PATH: Regeneration, Repair, and Healing Flashcards
What are the three phase of cutaneous wound healing?
1) Inflammation 2) Proliferation 3) Maturation
What is the difference between healing with first intention and healing with second intention?
Healing by first intention occurs on clean cuts or slices and will result in no scar formation, but bigger defects will undergo healing by second intention and can result in a substantial scar and contraction
What is granulation tissue characterized by?
Acute inflammation, Neovascularization, edma due to leaky vessels, fibroblasts, collagen; gorssly-looks pink with tiny granules
What is the major cellular contributor to the formation of granulation tissue?
Macrophages
What, generally, is involved in scar formation?
ECM remodeling, tissue remodeling (into granulation tissue), increased collagen deposition and regression of vasculature (blanching), and formation
What cells moderate wound contraction?
Myofibroblasts
How do myofibroblasts develop?
Occurs do to signalling via PDGF, TGF-B, and FGF-2 (secreted from macrophages), fibrocytes, and epithelial cells
What is connective tissue remodeling?
The balance between ECM synthesis and degradation
True or False: Scar tissue has a greater tensile strength than naive tissue.
False- scar (granulation) tissue will never have the same tensile strength naive tissue does
What systemic factors can lead to decreased wound healing?
Nutrition status, Metabolic status, Circulatory status, and hormones
What local factors lead to decreased wound healing? Which is the most common?
Infection (most common/important), mechanical factors, foreign bodies, and size, location, and type of wound
What are keloids?
Hypertrophic scars that occur due to too much wound healing and formation of thick collagen bands
What is wound dehiscence?
Ulceration
What is contracture?
Tissue repair gone wrong in which pts. develop severe, deforming/disfiguring contractions and can cause immobility or loss of function
What is fibrosis?
Excessive deposition of ollagen in tissue often triggered by chronic inflammation
What proteins stimulate fibrosis?
PDGF, FGF, TGF-B, TNF, IL-1, IL-4, IL-13
What is tissue regeneration?
Proliferation of cells and tissues to replace lost structure with complete restitution of the lost or damaged tissue
What is tissue repair?
A combination of tissue regeneration and scar formation by collagen deposition which may restore some original structures, but can cause structural derangements
If ECM damage has occurred, what type of tissue healing response will happen?
Repair
What is the cell population?
The number of cells in a tissue or organ
What are the three groups of tissue based on proliferative activity?
Labile tissue (continuously dividing), Quiescent tissue (stable), and permanent tissue (non-dividing)
What cells produce epidermal growth factor in wound healing?
Macrophages, keratinocytes, and inflammatory cells
What is the effect of platelet derived growth factor?
Migration and proliferation of fibroblasts, smooth muscle cells, and monocytes to areas of wound healing
What are the tissue distributions of collagen Types 1-4?
1- dermis, bone, and tends (ubiquitous in hard and soft tissues, 2- cartilage, IV disks, vitreous humor, 3- smooth muscle, endometrium, arteries, uterus, liver, spleen, and lung (hollow organs, soft tissue) 4- basement membrane
