Exam 4 Lecture Notes- Postmortem Chemical Change Flashcards
- 10 types of decomposition:
- Autolysis
- Fermentation
- Saccharolysis
- Proteolysis
- Lipolysis
- Hydrolysis
- Bacterial Decay
- Bacterial Putrefaction
- Hemolysis
- Oxidation
- Rigor Mortis
- Postmortem Caloricity
- Change in pH
- Postmortem Stain
Postmortem Chemical Changes
Separation of compounds into similar substances by the action of microbial and/or autolytic enzymes.
(general term)
Decomposition
Self destruction of cells; decomposition of all tissues by enzymes of their own formation without microbial assistance.
- Enzymes
- Co-enzymes
- Anti-enzymes
- Lysosomes
Autolysis
Chemical catalysts which are employed by the tissue cells for the digestion and metabolism of food substances during life.
Enzymes
Accelerator substances which increase the activity of enzymes.
Co-enzymes
Substances similar to antibodies. They have a marked inhibitory action on certain enzymes and serve to protect the living tissues against their own digestive agents (autolysis).
Anti-enzymes
A membrane bound body within a cell containing a microscopic droplet of acid hydrolase. At death, acid hydrolase is released (kicks in autolysis). This enzyme is able to break down all matter, fats, carbohydrates and protein. They are capable of destroying the cell membranes, ultimately destroying tissue membrane- this occurs shortly after death.
Lysosomes
Organelles within cells that contain the digestive enzyme of a cell. The primary enzyme is acid hydrolase. After death, the pH of tissue changes from slightly alkaline to slightly acid causing the membranes around this organelle to rupture. Self-digestion begins with the release of enzymes.
Role of the Lysosome
- Amino acids
- Sugars
- Fatty Acids
- Glycerol
End Products of Autolysis
Bacterial decomposition of carbohydrates. It occurs simultaneously with putrefaction and constitutes a major embalming problem. It is the reduction of carbohydrates into simpler substances usually carbon dioxide and water.
- Bacteria, yeasts, and autolytic enzymes play a key role in this after death.
Fermentation
- Anoxidative bacterial fermentation anaerobic type.
- Oxidative bacterial fermentation aerobic type.
Types of Fermentation
No oxygen involved.
Aboxidative bacterial fermentation anaerobic type
Oxygen is directly involved.
- This type will always dominate the fermentation process.
Oxidative bacterial fermentation aerobic type
The decomposition of sugars; similar to fermentation, bacteria, yeasts and autolytic enzymes play a key role in the process.
Saccharolysis
The decomposition of proteins.
- Putrefaction
- Decay
Proteolysis
The decomposition of proteins by action of enzymes of anaerobic bacteria. It is the most unequivocal sign of death.
- Distinct, foul odor more likely to occur with this.
Putrefaction
The decomposition of protein caused by the action of enzymes of aerobic bacteria.
- Foul odors are much less likely
Decay
The decomposition of lipids (fats). Will occur concurrently with the other types of decomposition.
Lipolysis
The decomposition of tissue caused by molecules of water, simply, splitting by water.
Hydrolysis
The destructive influence encountered from tissue acidity which beings to form shortly after death, reaching it’s peak during rigor mortis.
One of the earliest postmortem chemical changes
- The source of the acid is carbon dioxide accumulated in the tissues as a result of:
- Cell metabolism
- The absence of blood circulation to carry the waste material away from the tissue.
- Carbon dioxide + water –> Carbonic Acid
The destructive influence encountered from tissue acidity (beginning shortly after death)
As bodily tissue reaches this pH (in which bacteria will thrive), carbonic acid will directly react with protein causing it to breakdown into amino acids.
- Hydrolysis of protein will begin putrefaction
pH of 8
- Color
- Odor
- Purge
- Desquamation (skin slip)
- Accumulation of gas in viscera, cavities, and other body tissues.
Cardinal Signs of Decomposition (list question)
- Yellow green to green
- Pink-red-purple-brown
- Dark Brown
Color
First external sign of decomposition appears as a silver dollar size circle over the right inguinal or iliac region (lower right quadrant of the abdomen).
- The activity of E.coli causing visceral gas with a combination of hydrogen sulfide and hemoglobin results in a spreading green discoloration eventually covering the body.
Yellow Green to Green
Due to hemolysis resulting in extravascular postmortem stain.
Pink-Red-Purple-Brown
Leatherized condition due to postmortem dehydration.
- Example: Freezer Burn
Dark Brown
Putrefaction is characterized by a nauseating odor resulting from simple amines, complex amines, and the end products of putrefaction.
- Much less noticeable in decay
Odor
- Hydrogen Sulfide
- Hydrogen Phosphide
- Ammonia
- Mercaptans
Examples of odor causing gas
This is completely neutralized by ammonia.
Formaldehyde
The postmortem evacuation of any substance from any external orifice of the body. Specifically, the evacuation of the contents of the repiratory and gastrointestinal tracts.
- May occur through the mouth, nose, and/or anus as a result of visceral gas pressure.
Purge
The separation of the epidermis (outer layer) from the demis (inner layer) as a result of putrefactive softening in the rete mucosum.
- There is a watery infiltration from the minute capillaries between them.
- When the loosened epidermis is pressed upon, it slips or tears away from the dermis.
Skin Slip (Desquamation)
- Postmortem Skin Slip
- Antemortem Skin Slip (Agonal desquamation)
Two Kinds of Skin Slip
The jelly-like substance that binds the dermis to the epidermis.
- The decomposition of this causes skin slip (Maceration)
Rete Mucosum
- Visceral Gas
- Tissue Gas
Accumulated gases in viscera, cavities and other body tissues.
