Science & Halloween : Death

An inevitable part of life’s programme

Only the most primitive organisms, the so-called single cell “animals”, i.e., the protozoans -and not even all of them- are potentially without death as they grow, divide, separate and repeat this cycle over and over again. Normal cells of mammalian tissues in isolated cultures will also continue to “live” and divide, sometimes long after the host’s body they originated from has succumbed. The difference to the protozoan life forms, however, is that these mammalian cells eventually appear to run out of divisions. It is as if death was programmed into their genetic code through the gradual shortening of so-called telomeres present at the ends of the chromosomes. Human cells can divide, and divide, and divide again, perhaps fifty times or a little more, and then they come to the end of the road, so-to-speak. Although human skin cells will be viable for up to a couple of days after a person has died, the often heard opinion that fingernails and body hair continue to grow after death is an illusion brought about by the fact that a dead body loses water and actually shrinks. Thus, the harder structures like fingernails and hair become more prominent and appear to grow.

Food Pyramid

It’s not the same as the “food web” or “food chain”

Even well-seasoned biologists, as has happened once at a conference that I attended in Makarska (Croatia), can make mistakes and confuse the two terms “food pyramid” and “food web”. Food webs can be inextricably complicated and contain all possible interactions between various plant and animal species. They not only involve which kinds of food the individuals of a species accept, but also how the food species interact with each other, what roles the enemies, parasites and disease causing organisms play, whether immature and adult individuals have different food preferences and face attacks from different organisms. Even what happens to the dead organisms enters into a food web. Such extraordinarily complex relationships are extremely hard to model, unless one focuses on a food web with very few “players” in it, for example Antarctic springtails (tiny arthropods, which co-exist with less than a handful of other species on the southern continent).

Monkey Business

Overworked and Overexcited: Heart Attack

Many a human life is claimed by a heart attack. Heart attacks are some of the main causes of premature deaths. Job and family-related stresses are implicated; genetic disposition, social habits and diets are held responsible and even a “broken heart” (as I know from personal experience) can affect your life-sustaining pump in a bad way. How? There is in the brain an almond-sized structure called the amygdala. That structure is the seat of strong emotions like fear, pleasure and sadness. Constant activation of the amygdala, let’s say by an intense feeling of disappointment, leads to an increased risk of cardiac vascular dysfunction or disease, which can ultimately lead to someone “dying of a broken heart”.