(Q4) Embalming Chemistry Concepts Flashcards
Primary Disinfection
- Disinfection done before the embalming procedure begins
- May consist of cleaning the deceased; cleaning the eyes, mouth, or orifices
Concurrent Disinfection
- Disinfection during the embalming operation
- Disinfection that occurs during injection and cavity embalming
Terminal Disinfection
- Disinfection after the embalming operation to protect the environment
- May consist of cleaning the deceased, cleaning the instruments and the table
The Three Primary Preservative Agents in Embalming Chemicals
- Aldehydes
- Alcohols
- Phenols
Five Common Characteristics of All Embalming Chemicals
- Inactivate the chemical groups of proteins or amino acids
- Inhibit further decomposition
- Inactivate enzymes (both of the tissues and microorganisms)
- Kill microorganisms
- Destroy or mask odors and eliminate their further production
Inactivate the chemical groups of proteins or amino acids
- The nitrogen in proteins are sites of decomposition
- The chemicals react with the nitrogen to change the structure of the protein (coagulation)
- Coagulation decreases the likelihood that the protein will hydrolyze
Inhibit further decomposition
- Chemicals only slow down decomposition
- therefore, embalming as soon as possible is best
Inactivate Enzymes
- Enzymes are important catalysts of hydrolysis
- Inactivating the enzymes will slow down decomposition
- enzymes are similar to proteins, so preservative chemicals will inactivate enzymes similar to tissue proteins
Kills Microorganisms
- The chemical change that proteins undergo during embalming deprives bacteria of their primary source of nutrition
- Preservative chemicals denature the structural proteins of the bacteria themselves
- The same chemical actions that cause fixation of the tissues of the remains will also produce fixation of the bacterial invaders
Destroys/Masks odors and eliminates their further production
- The odors associated with decomposition are principally due to the formation of amines
- The decomposition of structural proteins produces amines such as putrescine, cadaverine, indole, skatole
- Decomposition of sulfur-containing proteins also contributes to odors
- Protein chemicals react with the nitrogen to effectively neutralize the odor
- Preservative chemicals react with the sources of decomposition (putrefactive bacteria and autolytic enzyme) to eliminate the further production of odors
Reactions of Formaldehyde and Water
- HCHO and water produce methylene glycol
- The proteins are fixed due to the donation of a methylene group (methylene bridge)
Formaldehyde in aqueous solution is:
- formalin
- 37% HCHO by weight
- 40% by volume
How are the proteins fixed?
- the donation of a methylene group (-CH2): methyl/methylene bridge
Reactions of Formaldehyde with Methanol
- Methanol prevents the polymerization of formaldehyde
- Helps extend shelf life
Reactions of Formaldehyde with Proteins
- Main chemical action of HCHO in embalming is the coagulation of protein
- This is brought about by the cross-linking of the peptide bonds of adjacent proteins
- The changes in protein only happen in normal amounts of water; excess water could ever the embalming process by hydrolyzing the cross-links
The changes in protein brought about by formaldehyde are
- Viscosity is increased
- Tissues become firmer
- Resistance to digestive enzymes is increased
- Hydrolysis and water solubility are decreased
Reactions of Formaldehyde with Amino Acids
- Formaldehyde will react with amino acids similarly to protein, because amino acids are the building blocks of proteins
Reactions of Formaldehyde with Strong Bases
- Formaldehyde is destroyed in strong bases
What are two of the strong bases produced by decomposition?
Amines and ammonia
What implications will amines and ammonia have for embalming?
Because Amines and ammonia are strong bases formed by decomposition, and formaldehyde is destroyed by strong bases
- These strong bases may call for a higher formaldehyde demand to combat them
What pH is formaldehyde considered?
a weak acid
Reactions of Formaldehyde with Hemoglobin
- Formaldehyde and hemoglobin produce methemoglobin
- Methemoglobin can turn the body black in 2-3 days
- Preventing the over-formation of methemoglobin is another reason for drainage
Preservative Demand/Formaldehyde Demand
- The amount of formaldehyde/preservative necessary to overcome any nitrogen residue and cause the body proteins to become coagulated
- The total amount of formaldehyde with which protein will combine to be completely preserved
- The greater the decomposition, the greater the formaldehyde demand
Walling-Off Action
- When the concentrated solution seals and sear the capillaries in the tissues preventing distribution and diffusion of the fluid
- causes “shell embalming”
- Caused by too concentrated solutions of formaldehyde or too high rate of flow
What is “shell embalming”
When the embalming solution follows the direct connections between the arterioles and venules and only the surface receives embalming solution, giving a false impression to the embalmier
Distribution
- The movement of arterial solution from the point of injection throughout the arterial system to the arteries.
- Solution moves from carotid (or other injection vessels) to the rest of the arteries
Diffusion
- The movement of arterial solution from inside the vascular system (intravascular) through the walls of the capillaries to the tissues (extravascular
- (after it gets to the other arteries) Solution moves into the capillaries where it disperses to the tissues
