Lecture 17: Wound Healing Flashcards
Give a morphologic diagnosis (M Dx) for the situation described below
- The brain of a dog has no gross lesions but the dog has demonstrated central nervous signs for the last 10 days. Microscopically most of the blood vessels of the cerebrum are surrounded with numerous lymphocytes.
Brain: Chronic lymphocytic perivascular encephalitis multifocal
Give a morphologic diagnosis (M Dx) for the situation described below
- A dog has a 4 cm diameter nodular skin lesion that has been open and draining fluid for about 10 days. Microscopically the subcutis has evidence of plant material (likely a plant awn), a few neutrophils around the plant material, large numbers of macrophages surrounding the area, a few multinucleate cells, and narrow zone of fibroblast and new capillaries surrounding the entire process.
Skin: Chronic pyogranulometous dermatitis focal
Give a morphologic diagnosis (M Dx) for the situation described below
- Repeated venipuncture over the last 4 days of the jugular vein of a cow has resulted in the formation of a large thrombus attached to the wall. Microscopically the site of attachment has a zone of neutrophils in addition to platelets and fibrin making up the thrombus.
Vein: Subacute fibrinosuppurative phlebitis focal
This is a bovine
- give a M Dx
- small intestine: Granulomatous enteritis, diffuse, chronic
Note the macrophages in the histological slide = granulomatous
Fibrinous
- Would this be acute or chronic
- tough or delicate
- thick or fine
- acute
- delicate, weak
- fine
think the in inside fibrinous, so it is initial to form (first to form)
fibrous
- Would this be acute or chronic
- tough or delicate
- thick or fine
- chornic
- tough
- tough (requires a knife to cut)
think bro in fibrous, bros are tough, like Greg, James and Jose
1?
2?
- Fibrous adhesions
- Fibrinosuppurative peritonitis
What 2 general things happen during the inflammation stage of a wound
- clot formation
- chemotaxis
what 3 general things happen during the proliferation stage of wound healing
- re-epithelialization
- angeiogenesis and granulation tissue formation
- provisional matrix
what 2 general things happen during the maturation stage of wound healing
- collagen matrix
- wound contraction
generallly what are you seeing in these series of wound healing pictures
the edges of the wound is contracting and coming together
- What is the main goal in reparing a wound?
- what will happen if that optimal goal cannot be achieved
- Reconstitute injured tissue to optimal morphology and function.
- Replace injured tissue with viable tissue.
- So granulation tissue will form
- which will lead to fibrous tissue forming
Parenchymal Repair Depends on what 2 things
- Capacity of residual cells to proliferate
- Stromal preservation, 2 things must be intract
- Basement membrane
- Blood supply
What 3 types of cells does parenchymal repair depend on
What is the most common type of repair
- repair by fibrous connective tissue
- Damaged tissue is replaced by granulation tissue which then matures ti fibrous connective tissue (scar tissue)
What is found in granulation tissue?
- Fibroblasts
- Angioblasts / endothelial cells
- +/- pmns, macrophages
In what arrangement will you find fibroblasts and blood vessels in granulation tissue?
Perpendicular to each other
For healing by primary union (first intension) what are 3 things that are needed
- Clean, incised
- Minimal infection
- Minimal foreign material
after 3 months about what % will a wound healed by first intension have compared to its normal strength
80% of normal strength
During healing by first intention what happens after 24 hours
- Neutrophils go to the site
- clot is formed
- Scab is formed
What happens during the subacute, 3-7 days during healilng by first intention
- basal layer mitotic activity
- granulation tissue is forming
- see macrophages
- fibroblasts
- new capillaries
what are macrophages doing during the subacute phase of healing by first intention?
removing debris
What happens during healing by first intention weeks after the would happened
- fibrous union
- remodling and contraction is happening
- What is needed for healing by secondary union to happen
- What can cause delayed healing in this?
- Wide defect; tissue loss; increased wound tension
- Delayed healing due to
- increased necrotic debris
- foreign material
- infection
- presence of exuberant granulation tissue (proud flesh)
not sure what she wanted with this slide
What is happening during the first step (2-3 days) during wound healing by secondary intention (union)
What is happening during the second step (1-2 weeks) during wound healing by secondary intention (union)
What is happening during the third step (3-6 weeks) during wound healing by secondary intention (union)
What is the final product of wound healing by secondary intention
What are these examples of?
- exuberant granulation tissue
- also called proud flesh in horses
What are 8 factors that affect wound repair
- Blood supply: Lose blood supply, healing wont work
- Infection- can delay wound healing
- Foreign body- can delay wound healing
- Wound stability- need good stability
- Age- older they are, slower they heal
- Hormonal influences- Diabetes: prolonged wound healing
- Nutritional status- need Vitamin C and protein
- Chemotherapeutic agents
What are the 5 steps of angiogenesis
- Breakdown of local extracellular matrix
- Proteases
- Capillary bud formation
- Migration of immature endothelial cells
- Endothelial cell maturation and proliferation
- Formation of tube
- Endothelial cell adhesion, basal lamina formation
- Recruitment of pericytes, smooth muscle cells
What signal is needed for the endothelial cell maturation and proliferation step of angiogenesis
- Vascular endothelial growth factor (VEGF)
- is a signal protein produced by cells that stimulates vasculogenesis and angiogenesis
look at this wound repair possible outcomes chart
also look at this chart
