Neurons are information- processing units in the central nervous system that receive and transmit information. It is made up of an axon, dendrites and a cell body. The nucleus and cytoplasm are contained in the cell body. The axon starts from the cell body, dividing into smaller branches and then ends at the nerve terminals. The dendrites also branch from the cell body, receiving information from the other neurons. Axons from other neurons forms synapses at their ends, which cover the cell body and dendrites.(Myers, 2013)Neurons send messages by passing impulses through their axons. The axons have different lengths. They range between a fraction of an inch and three feet or more. A layered myelin sheath, which covers the axon, enables information to be transmitted fast through the axon. The sheath consists of specialized cells in the brain, known as oligondrocytes and others in the peripheral nervous system called Schwann cells. Nerve impulses occur through the closing and opening of ion channels.
The ion channels are molecular tunnels filled with water that go through a cell membrane. They allow for permeability selectively, enabling the entering and leaving of ions or small molecules into the cells. An electrical current producing change of voltage in the cell membrane of the neuron is made. The generation of an impulse is dependent on the charge difference of the inside and outside of the cell. The neuron changes to a positive charge creating a reversal of the electric potential at the cell membrane. The change is known as an action potential.
It goes through the axon membrane at a speed of hundreds miles per hour, enabling a neuron to fire many impulses per second. The
References: Myers, D. G. (2013). Psychology in Modules (10 ed.). New York: Worth Publishers