Studied by 2 peopleTags & Description
What is the definition of pathology?
The study of diseases and all the aspects that are involved with that disease
What is the definition of lesions?
Lesions are anything abnormal in the body
What types of lesions are there?
Gross - can see with the naked eye
Microscopic - sometimes called histological, but typically require another tool to visualise the issue
Pathognomic - The lesion is associated with one cause only, or specific to a cause
What are some diagnostic investigations we can conduct to determine the pathology?
Gross lesions
Histological lesions
Cytology
Haematology and clinical biochemistry
Determining aetiology
What is somatic death?
Somatic death is the absence of life in a body
Irreversible cessation of the vital functions of the brain, heart, and lungs
What is the order in which somatic cells die?
Cardiac myocells and neuronal cells first
Epithelial cells next
Finally fibrous tissue (bone) dies last.
Why is it important to understand the changes that happen post-mortem?
Useful to determine the cause of death
Establish what a real lesion is and what is just post-mortem
Can help determine the post-mortem interval (Time since death)
What is the first post-mortem change that occurs?
Algor mortis - the changing of the internal body temperature to fit the ambient temperature
What factors affect algor mortis?
Initial temperature
Insulation
Ambient conditions
What is the second post-mortem change?
Rigor Mortis - Muscle fibre contractions due to loss of ATP production
This locks the actin to the myosin as ATP is required to release this binding within the muscle.
How long does rigor mortis take to set in? How long does it last for?
1-9 hours for ATP production to stop. Rigor will last for anywhere up to 36 hours after death, at which point the actin and myosin will decay which releases the muscle
What is the third step in post-mortem changes?
Blood changes
What type of blood changes occur post-mortem?
Hypostatic congestion (Livor mortis) where blood will pool in one area of the body. This is typically the side of gravity
Post-mortem blood clotting. This is different to ante-mortem clots as they are typically smooth and in the shape of the vessel they are found within.
What step is post-mortem degeneration and what is it?
Step 4
Post-Mortem degeneration is decay and decomposition
What types of post-mortem degeneration occur?
Autolysis (self decomposition with enzymes)
Putrefaction (Bacteria proliferation)
What factors influence the rate of decay?
Temperature and presence of bacteria
What is the 4th step of post-mortem change? What types are there?
Colour changes.
Haemoglobin imbibition
Bile imbibition
Pseudo-melanosis (False melanin staining)
Pseudo-Necrosis (False nocrosis)
What is the 5th post-mortem change?
Gas production - bloating from the proliferation of anaerobic bacteria (Remember the exploding whale)
What are the final three (6, 7, 8) post-mortem changes?
Organ displacements
Mucosal sloughing in rumen
Lens opacity
Why is it important to understand post-mortem changes?
Some post-mortem changes look like real lesions
Sometimes post-mortem changes will obliterate the real lesions
Note
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