1. Objective: SWBAT use the evidence of livor mortis, rigor mortis, and algor mortis to calculate the approximate time of death
Do Now:

2. Review Game
Purpose: Be able to guess your word(s) by using only minimal clues
Round 1: charades (no talking)
Round 2: one word
Round 3: definition or example

3. Introducing the Mortis Brothers
The Chemistry, Math and Biology of Death

4. Rigor Mortis Skeletal muscles partially contract
Joints stiffen, lock in place
Onset is 10 minutes to several hours
Rapid cooling can delay it
Lasts up to 72 hours

5. Chemistry of Rigor Mortis
Living muscle cells use oxygen to burn glycogen
After death no oxygen—anaerobic glycosis makes lactic and pyruvic acids
pH falls as acidity increases
Acid promotes a reaction between actin and myosin which work together to contract the muscle
Muscle shortens until all ATP and acetylcholine is used up

6. Exit Ticket
In 4-5 full, complete sentences Give a definition of rigor mortis, livor mortis, and algor mortis. How does this relate to calculating the manner, cause, mechanism or time of death. BRING YOUR CALCULATORS FOR THURSDAY!!!

7. Muscle Contraction

8. Ca and ATP Ratchet the Fibers

9. End of Rigor Mortis
The muscles relax when the body starts to decompose and the fibers begin to break down
Intracellular digestive enzymes are released from the lysosomes as the cells begin to disintegrate, destroying the muscle fibers (autolysis)
Meat is more tender after rigor mortis has passed (Aged Beef?)

10. Livor Mortis Heart stops beating which had been mixing blood
Red blood cells are denser so they sink
Maroon to blue color develops at lowest points
Visible 30 minutes-2 hours after death
Tells you if the body was moved.

11. Livor Mortis
Soon after death, blood is still in vessels, so pressure on an area pushes the bood out—
get blanching up to approximately 4 hours after death
As time goes on blood vessels break down as do blood cells and hemoglobin break down pigment moves out into the tissues
No more blanching
Pressure or constrictive clothing prevents blood from pooling locally
Contact pallor

12. Livor Mortis

13. Livor Mortis
After death cells release enzyme (fibrinolysins) that prevents clotting
Blood in body stays liquid after death
Permanently won’t clot minutes after death

14. Algor Mortis Body cools by Rate of cooling of body after death
Radiation
(the higher the body temperature the more heat lost)
Conduction depends on surface contact
faster if in water because enhanced contact
Convection
Wind cools faster
Rate of cooling of body after death
1.5 °F per hour under “normal conditions”
No real conditions are “normal”

15. Algor Mortis Ambient temperature Newton’s Law of Cooling
T is body temperature, t is time
The bigger the temperature difference, the faster the cooling rate
Outdoors, temperature varies a lot—must correct formula by varying Tambient

16. Algor Mortis
If ambient temperature is constant, Newton’s Law of Cooling is easy to solve
Measure temperature at two different times without moving the body to find k

17. Algor Mortis

18. Algor Mortis Clothing Obesity Ratio of surface area to volume
Insulates body from heat loss
Obesity
Fat insulates, temperature falls more slowly
Ratio of surface area to volume
Children, thin people cool faster
In water?
Cooling is faster since water is a better conductor of heat than air

19. Algor Mortis
New issue
Is there a plateau before body temperature starts to fall after death?
May be up to several hours
Anaerobic cellular chemistry continues after death
Cellular chemistry releases energy as heat