It is dangerous to attempt a high-energy requiring exercise such as sprinting at the end of a workout. The end of the workout is known as a cool down period, in this period, it is wise to exercise with the intent to stop.
It is usually the time to stretch muscles so they are not sore the next day.
Well if you're referring to the human body, our cells make up a lot of everything we're made of. Muscles, organs, bones, blood, skin, etc. Biologically speaking, there's a lot to the human body besides organs. Sorry if this isn't very helpful.
