Which inflammation is from pus forming bacteria (strep/staph) that may accumulate on mucosa, skin, or in internal organs? How is this inflammation differentiated by location?
Abscess: localized pus within an organ or tissue
Empyema: localization of pus in a body cavity
Which inflammation is that which occurs on body surfaces or the mucosa of hollow organs (stomach/intestine), causing the loss of epithelial lining?
Which inflammation is of prolonged duration, marked by exudate containing lymphocytes, macrophages and plasma cells, and causes lass of parenchymal cells which results in scarring? What are some examples of destruction caused by this type of inflammation?
Chronic PID leads to destruction of fallopian tubes
Pulmonary fibrosis leads to impaired gas exchange causing dyspnea
Which inflammation is a form of ulcerative inflammation combined with fibrino-purulent exudate? What are examples of this form of inflammation?
Corynebacterium diphtheriae (diphtheria)
Clostridium difficile (pseudo-membranous colitis, abx associated, can cause GI perforation)
Which inflammation is a form of chronic inflammation typically NOT preceded by acute PMN-mediated inflammation, but instead has macrophages and fibroblasts wall off the area forming "giant" cells? What are some examples?
2: regeneration of certain injured tissues (ie., skin)
What type of cells are continuously dividing and replacing themselves? What are some examples?
Hair, skin, GI tract, hematopoietic (blood cell forming)
MOST affected by chemotherapy and radiation therapy.
What type of cells undergo few divisions but can be stimulated to divide more when needed? What are some examples?
Proximal renal tubules, liver (can regenerate to some extent).
What type of cells are incapable of division? Where are these cells found and how do they heal?
Healing accomplished by fibrous scarring.
LEAST affected by chemotherapy.
What are the steps of wound healing?
Hemostasis: vasoconstriction (initially then vasodilation), platelet activation, coagulation (fibrin, plts, RBCs form clot).
Inflammation: removal of debris
Proliferation: growing new cells (granulation tissue, epithelialization)
Maturation (and scarring): collagen produced by fibroblasts increases causing scarring and wound contraction, eventually limited by collagenase
What are the most important cells that participate in healing? What is their role?
PMNs: initial role in scavenging injury site
Macrophages: produce cytokines, angioblasts, fibroblasts, myofibroblasts
How does the skin grow during epithelialization?
Up out of hair follicles and in from edges of wound (from basement membrane).
Why can't epithelialization occur with a full thickness skin loss?
No hair follicles, therefore no epithelialization from depth of wound.
Describe the process of epithelialization.
Cells detach from basal layer and migrate in from wound edges.
When cells meet, contact inhibition stimulates cell proliferation (mitogenic response mediated by epidermal growth factor).
Basal cells differentiate into layers of new mature skin cells.
What is needed in order to cover a large full-thickness skin loss? How does it work?
STSG (split-thickness skin graft)
Skin epithelializes in openings of mesh.
Can a large surface area heal by way of epithelialization? What are examples of wounds that can heal by epithelialization?
"skinned knee", partial thickness burn, small incision/laceration, originally large wound contracted enough for epithelialization to occur
What is the technical term for a scab, what does it consist of, and how does it facilitate epithelialization?
Dried out tissue, serum, clot, proteins, inflammatory cells on wound surface.
Hydrolytic enzymes under the eschar gradually separate it from wound surface (facilitates epithelialization).
What healing cells from macrophages are precursors of blood vessels, proliferate like sprouts from small blood vessels, and appear 2-3 days after injury?
What healing cells from macrophages produce most of the extracellular matrix? What provides attachment of these cells to a matrix in the wound milieu? What is the main protein of connective tissue associated with these cells?
Collagen (comprises 25-35% of whole body protein, forms fibrils in interstitial spaces)
What healing cells from machrophages have hybrid properties of both smooth muscle and fibroblasts, contracting within a few days which reduces the size of the defect (wound), holding margins of tissue in close approximation?
What can happen to tubular structures (such as the bowel) if it has a wound that heals by contraction?
They can stricture and become narrow.
What is an undesirable effect of would contraction? How is this alleviated?
Can cause contracture that limits motion.
One way to overcome this is by Z-plasty.
What does epithelialization predominate over during wound healing by primary intention? How is this accomplished? What is the result?
Edges of wound touch without tension.
Minimal contracture or disfigurement results.
Explain wound healing by secondary intention.
Edges of wound do not touch.
Wound heals "by itself" (no sutures, staples, etc).
More time is needed for healing than with primary intention healing.
Shallow wounds heal by epithelialization.
Deeper wounds heal by formation of granulation tissue, wound contraction, then epithelialization.
What kind of tissue is vascular connective tissue in a wound that consists of capillaries and fibroblasts? What is the old term for it? What does it look like?
"Beefy" red appearance when "clean" (w/out invasive infection)
What are types of collagen and what are some examples?
Type I (most common form): bone, skin, tendon, mature scars
Type II: cartilage, vitreous humor, nucleus pulposus (part of spinal disc)
Type III: embryonic tissues, blood vessels, uterus, GI tract, immature scars, and keloids
Type IV: basement membranes
What are factors that favor wound healing?
Size (smaller heals faster)
Smooth edges & surfaces
Little tension on edges
Abundant vascular supply (depends on location)
What are factors that delay or impede repair?
Retention of debris (foreign body)
Metabolic disorder (diabetes, renal)
Corticosteroids (reversed by Vit A)
Dietary deficiency of ascorbic acid (Vit C), protein, Zn, other nutrients
What are some complications of wound healing?
Wound dehiscence: tension on edges cause separation, infection
Incisional hernia: esp after abd wound infection with fascial dehiscence
Hypertrophic scar: thicker than skin
Keloid: scar grows tall and laterally wider than original wound (esp around shoulders, over sternum, and more common with dark skin)
How much tissue damage is a high velocity injury expected to impart as compared to a low velocity injury? Why?