The human brain has approximately 100 billion nerve cells. Nerve cells are also found in the spinal cord. Together, the brain and spinal cord make up the central nervous system (CNS). Each nerve cell is called a neuron, and this is comprised of a cell body directing its activities; dendri...
whereas the tail is hydrophobic, or repellent to water. Phospholipids are therefore called amphiphilic. Because of this dual nature of phospholipids, many types arrange themselves into two layers in a