Inflammation and repair 2 Flashcards
Chemical Response
Histamine–who releases it?
What does it do?
What happens when it’s out of control?
Released by Mast cells
Causes vasodilation and increased capillary cell permeability.
Out of Control-One gets too much exodate…seasonal allergies.
Prostaglandins–what does it do?
Other Chemical mediators of inflammation–what are they?
What can control these chemical responses in the healing process.
Prostaglandins increase capillary cell permeability and sensitize pain receptors.
Others…Bradykinin
Serotonin
Leukotrienes (respiratory
Can be controlled with antihistamines and cox inhibitors.
Proliferative
(Fibroblastic/Repair) Phase
What is the purpose of this phase?
What is the main process?
What are the outcomes? 2
Cover and impart strength to the injury site. (Time to build up and replace tissue)
Fibroplasia/Collagen Production
Wound Contraction
Neovascularization.
Proliferative–Epithelialization
What does this do?
How does it do it?
When does it stop?
Re-establishment of epidermis
Uninjured epithelial cells from the margins of the lesion migrate and form a bridge over the lesion.
Once contact is made from one margin to the other, migration stops.
What are the 4 steps of epithelialization from the pictures in the book?
- With injury, basal cells detach from the basement membrane.
- The cells migrate while holding on to their “Parent” cells and pull them into the center to close the wound.
- When the two sides meet, movement ceases.
- Basal cells differentiate and proliferate.
Proliferative Phase–Collagen Production
- What makes collagen?
- What is this type of growth called?
- Where does this process take place?
- What do these cells do to get to the injury site?
- As they accumulate, what do they do ?
- Fibroblasts.
- Fibroplasia
- Fibroplasia takes place in connective tissue.
- Fibroblasts MIGRATE to injury site.
- They begin to ALIGN themselves perpendicular to the capillaries.
(Type of tissue needed to form more tissue. Protein that makes up connective tissue, forms strands of fibers that interconnect to make a platform upon which tissue will be constructed.)
Proliferative–Collagen Production (cont)
Fibroblasts make collagen and what else?
What does it do?
What does too much collagen cause?
What causes too much collagen?
- Hyaluronic Acid. (a kind of gummy soup)
- Stimulates cross links in the collagen fibers, giving strength to the granualtion tissue (Forms a network of stength…PTs put stresses on the wound to hopefully make the scar strong and flexible.)
- Excessive scar formation
- Too much stress on new tissue.
Proliferative Phase–Wound Contraction
- What does it do?
- What cell type does it?
- How does it do it?
what are contractures?
- Pulls the edges of the wound together.
- Accomplished by Myofibroblasts. (Fibroblasts with contractile properties.)
- These cells ATTACH to the margins of the wound and PULL the epithelial layer together (picture frame)
Shortening of tissue, not as flexible as it used to be. Happens a lot in wound not properly attended to.
Proliferative phase–Neovascularization
What is it?
What is the process called that accomplishes it?
How does this process work?
What happens once neovascularization is done?
DEvelopment of new BLOOD SUPPLY.
Angeogenesis.
Vessels form small buds which come in contact with other small buds resulting in a capillary loop (pink to bright red color to wound bed)
Many of the capillaries later retract and disappear giving the scar a whitish appearance.
Maturation Phase (scarring phase)
How long does it last?
What happens to fibroblasts and capillaries?
What happens to the water content of tissue?
What color is the scar?
Goal of this phase?
Persists for over a year (1-2 years)
Decrease (blood supply is lessening because new tissue is being formed).
Decrease
Whiter
Restore function
Maturation PHase
Collagen Turnover…
Collagen is sysnthesized and deposited…
What does collagenase do to collagen?
How is this offset?
What types of scars form if this phase gets out of hand?
Collagenase destroys collagen (lysis)
Synthesis dominates lysis in the formation of a scar.
Keloids and hypertrophic scars may form if synthesis is not kept in check.
What is the difference between keloid and hypertrophic scars?
Keloids extend into surrounding tissues outside of the original wound boundaries.
Hypertrophic scars, although raised, have stayed within the boundaries of the original wound.
Maturation Phase
What are the 4 Medical Mgt techniques of scarring?
Pressure (has a way of dampening amt of scarring that occurs.)
Surgical techniques (How well the surgeon closes the wound to get primary intension)
Tension when appropriate. (A guessing game for the amt of tension to add to the scar. There is an art to it)
Immobilization when appropriate. (Conservative PTs–immobilize to keep scar in a primary position. Sports therapy want to get out of immobilization as soon as possible.)
Chronic Inflammation.
How long does it last?
What causes it? 2
What can be the result?
- Lasts for months-years.
- Persistent injurios agents or immune/autoimmune responses.
- increased fibroblast proliferation (scarring and adhesions)
note (Chronic inflammation is dominted by macrophages. They are defensive agents with chm that kill body tissue and invading agents. Chronic inflammation almost always has tissue destruction.)
What are the 6 factors that impede healing?
- Extent of injury–greater damage–greater inflammatory response
- Edema–increased pressure impedes healing and nutrition.
- Hemorrhage–Produces pressure which impedes healing: blood is an irritant outside vascular system
- Poor Vascular Supply–Reduced phagocytic cells and fibroblasts. Reduced O2 and nutrient delivery; reduced clearance of metabolic by-products (smoking–nicotine restricts blood flow through vasodilation?)
- Separation of tissue-primary v 2nd intention.
- Muscle spasm–causes traction and separates wound edges. Can also cause ischemia. (pain causes spasms and spasms cause pain.)
