Every neuron is made of a cell body (also called a soma), dendrites and an axon. Dendrites and axons are nerve fibres. There are about 86 billion neurons in the human brain, which comprises roughly 10% of all brain cells. The neurons are supported by
Neurons are connected to one another and tissues. They do not touch and instead form tiny gaps called
There are three classes of neurons: afferent neurons, efferent neurons, and interneurons.
Sensory neurons carry signals from sense organs to the spinal cord and brain.
Relay neurons carry messages from one part of the CNS.
Motor neurons carry signals from the CNS to muscles, motor neurons are connected to the relay neurons. The signal passes between the neurons via synapses. Synapses are microscopic voids between cells where chemicals are released from the axon terminal of one cell to specialized chemical receptors on the dendrite of the receiving cell.