The gas formed in the intestinal tract due to the activity of intestinal flora.
- Example: E.coli (a faculatitive anaerobe)
Visceral Gas
Prefers to be an aerobe existing in free oxygen but can survive as an anaerobe in a non-oxygen environment.
Facultative Anaerobe
Prefers to be an anaerobe not in an oxygen environment, but can survive in oxygen as an aerobe.
Facultative Aerobe
Cannot survive in oxygen, oxygen will kill it.
- Example: Clostridium perfringen
Obligate (strict) Anaerobe
Cannot survive without oxygen.
Obligate (strict) Aerobe
Compressed air is introduced to raise the atmospheic pressure to serveral times normal. At the same time, the patient is given pure oxygen through a face mask. The increase in atmospheric pressure forces enouch air into the patient so that the pressure within the patient’s body equals the pressure outside. This all the patient’s tissues become flooded with more than the usual supply of oxygen.
- H.P.O. (High oxygenated pressure)
Hyperbalic Chamber
Exposure to oxygen under conditions of greatly increased pressure usually in a hyperbalic chamber.
H.P.O. (High Oxygenated Pressure)
Discovered Clostridium perfringen (1894-1899) while a researcher at Johns Hopkins University; later he was Dean of the Medical School.
Dr. William Henry Welch
Abdominal edema, fluid build up.
- When touched, this moves, while gas does not.
Ascites
These are both common intestinal flora.
E.coli and Clostridium perfringen
During this war, trench warfare on battlefields that were previously farm pastures rich with animal waste (Clostridium perfringen) combined with exploding shells caused massive exposure resulting in gas gangrene.
World War I
Noted in advanced putrefaction; it is the formation of gas in the intercellular spaces of the body caused by Clostridium perfringen (Clostridium welchii).
- In it’s antemortem stage, this organism causes gas gangrene.
- It is a spore former
- Encapsulated bacillus
- Almost impossible to kill with chemicals.
- It is the embalmer’s greatest enemy, but is rare.
Tissue Gas (Postmortem emphysema)
- Impossible to stop the spread in advanced stages.
- Can be carried from one body to another by contaminated instruments.
- Gas pockets form beneath the surface in the layers of the skin.
- Eventually, this organism will surface, causing the tissue of these bubbles to blister. Eventually, the body will be covered with these bubbles or blisters. There will be the odor of putrefaction.
- Opening these bubbles will expose this anaerobe to free oxygen, which it cannot tolerate, causing it to form a spore.
- It will appear first in the poorly supported tissues.
Characteristics of Tissue Gas
Tissue gas prior to the bubble stage. When the gas filled area is pressed upon, it has a spongey feeling and emits a crackling sensation as the gas is forced through the intercellular spaces. The tissue is crunchy.
Crepitation
- Scrotum
- Neck
- Shoulders
- Eyelids
- Area around the sternum
Tissue Gas appears first in the poorly supported tissues.
Hypodermically injecting into the gas pockets using the following chemicals:
- Gasoline, kerosene
- High Index Cavity Fluid- 50 or greater
- San Veno (liquid)
Some embalmers have had success with tissue gas by doing this.
Do not push oxygen far enough to reach extremities. Subcutaneous emphysema develops and funeral director gets the body too far gone to work with.
Hospital Life Support Systems
A non-pathological (not caused by bacteria) condition that has no relation to putrefaction.
Subcutaneous Emphysema
It looks and feels like tissue gas; the signs are identical except for:
- It won’t bubble or blister
- It has no odor of putrefaction
Description of Subcutaneous Emphysema
The influx of massive amounts of oxygen and/or carbon dioxide into the tissues causing gas formations in the intercellular spaces.
- Punctured lungs as a result of trauma.
- A massive antemortem dosage of oxygen just prior to death (life support).
Causes of Subcutaneous Emphysema
- Remains may turn dark or even black during injection.
- Severe swelling as in tissue gas.
- No danger of early decomposition; no not increase the strength of fluid.
- Air may be pressed out or squeezed from tissue by working gas toward an open incision or by aspiration and reaspiration.
Effects on Embalming- Subcutaneous Emphysema
The putrefactive odor which is present in tissue gas.
The difference between subcutaneous emphysema and postmortem emphysema.
This is the only positive sign of death. It is a chemical change. The factors that regulate rigor mortis are the same factors that regulate decomposition.
General Decomposition
The products of lipolysis, the destructive hydrolysis of fats during putrefaction. They do not combine with HCHO and, as a rule, present no problem, not even odor.
- The breakdown of lipids and proteins result from the action of bacterial enzymes and autolytic enzymes.
Fatty Acids
- Protein
- Amino Acid
- Amines- simple and complex
- End products
Products of Decomposition
Embalmable with good results.
Protein
Embalmable with poor results.
- Swelling
- No firmness; rubbery
- Distortion of features
Amino Acid
Unembalmable
Amines (Simple and Complex)
Body Poisons
- Cadaverine
- Neurine
- Skatole
- Indole
- Putrescine
Complex Amines
- Ammonia compounds
- Hydrogen Sulfide
- Hydrogen Phosphide
- Mercaptans
- Methane
Simple Amines
- Hydrogen
- Nitrogen
- Water
- Ammonia
- Carbon Dioxide
- Phosphoric Acid
- Sulfuric Acid
End Products of Decomposition
- Age
- Sex
- Corpulence
- Cause and manner of death
- Bacterial and parasitic activity
- Pharmaceutical agents
Intrinsic Factors Governing Decomposition
- Air
- Moisture
- Temperature
- Bacterial and parasitic activity
- Pressure due to earth or clothing
- Vermin including maggots, lice, and rats.
Extrinsic Factors Governing Decomposition
