2.5 Wound Healing Flashcards
Regeneration
Replacement of damaged tissue with native tissue
Labile Tissues
Constantly regenerating tissue that has stem cells that allows for complete regeneration of the tissue.
Where are the stem cells in the small and large intestine?
Mucosal Crypts
Where are the stem cells in the skin?
Basal layer
Where are the stem cells in the bone marrow?
HSCs
What is the marker of HSCs?
CD34
Stable Tissues
Quiescent cells that can reenter the cell cycle and regenerate if necessary
Permanent Tissues
Lack significant regenerative potential
What are examples of permanent tissues?
- Cardiac
- Neural
- Skeletal Muscle
Repair
Replacement of normal damaged tissue with a fibrous scar and it occurs in tissues that lack regenerative potential
When will repair occur in labile or stable tissues?
When damage to the stems cells occurs, these tissues will regenerate with a fibrous scar
What is the initial stage of repair?
Granulation
What are the 3 components of granulation?
- Fibroblasts
- Capillaries
- Myofibroblasts
What is the function of fibroblasts?
Deposition of type III collagen
What is the function of capillaries?
Providing nutrients
What is the function of myofibroblasts?
Contraction of the wound
What will granulation tissue lead to?
Scar formation
What happens to the collagen during scar formation?
Type III collagen is replaced with Type I collagen
What removes Type III collagen?
Collagenase
What is a cofactor for collagenase?
Zinc
Primary Intention
Wound edges are approximated during healing and leads to minimal scar formation
Secondary Intention
Wound edges are not approximated during healing and leads to granulation tissue filling in the wound, leading to future scar formation and contraction of the wound by myofibroblasts.
What is the most common cause of delayed wound healing?
Infection
What are some deficiencies that lead to delayed wound healing?
- Vitamin C deficiency
- Zinc deficiency
- Copper deficiency
Dehiscence
Rupture of the wound. Most commonly seen after abdominal surgery.
Hypertrophic Scar
They are characterized by deposits of excessive amounts of collagen I which gives rise to a raised scar.
Keloid
Excess production of scar tissue that is grossly out of proportion with the tissue and are largely deposits of collagen III
What populations are most susceptible for keloids?
African Americans
