Inflammation and tissue healing Flashcards
(36 cards)
What are the stages of inflammation and tissue healing? how long do they last? what happens during it?
- Inflammatory Phase (lasts 6 – 10 days): prepares the wound for healing.
- Proliferation Phase : (Day 3 on), Rebuilds & Strengthens the wound
- Maturation Phase, A.K.A. Remodeling Phase: (Day 9 on), process that modifies tissue from weak- non-functional to strong-functional tissue.
What occurs during the inflammation phase? (4 responses)
- Vascular response
- Hemostatic response
- Cellular response
- Immune response
What is the cellular response in the early and late stage of inflammation?
- Early Inflammation (hours after injury) = neutrophils, basophils, and eosinophils (WBCs); Neutrophils are the first WBCs “seen” at the injured site because most WBCs in the plasma are neutrophils - Neutrophils use their phagocytic function to remove bacteria & debris from the site of injury
- late inflammation (24-48 hrs) = predominance of mononuclear monocytes and lymphocytes which peak 3-4 days post injury - predominate late phase bc they live longer than neutrophils
- monocytes convert to phagocytic macrophages
What is the cellular response in that indicates the stage of healing?
- Re-epithelialization, fibroplasia in connective tissues, development of granulation tissues via capillary budding, wound contraction (proliferative)
- Collagen fibers taken up and reformed in a nonrandom orientation that increases tissue tensile strength – “a random to nonrandom change in the orientation of collagen fibers” (maturation/ remodeling)
Arterial-venous capillary network gap so that larger molecules can enter the tissue and cause swelling. This leads to formation of edema
Micro-vessel permeability
What are the physiological factors that change to cause local edema?
- Increased capillary hydrostatic pressure - increases fluid flow out of the capillary
- Decreased capillary oncotic pressure - Reduces fluid flow into the capillary from the interstitium
- Increased fluid flow out of the capillary forming fluid in the tissue
- Lymphatic obstructions
What systemic conditions can cause edema in response?
- CHF
- Renal disease
- Osmotic changes associated with severe burns
When fluid is driven out of the vascular space or capillaries into the interstitial fluid, this is known as ______.
When fluid is driven into of the vascular space or capillaries from the interstitial space, this is known as ______.
Filtration; Reabsorption
During the vascular response, what happens with leukocytes to that leads to increased permeability of the blood vessels? (leads to edema formation)
- Blood flow initially slowes (caused by NE release for vasoconstriction at injured blood vessels, vasoconstriction dilation around injury) - causes seeding of leukocytes
- Margination - L’s line the vessel wall
- Diapedesis - L’s squeeze between the endothelial cells through the vessel walls
- Emigration - L’s migrate from the blood vessel to the perivascular tissue
- Chemoattractants are released from injured tissue that guides L’s to the injured tissue
- Chemotaxis - L’s move toward source of injury in the interstitial space
- Macrophages (L’s) clean up the injured tissue to prepare for healing)
What are the starling forces that encourage filtration?
- Increased capillary hydrostatic pressure (Pc) -Blood pressure against vessel walls, increases with increased blood flow through capillaries
- Increased interstitial oncotic pressure (∏I) aka interstitial colloid osmotic pressure - The pressure that tends to increase diffusion of fluid from inside the vessels into the tissue by increasing the concentration of protein molecules in the tissue.
What are the starling forces that encourage resorption?
- Increased interstitial hydrostatic pressure (PI) - The pressure of fluid against the outside of the vessel wall; the more fluid the greater the pressure
- Increased capillary oncotic pressure (∏C) aka plasma colloid osmotic pressure - The pressure that tends to increase diffusion of fluid from the tissue into the blood by increasing the concentration of protein molecules in the plasma
What chemical mediators cause vasodilation?
- Histamine
- Substance P
- Calcitonin gene-related peptide
- Prostaglandins
What chemical mediators cause increased vascular permeability?
- Histamine
- Bradykinin
- Prostaglandins – Magnifies effect of histamine.
- Hageman factor - clotting factor enzyme in blood
- When these mediators are released, they cause the endothelial cells to constrict and widen the gap to allow leukocytes to move into tissue. Attracted to charges – when a cell is injured, it causes the outside of it to become more negative; the charge change causes in tact cells to shrink (contract)
What chemical mediators chemotaxis?
Histamine
What chemical mediator causes fever?
prostaglandins
What chemical mediator causes pain?
Bradykinin
How does cryotherapy influence the inflammatory response?
- decreases vasodilation and chemical mediators
- reduces metabolic demand of damaged tissue
- diminishes physiologic functions (blood flow, inflammatory response and muscle activity)
How does e-stim influence the vascular response?
- decreases micro vessel permeability of plasma proteins (albumin) by preventing the contracture of endothelial cells
- curbs edema during treatment
What kind of e-stim influences the vascular response (edema)?
burst modulated monophonic pulsed current
- cathode (overall negative polarity) seems to have better results
controls blood loss when vessels are damaged or ruptured and confines the inflammatory reaction to an area immediately surrounding the injury
hemostatic response of inflammation
Contractures may occur in contractile or non contractile tissue due to immobilization or lack of use. What is believed to be the molecular basis that causes contractures?
- it allows anomalous cross-longs to form between collagen fibers; develops when itissue remain stationary because in the absence of normal stress and motion, fibers remain in contact with each other for prolonged periods and start to adhere at their points of interception; prevents normal alignment of collagen fibers when motion is attempted
- it causes fluid to be lost from fibrous connective tissue
characterized by re-epithelialization, fibroplasia, granulation tissue via capillary budding, wound contraction; Involves both epithelial and connective tissues, and the formation of new
capillaries
Proliferative phase of tissue repair
characterized by increased metabolism of randomly oriented collagen fibers which are replaced with collagen fibers oriented to
one and another in a nonrandom arrangement of increased tensile strength
Maturation (remodeling) phase
Involves the migration of epithelial cells across the fund site (open wound in skin) until the open area is covered; when the cells stop migrating, they undergo mitosis, reforming layers of epithelial cells
re-epithelialization
- proliferative phase of epithelial tissue
