concurrently with other phases of wound healing
Keratinocytes.
Keratinocytes
Where are they found?
What do they produce?
How do they create the stratum corneum?
Found in the dermis, epidermis, and lining of various organs of the body, and dermal appendages.
Produce Epidermis
They also spit proteins that cross-link to form the stratum corneum.
Keratinocytes
When do they respond to signals from macrophages, neutrophils, and current of injury once an injury has occured?
What do the Keratinocytes release as a signal?
What receives the signal and what begins as a result?
Within hours
Proinflammatory cytokines.
Fibroblasts whom also release multiple growth factors and the wound healing cascade begins.
