By the age of eighteen our brain stops growing.
From that age forward it begins to lose more than 1,000 brain cells every day. Only two percent of our body weight is occupied by our gray matter, but is uses up to 20% of our overall energy output (it needs carbohydrates). Our brain works continuously and never rests, even when we’re asleep. Aside from producing REM dreams, our brain works overtime to replenish its ability to function normally during our daytime waking hours.
There are more than 600 individual skeletal muscles and 206 bones in our body.
If all 600+ muscles contracted and pulled in the same direction, we could lift over twenty tons of resistance. Additionally, the adult skeleton is composed of 206 bones, but at birth an infant skeleton contains approximately 350 bones. Over time, some of the 350 bones fuse together and eventually grow to the 206 adult figure.