For approximately the first 3 hours after death the body will be flaccid (soft) and warm. After about 3-8 hours is starts to stiffen, and from approximately 8-36 hours it will be stiff and cold. The body becomes stiff because of a range of chemical changes in the muscle fibres after death.
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.
24-72 hours after death — the internal organs decompose. 3-5 days after death — the body starts to bloat and blood-containing foam leaks from the mouth and nose. 8-10 days after death — the body turns from green to red as the blood decomposes and the organs in the abdomen accumulate gas.
What Happens One Hour After Death? At the moment of death, all of the muscles in the body relax (primary flaccidity ). The eyelids lose their tension, the pupils dilate, the jaw may fall open, and the joints and limbs are flexible.
Pupils dilate
When people die, their bodies relax. This impacts your eyes just as much as the rest of your body. As soon as the muscles that control your eye movement relax, the pupils dilate. This happens over a progression of several hours after death.
As the blood pools, patches appear on the skin within 30 minutes of death. About two to four hours postmortem, these patches join up, creating large dark purplish areas towards the bottom of the body and lightening the skin elsewhere. This may be less apparent on darker skin. This process is called livor mortis.
The immediate seconds and minutes after death
Muscles including sphincters relax which means dying people may defecate or urinate.
For the first few minutes of the postmortem period, brain cells may survive. The heart can keep beating without its blood supply. A healthy liver continues breaking down alcohol. And if a technician strikes your thigh above the kneecap, your leg likely kicks, just as it did at your last reflex test with a physician.
The first visible change to the body—occurring 15 to 20 minutes after death—is pallor mortis, in which the body begins to pale. Pallor mortis occurs because blood stops moving through the capillaries, the smallest of the body's blood vessels.
After someone dies, it's normal to see or hear them. Some people also reporting sensing the smell or warmth of someone close to them, or just feel a very strong sense of their presence. Sometimes these feelings can be very powerful. They may be comforting but also feel disturbing.
What happens when someone dies? In time, the heart stops and they stop breathing. Within a few minutes, their brain stops functioning entirely and their skin starts to cool. At this point, they have died.
Decomposition can divide into five stages – fresh, early decomposition, advanced decomposition, skeletonization, and extreme decomposition. The early decomposition phase begins with the onset of skin slippage and hair loss. These changes usually begin from the first day after death to up to five days post-mortem.
For approximately the first 3 hours after death the body will be flaccid (soft) and warm. After about 3-8 hours is starts to stiffen, and from approximately 8-36 hours it will be stiff and cold. The body becomes stiff because of a range of chemical changes in the muscle fibres after death.
Putrefaction (4-10 days after death) – Autolysis occurs and gases (odor) and discoloration starts.
Rigor mortis is the post mortem stiffening/ rigidity of the body. It results from a decrease in levels of adenosinetriphosphate (ATP) beyond critical levels. When a person dies, calcium ions flood muscle fibers due to the loss of integrity of the muscle cells.
An accurate time of death also can help rule out possible suspects who may have been somewhere else when the death occurred and a more general time range could create a larger window for someone's alibi. This information can be used in court to establish a case.
Lung - 4 to 6 hours. Heart - 4 hours. Liver - 24 hours.
After death, there is are no reflexes of the pupils to light and the cornea also loses its reflex. The cornea of the deceased also become cloudy after two hours of death. Besides that, the pressure in the eyes start to decrease and the eyeballs become flaccid before it they sink into the orbits of the eyes.
Normally there is no measurable, meaningful brain activity after the heart stops beating. Within two to 20 seconds the brain “flatlines.”
The first organ system to “close down” is the digestive system. Digestion is a lot of work! In the last few weeks, there is really no need to process food to build new cells. That energy needs to go elsewhere.
By three days, internal organs have decomposed. From three to five days after death, the body will begin to bloat from gasses produced from internal decomposition. The body could actually double in size and turn a greenish color. Extremely unpleasant and long-lasting odors called putrification begins.
Eventually, the gases and liquefied tissues purge from the body, usually leaking from the anus and other orifices and frequently also leaking from ripped skin in other parts of the body. Sometimes, the pressure is so great that the abdomen bursts open.
A small incision is made in the lower part of the deceased's abdomen and a trocar (a sharp surgical instrument) is inserted into the body cavity. The organs in the chest cavity and the abdomen are then punctured and drained of gas and fluid contents.
Hospice nurse here. I've never seen bleeding, per se, but I've seen reddish-brown discharge in the mouth or nose, that looks like blood. This is known as PURGE FLUID. Gases form throughout the body after death.