POST MORTEM ARTIFACTS Flashcards
removal of organs (esp eyes, tongue, rectum) of carcass by carrion eating animals (e.g., dogs, coyotes, ravens, vultures, etc).
postmortem scavenging
▪ is the rigidity or stiffening of muscles after death due to contraction of musclefibers as ATPs are depleted or exhausted.
▪ usually within 1-6
Rigor Mortis
gradual cooling of the body after death.
Algor Mortis
gravitational pooling/settling of blood to the dependant regions (“down side”) of the body. In this instance, you will know the position of the individual when it was dead.
Livor Mortis (hypostatic congestion)
▪ occurs in heart and vessels.
▪ rbc’s may separate from plasma (esp in animals with high fibrinogen levels, eg horses) = “chicken fat clot”
Postmortem Clotting
▪ HgB released by rbc breakdown (after death) → staining tissues.
▪ especially lining of heart and blood vessels; also common in tissues of aborted fetuses and frozen tissues.
Hemoglobin Imbition
leakage of bile from gall bladder and major bile ducts which stains adjacent tissues green to yellow.
Bile Imbibition
▪ term used to describe an artifactual black discoloration of tissues (similar in an appearance to melanosis).
▪ due to saprophytic/putrefactive bacterial production of hydrogen sulfide (H2S) + iron → iron sulfide (FeS).
Pseudomelanosis
after death, decomposition of tissues begins by progressive release of endogenous enzymes (autolysis) and more gradually by the action of saprophytic bacteria (especially from gut).
Postmortem autolysis / decomposition
putrefaction (rotting), refers to the enzymatic decomposition of organic material (tissue) with production of foul-smelling compounds (eg H2S, NH3, mercaptans), especially by saprophytic / putrefactive bacteria.
Putrefaction and Postmortem Emphysema (bloating)
2 FORMS OF PIGMENTATION:
- EXOGENOUS PIGMENTATION
- ENDOGENOUS PIGMENTATION
are usually caused by inhalation of compounds in mineral or organic dust and become visible in the respiratory tract and draining lymph nodes.
EXOGENOUS PIGMENTATION
occupational pathological pigmentations of the lung (as a group) are called
pneumoconiosis.
The only exogenous pigmentation of concern in animals is caused by anthracosis, which occurs as a result of inhalations of carbon compounds.
anthracosis
EXOGENOUS PIGMENTS
Comprise the following groups of materials:
a) Metals
b) Fungi
c) Colored substances
d) Coarse Materials
may be divided into groups of those related to melanin or those derived from lipids, hemoglobin or porphyrins.
ENDOGENOUS PIGMENTATION
is a normal pigment made by melanoblasts and melanocytes and present in cells, which receive it from melanocytes
MELANIN PIGMENTS
is the presence of melanin in abnormal location such as on the pleura, meninges or heart.
melanosis
congenital complete absence of melanin in an individual.
albino
Macrophages that pick up granules of melanin are called
melanophores
ENDOGENOUS PIGMENTS:
- MELANIN PIGMENTS
- LIPID PIGMENTS
is found as yellowish-brown granules in the cytoplasm of affected parechymal cells.
Lipofuscin
is a condition in which the kidney or liver becomes discolored black because of excess accumulation of non-iron staining brown pigment in hepatocytes and renal
tubular epithelium.
hemachromatosis
usually seen in association with jaundice
Bilirubin
is formed from the tetrapyrrole ring structure of hemoglobin when iron and protein have been removed. It is a normal by-product of hemoglobin breakdown but may occur at times in
excess.
bilirubin
occurs when bilirubin is presented in the plasma in excess
and all tissues are stained yellowish-brown.
jaundice
Jaundice is of three types:
a. Prehepatic jaundice
b. Hepatic jaundice
c. Posthepatic jaundice
occurs following acute hemolytic conditions whereby
bilirubin are brought to the liver in larger quantities to be conjugated with glucuronic acid.
prehepatic jaundice
occurs from direct damage to liver cells and there is release of conjugated and unconjugated bilirubin into the blood.
hepatic jaundice
the bilirubin has passed through the liver but is blocked from entry into the intestine.
posthepatic jaundice
abnormal synthesis of hemoglobin lead to porphyrin accumulation
Porphyrins
arises from phylloerythrin, a metabolite of chlorophyll that has photosensitizing properties.
hepatotoxic type
is caused by plants that contain compounds directly
photosensitive by ingestion without hepatic injury.
primary type
