11- Postmortem changes
What is autolysis?
self-digestion or degradation of cells a nd tissues by hydrolytic enzymes normally present in tissues
What is somatic death?
- due to total diffuse hypoxia
- cells degenerate as described for hypoxic cell injury
What is putrefaction/ decomposition?
process by which post mortem bacteria break down tissues
- gives color, texture changes, gas production, and odors
What tissues undergo autolysis first?
those with greater proteolytic enzymes:
- GI tract
- gall bladder
What are some organs of rapid autolysis?
liver and kidney
What does morphologic appearance of postmortem changes depend on?
- cause of death
- environmental and body temperature
- microbial flora
What effect does cool temp/ refrigeration have on autolysis?
In ruminants, what continues despite death?
ingesta will continue to undergo bacterial fermentation, producing gas and heat
If rigor mortis has not set in after an hour, what should you be cautious of?
anthrax, do not do necropsy
what is rigor mortis?
contraction of muscles after death
- occurs 1-6 hours after death and lasts for 1-2 days
What can accelerate the onset of rigor mortis?
high heat and high activity before death
what is algor mortis?
cooling of the body post mortem, depends of the Temp of body at time of death
what is livor motis?
- hypostatic congestion
- gravity will pull blood post death
Describe a pre mortem clot?
- attached to vessel walls (arteries
- dry and duller color
describe a post mortem clot?
- unattached to vessel walls
- shiny and wet
- perfect cast of vessel lumina
What is hemoglobin inhibition?
red staining of tissue, especially the heart, arteries and veins
How does hemoglobin imbibition occur?
Hg is released by lysedd red blood cells and penetrates the vessel wall and extends into the adjacent tissues
What is bile imbibition?
bile in the gall bladder starts to penetrate the wall and stains the adjacent tissue to a yellow/green/ brown color
What organs are normally are stained by bile imbibition?
liver and intestines
What is bloating?
results from postmortem bacterial gas formation in the lumen of the GI tract
Who bloats faster? herbivores or carnivores
After death, why does clouding of the lens occur?
due to cold temps of the carcass
What is pseudomelanosis?
refers to greenish-black doscoloration of tissues post mortem
- decompostion of blood by bacterial action forming hydrogen sulfide with iron
Where does pseudomelanosis normally occur?
- soon after death
- seen in tissues in close contact with the gut wall