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58 Cards in this Set
- Front
- Back
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how do you differentiate autolysis and necrosis
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autolysis
- lacks host response - is diffuse |
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how is the rate of autolysis affected by tissue type
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Rapid (in areas w/a lot of enzymes)
• gall bladder and near gall bladder • pancreas • intestines intermediate rate • liver • kidney • spleen slow • bones • cartilage • skin adjacent tissue effect: if intestines autolyze quickly, things close to intestines will also autolyze quickly |
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what tissues have fast autolysis rate
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in areas w/a lot of enzymes
• gall bladder and near gall bladder • pancreas • intestines |
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what tissues have intermediate autolysis rate
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kidney
liver spleen |
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what tissues have show autolysis rate
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bone
cartilage skin |
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what factors contribute to autolysis
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Tissue type
Temperature: higher temp, faster autolysis • Climate temperature • Higher body temperatures bacT: why intestines autolyze so quickly • bacteremia insulation: sheep w/heavy wool, fat animals |
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adjacent tissue effect on autolysis
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rapid autolysis
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intermediate autolysis rate
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rapid autolysis rate
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bacteria increases autolysis rate
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bact increases autolysis rate
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common postmortem lesions
gas accumulation |
• Bloat
o post-mortem o Bloat line: vessels feeding esophagus are compressed, all tissues cranial to thoracic inlet are congested, means that blood was still pumping when bloat happened (ante-mortem) o antemortem - subQ isn’t gas filled o rectal prolapse - from gas production pushing it out • emphysema o gas bubble holes in many tissues, SQ, and visceral organs (play-doh) o way to big to be lipids |
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common postmortem lesions
gastric rupture |
occurs postmortem (esp in rabbits and horses)
if antemortem, there will be hemorrhage around it |
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common postmortem lesions
discoloration |
bile imbibition (green or green yellow staining around gall bladder)
- esp in starving animals - easiest to see in fat Hgb imbibition - due to postmortem hemolysis - stains tissue red - due to euth soln - indistinct margins pseudomelanosis - looks like melanin (black) or green - anywhere in abd - due to bacteria acting on RBC - prominent in lymphoid tissue - never see in aborted fetus b/c not bact in intestine |
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what causes algor mortis
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drop in body temp after death
depends on environ temp and insulation |
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common postmortem lesions
liver mortis |
pooling of blood on down side
purple discoloration seen in pigs and humans |
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common postmortem lesions
rigor mortis |
due to depletion of ATP and glycogen (needed for musc relaxation)
transient - starts at 2-4 hrs - ends at 24-48 hrs |
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bloat line
only in antemortem vessels feeding esophagus are compressed, all tissues cranial to thoracic inlet are congested, means that blood was still pumping when bloat happened |
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common postmortem lesions
bloat associated rectal prolapse |
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common postmortem lesions
gas accumulation - emphysema |
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antemortem bloat
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common postmortem lesion
gas accumulation - emphysema |
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common postmortem lesions
gas accumulation - emphysema |
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postmortem gastric rupture
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antemortem gastric rupture
notice hemorrhage |
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bile imbibition
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Hgb imbibition
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Hgb imbibition
due to RBC hemolysis postmortem |
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Pseudomelanosis
H2S (from bacteria) + Fe (from RBC) => FeS (which is green-black) most common in abd |
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Pseudomelanosis
H2S (from bacteria) + Fe (from RBC) => FeS (which is green-black) most common in abd |
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Pseudomelanosis
H2S (from bacteria) + Fe (from RBC) => FeS (which is green-black) most common in abd |
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Pseudomelanosis
H2S (from bacteria) + Fe (from RBC) => FeS (which is green-black) most common in abd |
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Pseudomelanosis
H2S (from bacteria) + Fe (from RBC) => FeS (which is green-black) most common in abd |
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autolyzed bovine liver
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livor mortis
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euthanasia precipitate
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euthanasia precipitate
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euthanasia precipitate
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euthanasia precipitate
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hemoglobin imbibition due to euth
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hemoglobin imbibition due to euth
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how does formalin fixation prevent autolysis
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kills
- stops putrefaction (kills bact) and autolysis (cross-links enzymes) penetrates - depends on size and density of tissue (1 cm for formalin) hardens - cross-links proteins - stabalizes tissue in its original orientation |
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what are ways to fix tissue
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formalin
heat dessication (not good for histopath) |
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how can you prevent autolysis
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fix tissue
- formalin - heat - dessication refrigeration - slows autolysis by slowing bact growth and enzyme rxns freezing - stops autolysis but ruins tissue for histopath |
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what factors affect fixation
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pH
- acidic formalin forms pigment (acid hematin) volume ratio - 10:1 - tissue binds fixative molecules and depletes them from soln - after a tissue is fixed it can be put in a smaller volume for fixing time - bx should be placed in formalin immediately - necropsies should be done asap - allow 24 hrs to fix tissue |
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what other factors affect histopathology (other than fixation/ preventing autolysis)
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friction
- on mucosal surfaces compression electric current prior sectioning of surgical margins - don't cut through surgical margin - do ink the surgical margin |
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compression = bad juju
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compression = angry pathologist
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friction = unhappy mucous membranes
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friction = a pathologic waste of money
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freeze artifact = pathologist chasing after you with a container of parafin to fix you in and then slice you into little pieces and mount them on a slide
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pH of formalin too acidic
acid hematin |
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mmm steak
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a pomeranian with a bad hair day....
j/k. electrocautery artifact |
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a well seared steak
electrocautery artifact |
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bad sectioning
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good sectioning
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