The science of death

By Zoë Gamble

Humans have a morbid curiosity about death. Different cultures have different beliefs and traditions when it comes to ‘passing on’. And, throughout history, humans have tried find ways to extend life, or to ensure life after death.

 

A bit about culture…

Marvellous Mummies

Ancient Egyptians had many beliefs with regards to the afterlife. For example, that only a person with a light heart could earn a space on “Ra’s boat” and enter paradise, and that after death, your soul would split up into two parts, the ba and ka. What a person leaves behind after death, their body, was preserved.

Egyptian Mummy held in the British Museum.  Photo: Paul Hudson (CC-BY)

Egyptian Mummy held in the British Museum. Photo: Paul Hudson (CC-BY)

This is where modern day scientists and Ancient Egyptians agree – mummification is a great way of preserving a body. In this process, organs were removed first as they decompose quickly, and were dried out using natron. Natron is a natural salt, and chemically breaks down grease. Some scientists believe that the Ancient Egyptians also made glue from gelatin which was used to make the adhesive in paint used to decorate many things in the tomb including the sarcophagus.

Day of the Dead

In Mexico, the Day of the Dead is a bank holiday on November 1st. People gather to remember friends and relatives who have passed on. There are many different traditions observed throughout Mexico, and other parts of the world. Some people like to make the favourite meals of their lost loved ones, while others may even get tattoos.

Day of the Dead celebration

‘Alfeniques’ – sugar candy that allude to the Day of the Dead celebrations in Mexico. Photo: Tomascastelazo (CC-BY-SA)

A bit about death statistics…

Date of death?

“Your date of demise is 29th April 2072”, I was told by an online ‘Death Timer’ http://www.deathtimer.com/ Now you’ve got to take this with a pinch of salt of course, although this does estimate me living to a grand old age of 83. However, some of the factors it uses to make its estimations are good indicators – where you live in the world, your BMI, whether you smoke or drink, and whether you are male or female. If you live in the UK for example, you are more likely to live longer than someone from Nigeria, or Moldova. On the other hand, statistics show that people living in Japan and Switzerland have higher life expectancies than those in the UK. Statistically, women outlive men. While we can’t control what gender we were born, and to a certain extent what part of the world we grow up in, we should have some control over what food we eat, and how much, whether we choose to smoke or drink alcohol, or how well we look after ourselves.

Death Statistics

You might be worried about being knocked down by a car, or catching swine flu, but you should be more worried about the silent killers – the leading causes of death are cardiovascular disease and cancer. Check out this image from The Guardian showing the causes of death in England and Wales in 2010.

You’ll notice that out of the total 493,242 deaths in England and Wales in 2010, only 142 were swine flu! This is in comparison to the 158,084 deaths that were caused by circulatory disorders. 655 people died from falling down the stairs, and 96 cyclists were killed in road traffic accidents. However, cancers and neoplasms caused 141,446 deaths over the year.

A bit about our cells dying…

Amazing Apoptosis

We need new cells all the time, for normal growth and repair. So, the cells that have come to the end of their usefulness need to be removed. Cells are quite self-sacrificing. When they receive signals that they are no longer needed, they quickly undergo apoptosis (programmed cell death) for the good of the organism. When the cell dies this way, there is no damage to the surrounding cells. About 60 billion cells die this way every day in an adult. However, this process can sometimes go wrong, and we call this ‘necrosis’.

Nasty Necrosis

Necrosis is similar to apoptosis except that it is not planned. It results in the premature death of cells and can harm our other cells. Necrosis can be caused by external factor such as toxins or trauma, and is always disadvantageous to the organism. All the cells in our body have to die one day – let’s hope they pass on peacefully via apoptosis and not necrosis!

A bit about prolonging life…

Troubles with telomeres

The cells in our body are constantly dividing, as we grow, age, and repair damage. Chromosomes, which contain the genetic material within our cells, are capped with structures called telomeres which protect them. Every time a cell divides, a small part of the telomere is lost, leading to a loss of integrity. This loss of telomere integrity can eventually lead to cell death, and is a contender for one of the causes of ageing.

Telomeres capping the end of a chromosome

Telomeres capping the end of a chromosome. Image: Samulili (CC-BY-SA)

Short telomeres have been linked to age related diseases. However, having a healthy, active, stress-free lifestyle has been linked to longer telomeres. So, that’s one way to help remain youthful for as long as possible (ok – it’s what we all knew anyway).

Mighty Mice

mightymouse

Mightymouse. Image: Public Domain

The Methuselah Foundation is an organisation dedicated to extending healthy human life. Since 2003 they have presented the ‘MPrize’ to researchers working on different techniques to extend the lives of mice. One is the longevity prize, for the team that breaks the world record for the oldest ever mouse. The current record is held by the team who altered the genes of a mouse which then lived for 1,819 days. About 3 years, or 1,096 days is the most a mouse would naturally live in a lab.

The other is the rejuvenation prize. This involves taking an older mouse, and attempting to delay aging. The most successful technique to date is calorific restriction. This is where the amount of food available is restricted, but not so much that it causes malnutrition. The average life span of mice in the latest study was 1,356 days. Limiting the amount of calories consumed appears to be an effective way, across many species, of decreasing the chance of, and delaying the onset of age-related diseases.

For more information, including why mice are used, and references, see the MPrize website.

Takeaway lessons…

Live well, be good to your body….be excellent to each other and party on dudes!
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Posted in Biology