Wound Healing Flashcards
Embryonic Stem Cells
Pluripotent; isolated from blastocysts
PDGF, FGF, VEGF-A bind GF-R’s on endothelial cells to induce vascular formation by
Endothelial proliferation
Recruitment of pericytes
Deposition of ECM proteins
What occurs during the hemostasis phase of wound healing
Vasospasm → relaxation
Platelets aggregate to expose collagen and a network of fibrin forms
Repair
Replacement of injured tissue
Describe the arrangement of blood vessels in granulation tissue
Arranged perpendicular to fibrosis
Growth factors and cytokines involved in angiogenesis
VEGF, angiopoietin, FGF
Permanent Cell - Non-Dividing Cell
Have left the cell cycle and cannot undergo mitotic division in postnatal life
_________________________
Neurons, Cardiac and Skeletal Muscle
Mechanism of wound healing by primary intention
- Simple Incision
- Sutured incision with acute inflammatory response (2-7 days)
- Redness and swelling
- Zone of acute inflammation; formulation of granulation tissue
- Healing Incison
- Epithelial proliferation and repair
- Maturing fibrous granulation tissue
- Linear fibrous scar (6-12 months)
Mechanism of wound healing by second intention
- Ragged, dirty or infected wound (2-3 days)
- Necrotic slough
- Acute inflammation
- Phase of rapid proliferation of vascular granulation tissue (1-2 weeks)
- Slough and scab
- Epithelial proliferation
- Vascular granulation tissue
- Zone of hyperemia
- Phase of granulation tissue maturation and wound contraction (3-6 weeks)
- Fibrous granulation tissue beginning to contract, pull wound edges closer
- Hyperemia
- Healed wound
- Pale depressed scar with puckering
The proliferation phase of wound healing occurs when? And can last for how long?
3-7 days
3-4 weeks
Quiescent - Stable Cells
Low level of replication; undergo rapid division in response to stimuli. Capable of reconstructing the tissue of orgin
_________________________
Smooth muscle, fibrocytes, vascular endothelial cells, chondrocytes, osteocytes
Collagen
Triple helices with lots of cross linkage providing tensile strength
Characteristics of epithelialization
Proliferate at denuded surfaces
Must disassemble connections to basement membrane and neighboring cells
Must express surface receptors that bind ECM
Regulated by contact inhibition
Tissues ability to return to normal depends on
Retention of ECM structural framework
Regenerative capacity of cells
Myofibroblasts
Form within wounds in response to TGF-beta
Increase with time and severity
Proud Flesh
Hypertrophic scar - excessive granulation tissue
T/F- Capillaries in granulation tissue are sturdy.
False
________________
Capillaries are fragile and bleed easily
When does healing begin?
Immediately after a wound develops
Process of degradation during inflammation phase of wound healing
Leukocytes clean up cell debris from the injury
Wound
Injured tissue
Tensile strength is diminished in what type of wound healing?
Secondary intention
Growth factors and cytokines involved in collagenase secretion
PDGF
FGF
TNF
TGF-beta inhibits
Growth factors are required for cellular
Proliferation
Differentiation
Angiogenesis
Formation of new blood vessels from existing ones
T/F: Proliferation phase of wound healing increases with age and disease.
False
_____________________
decreases