Week 2: Wound Healing (Ch 2) Flashcards
What are the 3 phases of healing?
- Inflammation
- Proliferation
- Maturation and Remodeling
What are the cardinal signs of inflammation?
Swelling (Tumor) Redness (Rubor) Warmth (Calor) Pain (Dolor) Decreased Function (Functio Laesa)
What happens in the first vascular response?
- transudate produces localized edema
- blood vessels constrict to reduce blood loss
- platelet aggregation
- activated platelets release chemical mediators
Which chemical mediators do activated platelets release and what do they do?
Cytokines: signal proteins
Growth Factors: cell growth and differentiation
Chemotactic Agents: attract cells for wound repair
What happens in the second vascular response?
Vasodilation within 30 minutes of injury, exudate formation, histimine release, and prostaglandin release
What does histamine release do?
increased vessel wall permeability, short term vasodilation
What does prostaglandin release do?
long term vasodilation
What cells are involved in the cellular response of inflammation?
platelets, PMNs, fibroblasts, macrophages, mast cells
What are the main stages of Inflammation?
Vascular responses 1 and 2
Cellular response
What are the first white blood cells to reach the site of injury? What do they do?
Polymorphic Neutrophils
Diapedesis, Margination, and Chemotaxis
Which cells are very specific in their activity?
OMNs
What do macrophages do?
enhance inflammatory processes, clean up
What do mast cells do?
enhance inflammatory processes
What are the main stages of the Proliferation phase?
Angiogenesis
Granulation Tissue formation
Wound contraction
Epithelialization
Which phase of proliferation do angioblasts act in? What do they do?
Angiogenesis
forms new blood vessels
Which phase of proliferation do fibroblasts act in? What do fibroblasts do?
Granulation tissue formation
Builds granulation tissue
Which phase of proliferation do myofibroblasts act in?
Wound contraction
Which phase of Proliferation do keratinocytes act in?
Epithelialization
Which cells act in granulation tissue formation?
Matrix metalloproteases (MMPs), integrins
What happens during the maturation and remodeling phase of healing?
- New collagen synthesis
- Old collagen broken down by collagenases
- Reorientation of collagen fibers
How long might maturation and remodeling continue?
up to 2 years after wound closure
What is it called when the edges of the wound can be physically approximated?
Primary closure
What is it called when granulation tissue must be produced to full the wound defect before epithelialization and wound closure can occur?
Secondary closure
How long should it take a wound to close by primary closure?
1-14 days
How long does it take a wound to heal by secondary closure?
acute = within 2 weeks chronic = within 30 days
What happens in delayed primary closure (tertiary)?
wound is cleaned and observed for signs of infections… typically kept open with a wound vac for some reason… then closed with sutures and should heal within 1-2 weeks of suturing
What can cause chronic wounds?
- senescent cells
- higher levels of MMPs
- lower levels of TIMPs
- greater numbers of inflammatory cytokines and chronic wound cells
- arrested curent of injury
What can cause chronic inflammation?
- presence of foreign body in wound bed
- repetitive mechanical trauma
- cytotoxic agents
What else is abnormal when it comes to wound healing?
absence of inflammation, hypertrophic scarring, keloids, contractures, dehiscence
What can cause hypogranulation or nonadvancing wound edge?
hypogranular wound, epibole
