Here are seven interesting facts about our system that you will be amazed to know about.
Each man can produce 10 million new sperm cells in one day. That is enough to populate the planet in six months.
The body makes enough heat to boil 4 pints of water in only 30 minutes.
Human bones are stronger than concrete. Each cubic inch of a bone can take 8.6 tonnes of weight.
If you remove a human heart from the body, it will continue to beat for a limited time because it has its own electrical pulse.
One person produces enough saliva in their lifetime to fill two Olympic-size swimming pools.
The lungs have 300,000 blood vessels. If you laid them out, it would span a length of 1,500 miles.
The acid in a human stomach is so strong it can melt zinc.