Interesting facts you need to know about your body
- Why it is not possible to sneeze with our eyes open?
Sneezing is the process by which our body tries to expel the unwanted matter which produces sensation in the mucous membrane of the nostril. While sneezing, our body feels a shock because the incoming air from the nostrils has an extraordinary high speed, about 165 km/hr. This causes a sudden vibration in our body and by reflex, our eyes close immediately.
- Why are human lips reddish in colour?
Human lips have a reddish colour because of the concentration of tiny capillaries just below the skin. The blood, in these capillaries is in normal case highly oxygenated and therefore quite red. This explains why the lips appear pale when a person is anemic or has lost a great deal of blood. It also explains why the lips turn blue in very cold weather. Cold causes the capillaries to constrict, and the blood loses oxygen and changes to a darker colour.
- Why do the people of hot countries have darker skin?
Skin colour depends mainly on a brown substance called melanin in the skin. Melanin protects the body from harmful ultraviolet rays in sunlight. People, whose ancestors have lived for hundreds of years in hot countries, have more melanin granules in their skin than people belonging to cool countries. As a result, people from hot countries have darker skins.
- Do we need energy to sleep?
Yes, indeed, although not too much. During eight hours of sleep, an average man burns up 520 calories (a calorie is the unit of energy produced). That is about half of what he would burn up if he were standing for all that time. And if he had been walking for eight hours, he would use almost 1,800 calories. While running, the average man burns up 600 calories an hour, almost nine times more than he would use during a night’s sleep.
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