Describe what can be used to determine the time of death of a corpse
there are five different distinct methods whihc can be used to determine time of death:
- Body tempreture:
The body cools after death as there are no heat producing metabolic reactions. The drop in tempreture can be related to time of death; this is algor mortis. The body cools via a sigmoid curve, this can be used and ambient temoreture for up to 24 hours after death to find the estimated time of death
- Extent of muscle contraction:
After death the muscles totally relax and then they stiffen; the stiffening is known as rigor mortis. After death, cells stop recieving oxygen and the muscles use their store of ATP and glycogen to undergo anaerobic reactions, producing lactic acid. After this the enzymes will denature and muscles fibers permenantly contract and shorten. This follows a typical standard pattern which can be used to estimate the time of death.
- Decomposition
The body decomposes in a specific sequence post-mortem. Fist tissues begin breakdwon by autolysis. Then bacteria from the gut rapidly divide inside tissues - this causes decolourisation and gas formation.
- Forensic entomology
This is the study of insect life on a dead body. maggots formed on the corpse are taken and grown to maturity to identify them, the stage in their growth cycle at the time when the corpse was found can then be identified. This indicates the time of death, assuming the eggs were laid soon after death.
- Succession
This is a series of changes that occur in the composition of insects overa time. The community of insects present will change at each stage of succession. This will usually follow a known pattern.
