Facts about respiration
Although you can consciously control the rate of your breathing you cannot stop long enough to suffocate. As soon as the carbon dioxide in the body builds up to a certain extent, a message is sent to the brain. The brain then takes over and forces you to breathe. If you should hold your breath too long, you will simply pass out. Once you are unconscious, you automatically start breathing again.
When you sleep in a room with closed doors and windows, you do not sleep well because very little fresh air comes into the room, so that you do not get the needed amount of oxygen. Also it is unwise to sleep in a room with many green plants because they also breathe. During the day, when it is light, plants take in carbon dioxide and give up or expire oxygen. At night, when it is dark, plants reverse the
process and just as you do, they inhale oxygen and exhale carbon dioxide.
Facts about circulation
250,000,000 cells in the blood are destroyed and replaced daily.
All the liquid within the human body (and the body is more than 70% water) passes through the blood.
The entire over-all length of the veins, arteries and capillaries is about 12,000 miles.
Facts about the nervous system
Outgoing impulses can travel at a speed 200 miles per hour.
A person can live with only half of his brain functioning. The great scientist, Pasteur, suffered from a brain haemorrhage and was slightly paralyzed on one side. It was only after his death that doctors discovered that 50 per cent of his brain had been injured by that haemorrhage.
