Exam 1 Flashcards
What are the phases of wound healing?
- Inflammatory phase: 1-10 days
- Proliferative phase: 3-20 days
- Remodeling phase: 9 days - 2 years
Fibroblasts
cells from which connective tissue is derived
Fibrocytes
mature fibroblasts; responsible for regulating the tissue
Myofibroblasts
responsible for contracting and approximating the wound edges
Mast Cells
responsible for releasing histamine which causes dilation
What do platelets release?
serotonin
What are the three fibrous elements of connective tissue?
collagen, elastin, and reticulin
Ground Substance
a clear and viscous substance that surrounds cells and fibers; consistency depends on external factors applied to the wound
What are the individual steps of the inflammatory phase of wound healing?
- vasoconstriction
- vasodilation
- edema
- necrosis
- Blood cells are brought to the wound (macrophages, erythrocytes, leukocytes, platelets, and plasma protein)
- lymphocyte and lymph node activity
What are the individual steps of the proliferative phase of wound healing?
- Fibroplasia
- Granulation/angiogenesis
- Revascularization
- Wound closure
Endothelial cells
responsible for generating new blood vessels
Epithelial cells
responsible for generating new skin tissue
Fibroblasts follow:
macrophages
Myofibroblasts attract:
endothelial cells
What is essential to wound healing?
revascularization of healthy granulation tissue
Primary Intention
surgeon closes wound by bringing edges together; held together by stitches, staples, glue, etc.
Secondary Intention
wound closes by contraction or re-epithelialization
Tertiary Intention (delayed primary)
a wound that is healing by secondary intention but is then closed by a surgeon
Dehiscence
a wound that is closed by primary intention but later opens as a result of infection or maceration
Contraction
typically involves chronic wounds and doesn’t require granulation tissue; peri-wound tissue moves toward the center of the wound as myofibroblasts are activated by chemical mediators and begin to contract to approximate the wound edges
deeper wounds are more likely to close by contraction
Re-epithelialization
can only occur over healthy granulation tissue; begins within hours of wounding, but the wound must be clean, moist, and granulated
What can prevent re-epithelialization?
- presence of eschar
- dry environment
- chemicals/toxicity
- inappropriate cellular messaging
What are the 4 steps of re-epithelialization?
- mobilization
- migration
- proliferation
- differentiation
Contact inhibition
signals the end of migration/proliferation when the edges of the wound contact one another
T/F: Wound closing signifies wound healing?
False
Once healed, a wound is approximately __ of its original strength
80%
What are two potential remodeling errors?
hypertrophic scarring and keloid scarring
Hypertrophic scarring
excess collagen formation, defined to wound borders