Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
3 Cards in this Set
- Front
- Back
UNIT 4/TOPIC 6- ESTIMATING TIME OF DEATH:
1- Body temperature: -All mammals produce heat from metabolic reactions, so scientist know that the core temp. of humans is around 37°C. - From the TOD metabolic reactions slow down and eventually stop, causing body temp. to fall until it equals its surroundings- this is called algor mortis. - Forensic scientist know that human bodies cool at a rate of 15°C to 20°C per hour, so from the temp. of a dead body they can work out the approximate TOD. - Conditions such as air temp. clothing and body weight can effect the cooling rate of a body. |
UNIT 4/TOPIC 6- ESTIMATING TIME OF DEATH:
2-Degree of muscle contraction: -About 4-6 hours after death, the muscles in a dead body start to contract and become stiff - this is rigor mortis. 1- rigor mortis begins when muscle cells are deprived of oxygen. 2- respiration still takes place in the muscle cells but its anaerobic, which causes a build up of lactic acid in the muscle. 3- cell pH decreases due to lactic acid therefore enzymes cannot produce ATP. 4- therefore bonds in the muscle cell become fixed and the body stiffens. -smaller muscles in the head contract first & larger muscles in the lower body contract last- rigor mortis is effected by temp & degree of muscle development. |
|
UNIT 4/ TOPIC 6- ESTIMATING TIME OF DEATH:
3-Forensic entomology: -when someone dies the body is colonised by a variety of different insects- study of this is called forensic entomology. - TOD can be estimated by identifying the type of insect present on the body- flies are usually first & beetles at later stage. - TOD can also be estimated by identifying stage of life cycle the insect is in - Different conditions affect insect life cycle e.g. drugs, humidity, oxygen & temp. |
uiujiopupiup
|
|
fdfhj
|
uyhikuyhoj
|