What happens to your body after you die?

Answer 1

Heart stops beating and/or lungs stop breathing. Body cells no longer receive supplies of blood and oxygen. Blood drains from capillaries in the upper surfaces and collects in the blood vessels in the lower surfaces. Upper surfaces of the body become pale and the lower surfaces become dark. Cells cease aerobic respiration, and are unable to generate the energy molecules needed to maintain normal muscle biochemistry. Calcium ions leak into muscle cells preventing muscle relaxation. Muscles stiffen and remain stiff(rigor mortis) until they begin to decompose. Rigor mortis refers to the state of a body after death, in which the muscles become stiff. It commences after around 3 hours, reaching maximum stiffness after 12 hours, and gradually dissipates until approximately 72 hours after death. Rigor mortis occurs due to changes in the physiology of muscles when aerobic respiration ceases. Muscles are made up of two types of fibre. These fibres have connections between them that lock and unlock during muscle contraction and relaxation. These connections are controlled by a biochemical pathway within the cell, which is partially driven by the presence of calcium ions. The concentration of calcium ions is higher in the fluid surrounding muscle cells than it is inside the cells, so calcium tends to diffuse into the cell. High calcium levels inside the cell drive the biochemical pathway in the direction that maintains muscle contraction. To relax, muscle cells must expel the calcium ions from the cell and this requires energy molecules to pump them across the cell membrane. After a body has died, the chemical reaction producing these energy molecules is unable to proceed because of a lack of oxygen. The cells no longer have the energy to pump calcium out of the cell and so the calcium concentration rises, forcing the muscles to remain in a contracted state. This state of muscle stiffening is known as rigor mortis and it remains until the muscle proteins start to decompose. Cells eventually die and the body loses its capacity to fight off bacteria. The cells' own enzymes and bacterial activity cause the body to decompose - muscles lose their stiffness. * Brain cells can die if deprived of oxygen for more than three minutes. Muscle cells live on for several hours. Bone and skin cells can stay alive for several days. * It takes around 12 hours for a human body to be cool to the touch and 24 hours to cool to the core. * Rigor mortis commences after three hours and lasts until 36 hours after death. * Forensic scientists use clues such as these for estimating the time of death.