week 6 Flashcards
- chemical and physical changes
- vascular circulation stops with death
- shortly after non traumatic death, body temp increases
- increase in body temp -> because of pathological condition
- febrile diseases, viral/bacterial infections, some nervous disorder
post mortem caloricity (4)
algor mortis (2)
- physical changes
2. rate of temp change based on intrinsic and extrinsic factors
intrinsic factors of algor mortis (4)
- surface area to body mass ratio
- higher surface area to mass ration = body will cool faster - build
- adipose tissue and muscle tissue retain heat - amount of post mortem caloricity
- pathological conditions
- autoimmune diseases, febrile diseases
extrinsic factors of algor mortis (5)
- environment (temp)
- coverings on the body (clothes, sheets, etc)
- pathological conditions (infections)
- pharmaceuticals
- controlled substances (illegal drugs, alcohol)
rigor mortis (4) characteristics
- chemical change
- happens within few hours of death, last for up to 3 days
- duration is dependent on multiple variables
- helps us determine time between death and embalming
process of sliding filament model (9)
- while muscle is at rest, actin and myosin dont touch
- actin is “blocked off” by tropomyosin and troponin
- our brain send a signal or action potential for our muscle to move causing calcium to be released
- tropomyosin binds with calcium is pulled away from the actin strand
- myosin binds to an AT Molecule which changes the ATP -> ADP
- myosin then binds with actin
- sarcomere, shrinks, muscle contracts
- ADP unbinds, ATP rebinds with myosin to release actin
- muscles relaxes and process can restart
rigor mortis process (4)
- muscle movement is a process that occurs at the cellular level
- involves three key players; actin, myosin and ATP
- rigor remains until proteins are broken down or until the cross link bridges are broken down via the embalmer massaging the tissue
- more muscle tissue = more rigor
livor mortis characteristics (3)
- physical change
- intravascular purple/red discoloration
- can help determine amount of time between death and embalming
post mortem stain characteristics (3)
- chemical change
- heme is released because of hemolysis
- usually present in dependent tissues
post mortem stain sequence (5)
- hypostasis
- livor mortis
- hydrolysis
- hemolysis
5 post mortem stain
pH shift (-> acidic) (2)
- metabolism continues after death
2. production of metabolites with no way to eliminate them creates an acidic environment
pH shift (->) basic (4)
- proteins break down releasing nitrogen into the body
- not uniform throughout the body
- may have “microenvironment” with different pH levels throughout the body
- temperature can also have an affect on pH levels
decomposition characteristics (2)
- chemical change
2. body decomposition as a result of hydrolysis, autolysis, and microbial influence
signs of decomposition (9)
- discoloration
- odor
- desquamation
- anasarca
- swelling
- purge
- vascular breakdown
- adipocere
- skeletonization
entropy characteristics (6)
- life is the act of cheating entropy
- cells of the body are not dead after brain death occurs; muscle and organ cells live for several hours, skin and bone cells stay alive for days
- lactic avid in the muscles is not cleared by circulation and becomes metabolic waste
- protein breakdown causes nitrogenous waste
- atp is no longer synthesized, muscles “lock” then “unlocked” when actin and myosin decompose
- bacterial infestation begins and spreads
embalming purpose (2)
- disinfect bacteria that cause decomposition
- hold together biomolecules that have started to degrade
decomposition order
carbs-> soft proteins-> lipids-> hard proteins-> bone
carbohydrate decompostion process (4)
- begins with hydrolysis of glycogen into glucose monomers
- monomers decompose further into organic acids, alcohols, and other oxygenated compounds like ketones, aldehydes, esters, and ethers
- these compounds are then further broken down into carbon dioxide and water
- contributing factor to the acidic pH shift
carbs and oxygen characteristics together (2)
- in a more aerobic environment, carbs will be broken down by fungi and bacteria and will decompose into sugars into glucuronic acid, citric acid or oxalic acid
- in a more anaerobic environment, sugars become into lactic acid, butyric acid and acetic acid
protein decomp (3)
- occurs via putrefactive, hydrolytic, and other processes
- saprophytic bacteria largely contribute to protein breakdown
- cells also have an auto-destruct mechanism that kicks in after death
- pH basic to acidic
- cell membrane surrounding lysosome within the cell lyses
- lysosome contains digestive enzymes that are released
- enzymes begin digesting surrounding cellular substances
protein decomposition sequence (4)
- proteins do not degrade at a uniform rate
- tissues with a lot of proteolytic enzymes decompose early (pancreas, GI TRACT)
- Harder proteins decompose more slowly (muscle protein, collagen)
- keratin protein is the most resistant to decomposition (hair, skin, nails)
- decomposition of proteins by the enzymatic activity of anaerobic bacteria
- in anaerobic conditions, proteins are decomposed by an enzymatic process
- process is regulated by moisture, temp, and bacteria content
- creates phenolic products, methane gas, ammonia, thiols, pyretic acid, sulfides and hydrogen sulfide gas
- thiol
putrefaction
an organic compound containing the group -SH
thiol (mercaptan)
- a chemical reaction in which a substance is broken down or dissociated by water
- amide bond breaking reaction that involves the addition of water
- enzymes are essential to the process
- products of the reaction polypeptides, amino acids, and other amino acids linked simple polymers
hydrolysis
other protein breakdown processes (2)
- decarboxylation
2. deamination
process that chemically removes the carboxylic acid group from the amino acids and also from the terminal end of proteins
-associated products are cadaverine and putrescine
decarboxylation
enzyme driven process that removes the amino group from amino acids
-associated product is ammonia
deamination
heme decomposition (3)
- in living person, heme is broken down by catabolism into a green molecule known as biliverdin
- biliverdin is then reduced to bilirubin which is secreted as bile from the liver
- when death occurs, unprocessed bilirubin and biliverdin cause post mortem stain by seeping from the capillaries and into the tissues
jaundice discoloration (3)
- blood contain low levels of bilirubin
- bilirubin gets pushed into surrounding tissues when it is over concentrated causing yellow discoloration
- when embalming occurs, yellow is converted to a green color, because bilirubin is converted to biliverdin
nucleic acid decomposition (2)
1 nucleic acids decompose into sugars, nitrogenous bases, and phosphates
2. nitrogen bases are broken down in reactions that release ammonia
lipid decomposition (7)
- adipose tissue makes up a large portion of lipids in the human body
- phospholipids break down into phosphates and fatty acids
- sterols break down into compounds like aldehydes, ketones, and other organic compounds that eventually break down further into carbon dioxide and water
- triglycerides are hydrolyzed by enzymes
- aerobic degradation produces aldehydes and ketons and eventually carbon dioxide and water
- anaerobic degradation directly produces carbon dioxide and water but can also produce adipocere
7 under very alkaline conditions, body fat is saponified and turns into wax0 like soap
bone decomposition (4)
- diagnosis is the term for bone breakdown
- collagen is first eliminated via bacterial action to amino acids
- minerals like calcium are then degraded
- bone eventually turns into dust
