Radio Shows | Flora and Fauna | mp3 … wma … wav

I know you've heard about the flora and fauna of different ecosystems but what about organisms hosted by the human body?

Hmmm… before or after my shower?

Believe it or not, it doesn't matter much.

That's disgusting!

The human body is a veritable ecosystem of bacterial and other microbial populations. They occupy every conceivable niche on the surface of our body as well as our gastrointestinal tract, urinary track, oral cavity and nasopharynx.

Depending on the location, they're all different but mostly they're bacteria and we call them normal flora.

We're colonized by microbes right from birth but there are areas of the body that remain sterile like the blood, brain, and lungs. If any end up in those places, it's a serious medical condition and an indication of underlying disease.

You probably wouldn't guess that the number of bacteria actually exceeds the cells that make up our bodies. We are composed of about 100 trillion human cells. Amazingly, we host more than 10-20 times that number of bacteria.

Bacterial populations are the highest in the large intestine where there may be more than a trillion bacteria per milliliter of intestinal fluid. They're also on and under the skin and our mouths are also a cornucopia of microbial life with over 500 different types.

Whoa, give me some mouthwash!

Our normal flora has adapted to life on humans and is actually beneficial to us. For example, E. coli in the colon makes vitamin K which is essential for blood clotting. Normal flora can also kill invading pathogens so they don't colonize and produce disease.

Our relationship with our normal flora is much like an ecosystem — when everything is "in check" both sides benefit. When that balance is upset and either a certain bacteria overgrows or a person's immune system declines, disease can emerge.

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