Nerve cells. Computer artwork of nerve cells (neurons) forming a network, such as that found in the brain or spinal cord. Each nerve cell has several long processes called dendrites, which are responsible for receiving signals from other nerve cells. Similar structures, called axons, are used to transmit signals. In this way, information and commands are transmitted around the body. In the brain, billions of connections between nerve cells are responsible for the immense processing power, memory and reasoning ability of the human brain. The central nerve cell body can vary in size from 4100 microns (thousandth of a millimetre) across.