5.2 Lesions and post-mortem change Flashcards
What are the 3 types of changes that can be identified in the cadaver?
- lesions
- agonal change
- post mortem change
What are 7 post mortem changes?
Algor mortis - cooling
Rigor mortis - rigidity
Post mortem clotting
Liver mortis - hypostatic congestion
Post mortem staining
Autolysis - decomposition
Putrifaction - decomposition
Explain rigor mortis
At death:
ADP -> ATP
Rigor mortis:
- reduced ATP = reduced Ca in the SR -> CA build up in cytosol
- reduced ATP = myosin heads cannot release = rigor
What is post Morten clotting of blood?
Blood separates into upper plasma and lower RBC layers
What is hypostatic congestion?
Liver mortis - discolouring of the skin (human and porcine), gravitational pooling of blood post mortem.
what is post Morten imbibition of haemoglobin?
Haemoglobin pigment diffusues out of erythrocytes via small vessel walls.
What is post mortem imbibition of bile pigment?
Cholebillirubin diffuses readily out of the gallbladder, stains tissues adjacent to gall bladder yellow/green
What is autolysis?
- tissue breakdown due to anoxia and cell death
- no inflammatory response
- process enhanced by higher temperatures and failiure to cool body after death
What is putrefaction?
-Dead tissue is invaded by aerobic saprophytic bacteria.
-Proteins, fats, carbs are attacked by enzymes produced by the bacteria
-Produces foul-smelling substances, hydrogen sulphate, indole/skatole
-Psaudomelanosis turns tissues green/brown/black
Autolysis + putrefaction = ?
Decomposition
-faster at higher temps, in air (compared to water)
-deep burial = storage at 4ºc
What is mummification?
Occurs in dry conditions, dryness inhibits bacterial growth so skin and tissue becomes leathery.
What does freezing cause?
Crystalisation of fluids in organs, cells disrupted by thawing, histological changer distorted (CNS and liver badly affected)
