Block 1 Flashcards
Areas to avoid for necropsy (4)
● Areas accessible to animals/people
● Areas that may contain food
● High traffic areas
● Areas difficult to disinfect
Good area for necropsy (3)
● Concrete
● Dirt area in the sun (natural
disinfectant)
● Tarped area
Disposal options post necropsy (5)
b. Disposal options
i. Burial (must be deep enough!)
ii. Rendering
iii. Transport to a disposal site
iv. Incineration
v. Composting
All specimens should be handled and treated as if they are zoonotic. What are Routes of exposure to pathogens during a PM? (4)
i. Oral → wear masks
ii. Splash into eye → use eye protection
iii. Aerosolization
iv. Percutaneous (sharps injury)
External examination look at what?
Exam the skin, wounds, ectoparasites, feet (pads, claws, hooves). Exam eyes, ears, nose, and oral cavity (hemorrhage, blisters, exudate)
Carcass position:
Cows lie on what side? Why?
Horses?
Others?
Cows (ruminants)left because of rumen
Horses (equine) right because of cecum
Others doesn’t matter
Body cavity order (ATC) define
Abdomen
Thorax (confirm for negative pressure in the chest)
a. Remove the Pluck = heart, lungs, trachea, esophagus &
tongue
i. Reflect the tongue and larynx ventrally (to the side)
Cranium
Collection of microbiological samples should be done?
First!
Collected aseptically
Intestines are sampled last
Remove and dissect organs
Solids organs slide like what?
Incise organs with a what?
Open all chambers and valves of the heart by what ratio?
Brain?
Ingesta?
i. Solid organs → “Breadloaf” slice
ii. Organs with capsules need to be incised (ex: kidneys)
iii. Heart → open all chambers and valves
1. Should be 3:1 ratio between left and right ventricle
iv. Brain → always should be removed
1. 2 cuts on either side of foramen magnum & extend
2. 1 cut across the orbit
v. Ingesta → check for foreign material, toxic plants, feed quality, etc.
Formalin collection ratio should be?
10:1 ratio of formalin : tissue
a. Formalin will not penetrate more than 1⁄2 cm of tissue
b. Samples should be no more than 1cm thick
c. Animals <100g may be opened and fixed whole
Toxicology samples should be stored in what?
- Urine, stomach contents, fat, brain, kidney, liver
- Store in aluminum foil inside leak proof bags
Parasitology: external parasites should be preserved in what?
Ethanol
Cavitary effusions, culture store in what?
- Red top/Sterile tube → culture
- EDTA → fluid analysis and cytology
Explain how to properly finish a PM
Explain how to properly finish a PM.
a. Clean and disinfect work surfaces
b. Decontaminate self
c. Record necropsy findings
d. Package the samples
i. Do NOT freeze formalin
ii. Add padding and avoid glass if possible
e. Shipping the samples
i. Ship in leak-proof, crush-proof, well-labeled containers
Define autolysis
- Self-digestion or degradation of cells and tissues by host enzymes
- Occurs after somatic death due to hypoxia
- Tissues affected: Tissues with greater concentration of proteolytic
enzymes catalyze the quickest
— Pancreas first!, then GI, gallbladder, intestines, kidneys,
endocrine
Define Putrefaction
Process when post mortem bacteria breaks down tissues
2. Gives color, texture changes, gas production, odors
Rate of decomposition depends on what (3)
i. Cause of death
ii. Environmental and body temperature (Refrigerate prolong PM)
iii. Microbial flora
c. Examples
i. Rumen mucosa sloughing
ii. Pulpy kidneys
1. Accelerated renal autolysis associated with Clostridium perfringens type D septicemia (happens post mortem)
What is Rigor mortis?
- Contraction of the muscles after death
- Begins 1-6hrs post death, persists for 1-2 days
- High heat and high activity before death increase rigor
- Due to depletion of ATP and inability of myosin to detach from the
actin binding site
What is Algor mortis
- Cooling of the body post mortem
- Depends on the body temperature at the time of death
a. Brain temperature decreases ~18hrs after death
b. Other sites (wool, fat)
What is Livor mortis?
- Gravity pulls the blood post death (blood pooling)
- Variation in color of tissues (skin, lung, kidneys)
What is post-mortem blood clotting?
- Occurs several hours after death in the heart and vessels
- Chicken fat clot → due to seperation of RBCs and clotted serum
a. Proteins that would have been in the serum combine and
form a jelly-like clot & turns yellowish
What is Antemortem clot
Attached to vessel walls
● Dull and dry
● Laminated
● Friable
What is postmortem clot
● Unattached
● Shiny and wet
● Elastic
● Fills the lumen of a vessel
What is hemoglobin imbibition?
- Red staining of tissue (especially the heart, arteries and veins)
- Hb is released by lysed RBCs, penetrates the vessel wall, and
extends into the adjacent tissues