Nerve cell growth. Fluorescent light micrograph of a PC12 cell following stimulation by nerve growth factor. The cell body contains the nucleus (green). The initially spherical cell has formed long branching extensions called neurites (yellow and pink). These neurites would form the axons and dendrons that connect nerve cells and transmit nerve impulses around the body, and the brain and spinal cord. PC12 cells are derived from a tumour of the adrenal gland (pheochromocytoma). Research into curing spinal paralysis uses nerve tissue cultures to investigate neural regeneration. Magnification: x980 when printed 10cm wide.