Neurons

What are the three main types of neuron?

• sensory

• relay

• motor

What are sensory neurons?

• Found in receptor cells (e.g. eyes and skin)

• They carry nerve impulses to the spinal cord and brain

• These nerve impulses are translated into ‘sensations’ (e.g. vision and touch)

• Not all sensory neurons reach the brain, as some stop at the spinal cord, allowing for quick reflex actions

What are relay neurons?

• Found in between sensory input and motor output

• Found in the brain and spinal cord and allow sensory and motor neurons to communicate

What are motor neurons?

• Found in the central nervous system (CNS)

• When motor neurons are stimulated they release neurotransmitters that bind to the receptors on muscles to trigger a response

• Sends information to effectors e.g. muscles/glands

What are the parts of a neuron?

• Dendrites

• Axon

• Myelin sheath

• Axon terminal

What do dendrites do?

Receive signals from other neurons or from sensory receptor cells. Typically connected to the cell body (soma)

What is the axon?

A long, slender fibre that carries nerve impulse, in the form of an electrical signal known as action potential

What is a myelin sheath?

Most axons are surrounded by a myelin sheath which insulates the axon so that the electrical impulses travel faster along the axon

What is the axon terminal?

Connects the neuron to other neurons (or directly to organs), using a process called synaptic transmission