Death is the last taboo for Western culture. We are surrounded by death and violence in films and videos, but we still cross the road to avoid speaking to a neighbour whose wife has died.

It seems we can deal with fictional death, as long as it is over quickly and we are not forced to dwell on the reality of our own mortality.

The BBC's Human Body series forces us to face it head on as it examines the end of the human story.

Death is not a single, instantaneous event. It is a gradual process as the body closes down. It is difficult to pinpoint when the process has ended. The body can still be breathing even though the brain has died.

Controversy

The programme controversially traces the final moments of Herbie, a German man living in Ireland who has been diagnosed with inoperable stomach cancer.

Herbie faces death

He was originally given two months to live, but has survived over a year when the BBC first meets him.

Herbie only realised he was ill when he collapsed at the wheel with stomach pain. He was rushed to hospital and the tumour was found.

Unlike Herbie, most people hide from death. But it wasn't always so. Presenter Robert Winston journeys to catacombs in Italy where 8,000 bodies are preserved.

He says understanding death can help to make it easier to face it.

Making the best of the end

Herbie says the reason he agrees to do the film is to show people that they can "make the best of the end of their life".

The Italian catacombs: the West did not always fear death

He receives visits from hospice workers who tell him he can die without pain and in peace.

Although death appears to be the antithesis of birth, life and death are linked from the start. Even in the womb, some of the foetus' cells are dying.

The foetus' fingers are formed by the cells around them being chipped away in much the same way as a sculptor forms his work.

Professor Winston says death comes after humans have fulfilled their function of giving birth and keeping the gene pool going.

Heart disease

The biggest killer in the West is heart disease. The heart pumps 7,500 litres of blood around the body every day.

25% of deaths are caused by heart failure

Blockages slow its movement and can lead to heart attacks. Without blood, the heart fails within five minutes and the breathing stops.

Yet heart bypass surgery can be performed when the heart has been stopped. The body is not clinically dead until the brain stem stops functioning.

This controls body temperature, the heart beat, breathing and blood pressure.

Herbie can sense when he is ready to die. His tumour begins to push against other organs, such as the kidneys, throwing the body out of balance and causing him great pain. His cheeks become hollow. He wants to die. He is 63 years old.

Near-death experiences

The best way to get an insight into what happens when the brain dies is to talk to people who have had near-death experiences. Almost all say they saw a tunnel of light and felt elated when they lost consciousness.

But experiments have shown that fighter pilots subjected to extreme G-forces also see a tunnel of light and feel a sense of headiness.

Robert Winston believes this is because the brain has momentarily become starved of oxygen, causing the neurons which control the vision to fire at random.

He says the feeling of elation may be due to the body releasing opiate-like substances to deal with the pain, causing hallucinations and emotional changes.

Singing

Herbie does not believe in an after-life, but he says he is not afraid of death. His breathing becomes difficult, but he can still hear the visitors who gather round his bed and his wife.

A neighbour and his daughter arrive and they sing an Irish song to Herbie and wish him well. Herbie's breathing becomes noisy and he rattles and shakes.

His nurse says this is common and that he is not in pain. His body gives out as he lies beside his wife.

She says it is a relief that he is no longer in pain. She cannot think of her own grief.

The constant cycle of life

Herbie leaves a message for his funeral. He says he wants his neighbours to live together in peace and to hold him in their memories.

People's lives live on in the mind and the atoms that go to make the human body are recycled into what Robert Winston calls "the endless repeating cycle from life to death".

The End of Life is the final episode of The Human Body. The series is accompanied by a video, a CD Rom and a book - all available from the BBC.