Traditional lap pools are about 10 feet wide, though widths between 8 and 10 feet are common. (In competition pools, swim lanes are 2.5 meters wide, or about 8.2 feet.) You don't want to go too narrow with a lap pool.
The number of neurons in the brain varies dramatically from species to species. One estimate (published in 1988) puts the human brain at about 100 billion (10 11) neurons and 100 trillion (10 14) synapses.
Quick Answer. According to Neurogenetics at the University of Tennessee Health Science Center, the human body has 95 to 100 billion neurons or nerve cells. The brain alone has at least 85 billion of these cells, although estimates go as high as 1 trillion.