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CHAPTER 4CELL PROLIFERATION, TISSUE REGENERATION AND REPAIR
CHAPTER 4CELL PROLIFERATION, TISSUE REGENERATION AND REPAIR
PRE LECTURE QUIZ TRUE/FALSE
1. Stem cells are undifferentiated cells that have the capacity to generate multiple cell types.
2. DNA synthesis takes place during the G0 phase of the cell cycle.
3. The inflammatory phase of wound healing prepares the wound environment for the healing process.
4. The formation of granulation tissue involves the creation of new capillaries.
5. A large surface wound is likely to heal by the process of primary intention.
T
F
T
T
F
FILL-IN-THE-BLANK
1. _____________ tissues contain cells that normally stop dividing when growth ceases.
2. The extracellular _____________ is secreted locally and assembles into a network of spaces surrounding tissue cells during the process of tissue regeneration.
3. When regeneration cannot occur, healing by replacement with a connective tissue occurs, a process that terminates in ______________ formation.
4. The term _____________ factor is generally applied to small hormonelike proteins that increase cell size and cell division.
5. An abnormality in healing by scar tissue repair is the formation of _____________, which are benign tumorlike masses caused by excess production of scar tissue.
growth
keloids
matrix
Scar
Stable
CELL PROLIFERATION AND TISSUE REGENERATION
Parenchymal tissue
Stromal tissue
-The working part
- The binding part
CELL PROLIFERATION VERSUS DIFFERENTIATION
Cell proliferation-process of increasing cell numbers by mitotic division
Cell Differentiation-process whereby a cell becomes more specialized in terms of structure and function
THE CELL CYCLE
4 distinct phases
PROLIFERATIVE CAPACITY OF TISSUES Varies with tissue and cell type3 divisions of body tissues:a. Continuously doublingb. Stablec. Permanent tissues
STEM CELLS
Incompletely differentiated throughout life
3 Properties:a. Self-renewalb. Asymmetric replicationc. Differential potential
(potency)
INFLUENCE OF GROWTH FACTORS
Small hormonelike proteins that increase cell size and cell division
PDGF, FGF, TGF, and EGF
EXTRACELLULAR MATRIX AND CELL-MATRIX INTERACTIONS
ECM is secreted locally and assembles a network of spaces surrounding tissue cells
Components of ECM:a. Fibrous structural proteinsb. Water-hydrated gelsc. Adhesive glycoproteins
COMPONENTS OF THE ECM
HEALING BY CONNECTIVE TISSUE REPAIR
PHASES OF REPAIR Angiogenesis and ingrowth of
granulation tissue Emigration of fibroblasts and deposition
of extracellur matrix Maturation and reorganization of the
fibrous tissue (remodeling)Usually begins within 24 hours of injury;
evidenced by the migration of fibroblasts and the induction of fibroblast and epithelial cell proliferation
ANGIOGENESIS AND INGROWTH OF GRANULATION TISSUE
MATURATION AND REMODELING OF THE FIBROUS TISSUE
CUTANEOUS WOUND HEALING
The transition from granulation to scar tissue shifts in the modification and remodeling of the ECM
HEALING BY PRIMARY AND SECONDARY INTENTION
Primary intention –sutured surgical incision
Secondary intention- larger wounds which have a greater loss of tissue and contamination
PHASES OF HEALING
Inflammatory Phase Proliferative Phase Maturational or Remodeling
KELOIDS
FACTORS THAT AFFECT WOUND HEALING
Nutritional Status
Blood Flow and Oxygen Delivery
Age
NUTRITIONAL STATUS
Local and systemic factors influence wound healing
Vitamin C and A play an essential role in the healing process
Vitamin C is needed for collagen synthesis
Vitamin A functions in stimulating and supporting epitheilial
BLOOD FLOW AND OXYGEN DELIVERY For healing to occur, wounds must have
adequate blood flow to supply the necessary nutriients and to remove waste, local toxins, bacteria and other debris.
WOUND HEALING IN THE ELDERLY
Age-related changes:A decrease in dermal thicknessA decline in collagen contentLoss of elasticity Elderly are more vulnerable to chronic
wounds, such as pressure, diabetic, and ischemic ulcers as compared to younger persons