Unit 1:forensic taphonomy

Question 1

Forensic Taphonomy
Death is a process, not all tissues die at once
–Heart stops–> cells deprived of O2–> triggers a series of events:
-___________ (due to anoxic environment)
-cessation of cellular metabolism & repair mechanisms
–________ influenced by interactions of remains w external environment
-placement affects degree of interaction w flora, fauna, & microbiota
-__________, _________, ___, __________ & other gases & local chemical environment greatly affect decomp

Answer 1

• increased chemical disorganization
  -rate of decay
  -ambient temp, moisture, pH, partial pressure of O2

Question 2

4 main constraints of decay process~
-_________
-___________
-________
-____________

Answer 2

-temp
-H2O
-pH (acidity & alkalinity)
-partial pressure of O2

Question 3

4 main constraints of decomp:
Temp:
-altitude, latitude, burial depth, bodies of H2O, air movements, & anthropogenic factors (human activity)
-________ MOST important factor affecting duration of each stage of decay
-_________ or temp coefficient “Q10” states that velocity of chemical rxn inc 2x w each 10 degree C inc
-major role in detection of remains by infrared instrumentation, cadaver dogs, invertebrates & vertebrate scavengers
-onset and relaxation of rigor mortis ______ affected by temps

Answer 3

temp

-rule of 10

-directly

Question 4

4 main constraints of decomp:
Water:
-H2O has a __________ effect on temp due to its high specific heat (longer to warm/cool than adjacent lands)
-________ changes in pH in tissues & environment= dilutes [chemical] intra/extracellularly
-source of H+ for biochemical rxn in all cells
-___________________ decomp according to:
-submerged/partial; salt/fresh; moving/still; varying from normal pH
-saltwater have preserving effects on tissues
-Decomp gases (VOCs) are _________= inc humidity, soil moisture aids in detection of carrion
-presence of moisture encourages floral, microbial growth

Answer 4

-stabilizing
-buffers
-accelerates/retards
-H2O soluble

Question 5

4 main constraints of decomp:
Water (contd):
amount of H2O present directly affects activity of __________ (metabolize carbs, lipids, proteins) by altering pH & [enzyme]
-high moisture content promotes ________ formation
-H2O reduces oxidation of fatty acids, & so, lipids available for binding of salts @ low pH

pH (acidity & alkalinity):
-includes changes in intra/extracellular & environmental pH
-_______________….. leading to decreased enzymatic activities & slow metabolic rxn
-stops completely as enzymes denature/coagulate
-1/2 life of intracellular enzymes ~few hrs

Answer 5

-hydrolases
-adipocere
-intracellular pH lowers

Question 6

4 main constraints of decomp:
pH (contd)
-______________ by anaerobic & facultative bacterial in soil further contribute to lower pH (lactic acid, etc)
-lowered soil pH encourages: 1. fungal growth on remains/clothing/adjacent soils; 2. nutrient uptake in rootlets– invades tissues– furthers phys breakdown of remains
-decaying vegetation also adds _________ to soil
-buried corpses/carcasses create an acidic environment early in decay
-however, week or months PM surrounding soil become more alkaline
-useful for detecting buried remains according to location of “more basic” soils (alkaline)

Answer 6

-fermentation
-humic acids

Question 7

4 main constraints of decomp

Partial pressure of O2~
-_________ of tissues slows in low O2 environments like deep burials, submerged, high altitude; thus slower rates of decay
-depletion of O2 initiates decay, w anaerobic environment stimulating bacterial decomposers
-________ process begins @ enzyme failure due to lack to O2

Answer 7

-oxidation
-autolysis

Question 8

Autolysis & cell death
-autolysis occurs 1st in areas of high rates of _____ synthesis; in cells storing hydrolytic enzymes (secretory cells, macrophages)

Answer 8

-ATP

Question 9

2 Stages of cellular death ~
-Stage 1 (early reversible): _____ synthesis reduced to anoxia &/or direct damage to mitochondria
-cellular activities fail w/o ATP & cells swell
-lactic acid (lowers pH)
-mitochondria swells
-Stage 2 (late irreversible) - accelerated changes w/in cells, leads to ______________ or ______________
-denatured proteins in mitochondria and cytoplasm clump
-membranes of organelles become leaky
-observable tissue necrosis

Answer 9

-ATP
-‘liquefactive necrosis’
-‘coagulative necrosis’

Question 10

Order of Tissue decomp:
Tissues w highest rates of _____ synthesis, biosynthesis & _______________ should decay 1st.
1. ________, stomach, accessory organs of digestion, _______, blood & circulation, cardiac muscle
2. ___________ & lungs
3. kidneys & _________
4. ________ & nervous tissue
5. ___________ muscle
6. ___________ tissues & integument

Answer 10

-ATP
-membrane transport
-intestines
-heart
-air passages
-bladder
-brain
-skeletal
-connective

Question 11

Differential decay of hard tissues
Initial factors involving decay of hard tissues~
- decay slows once reduced to ____________: bone, cartilage, mummified tissue
-___________ affected initially by scavengers
-complete decomp in terrestrial environment
-________ can occur (.001%) in extremely low temps, low O2, little/no moisture
-_________ eventually consumes all collagen (protein in matrix of bone), leaving only inorganic salts

Answer 11

-hard tissues
-skeletal remains
-fossilization
-bacteria

Question 12

Decay of hard tissues (cont)
-interactions w soil & water alter the inorganic chemistry of the bones/fragments

Chemical weathering & diagenesis~
-_____________ of bone is a function of changing ratios of calcium phosphate in bone & soil

Answer 12

-demineralization