Cell ID and Terminology

Question 1

What is the definition of agonal? What are some agonal changes?

Answer 1

Cardiovascular failure of an animal immediately before death.

Passive congestion - liver, lungs, spleen. Reduced venous return from heart.

Pulmonary edema - impaired venous return and increased IV pressure. Fluid pushed out through thin-walled vessels (pulmonary capillaries) into interstitium.

Pulmonary alveolar emphysema - labored active breathing + passive exhalation = less air moved and residual air volume remains in alveolar spaces.

Stomach content in esophagus and trachea, which could lead to aspiration.

Question 2

The extent of post mortem changes depends on? What do the changes result from?

Answer 2

• Tissue of origin
• Temperature at death - body temp, and ambient temp.
• Fleece/fur thickness
• Bacterial flora
• Death to necropsy interval
• Autolysis of cells after circulatory failure - proteolysis by lysosomal enzymes
• Bacterial growth - partly due to physiological flora

Question 3

Name some post mortem changes.

Answer 3

• Algor mortis - cooling
• Rigor mortis - rigidity (1-6 hours after death); starts in heart; persists for 1-2 days
• Livor mortis - hypostatic congestion
• Post mortem clotting
• Autolysis
• Putrefaction
• Texture changes - corneal opacity, gas formation in liver/gut, softening of liver/kidney/pancreas, drying of tissue surfaces
• Post mortem bloat/emphysema - rumen microbes can produce lots of gas
• tissue detachment - mucosa of rumen/retiulum/omasum, hairslip (loss of hair)
• color changes - dark red (hypostatic congestion), diffuse reddish stain (hemoglobin imbibition), greenish-yellow (bile staining tissue close to gall bladder), green-black (from bowel organisms)

Question 4

What is hypostatic congestion:

Answer 4

Passive congestion. Blood sinks due to gravity.

Question 5

What is decomposition? What are the factors of decomposition?

Answer 5

Tissue breakdown.

1. Autolysis - tissue breakdown due to lack of oxygen. No inflammatory response.
2. Putrefaction - dead tissue invaded by anaerobic saprophytic bacteria. Digestion of tissue with gas production. Tissue is green, brown, or black. Generalised tissue breakdown.

Question 6

What are some post mortem artifacts?

Answer 6

1. Freezing - crystallisation, cell disruption
2. Imperfect bleeding - pigs mainly. backbleeding into lungs/thorax if trachea is nicked while cutting jugs and carotids/incorrect angle of knife..
3. Blood splashing - multiple pinpoint hemorrhages in lung/muscle/other organs. Electrical stunning
4. Emphysema - terminal gasping. Especially in thin old cows.
5. Splenomegaly - anasthesia/barbiturate euthanasia.