Postmortem Changes and Non-Lesions Flashcards
Autolysis
-Degradation of cells and tissues by the hydrolytic enzymes normally present in tissues
When does autolysis occur?
After somatic death due to total diffuse hypoxia
Putrefaction
Process by which post mortem bacteria break down tissues
Signs of putrefaction?
Color, texture changes, gas production, odors
Which tissues will utilize the quickest? Name them…
The tissues that have the greatest concentration of proteolytic enzymes.
1. GI tract 2. Pancreas 3. Gall bladder 4. Other soft tissues
Rate of decomposition depends on what? (3)
- Cause of death 2. Environmental and body temp. 3. microbial flora (bacterial fermentation continues = gas and heat)
When does rigor mortis begin and how long can it last?
begins 1-6 hours post death and persists 1-2 days
Why does rigor mortis occur and what can effect the onset of it?
It is due to a depletion of ATP and inability of myosin to detach from actin binding site and if the animal was very active before death (high heat) it can accelerate the onset of rigor mortis
What is Liver Mortis (hypostatic congestion)?
Gravity pulls the blood post death (see in fair skinned animals, the lungs and kidney)
When does post-mortem clotting occur?
Several hours post death both in the heart and vessels
Coagulopathies
delay or cause failure of blood to clot
What is the chicken fat clot appearance due to?
separation of RBCs and clotted serum
What are the characteristics of a premortem clot?
- Attached to vessel walls
- dry and dull
- lamellated
- friable
Characteristics of a postmortem clot?
- Unattached
- Shiny and wet
- Elastic
- Perfect cast of vessel lumen
What is hemoglobin imbibition?
Red staining of tissues which is caused by Hb released from lysed RBCs and penetrates the vessel walls which extends into the adjacent tissues
What is bile imbibition? What tissues are stained?
- Bile in the gallbladder starts to penetrate the wall and stains the adjacent tissues (yellow to green brown)
- Liver, intestines, diaphragm
If ruminal tympany occurs what will you see?
An esophageal “bloat line”
What PM changes will you see with the eye?
Corneal opacity which is due to dehydration of the cornea
Pseudomelanosis
green to black discoloration of tissues post mortem due to decomposition of blood by bacteria which forms hydrogen sulfide with iron
When and where is pseudomelanosis seen?
Soon after death and can be seen in tissues in contact with the gut
kidney, liver, spleen, and the gut wall itself
