Neurons

• Sensory:

  Found in the receptors eg eyes, ears, tongue and skin.

  Carry nerve impulses to the spinal cord and brain. When these nerve impulses reach the brain, they are translated into 'sensations' e.g vision hearing, taste and touch. Not all sensory neurons reach the brain as some neurons stop at the spinal cord, allowing for quick reflex actions.
• Motor:

  Found in the CNS and controls muscle movement.

  When motor neurons are stimulated, they release neurotrasmitters that bind to the receptors on muscles or trigger a response, which lead to movement.
• Found between the sensory input and motor response. Relay neurons are found in the brain and spinal cord: allow sensory and motor neurons to communicate.
• Dendrites receive signals from other neurons or from sensory receptor cells. The dendrites are typically connected to the cell body.
• cell body; ‘control centre’ of the neuron, as it contains the nucleus.
• Axon is a long slender fibre that carries nerve impulses in the form of an electrical signal (action potential) away from the cell body towards the axon terminals, where the neuron ends.

  Most axons are surrounded by a myelin sheath (expect for relay neurons) which insulates the axon so the electrical impulses travel faster along the axon.

  The axon terminal connects the neuron to other neurons using a processes called synaptic transmission.
• Some neurotransmitters are excitatory and some are inhibitory. Excitatory neurotransmitters makes the post synaptic cell more likely to fire, inhibitory neurotransmitters makes them less likely to fire. excitatory neurotransmitter binds to the post-synaptic receptors, cause an electrical charge in the cell membrane which results in excitatory postsynaptic potential and makes the post-synaptic cell more likely to fire. If an inhibitory neurotransmitter binds to the post-synaptic receptors, it will result in an inhibitory post-synaptic potential makes the post-synaptic cell less likely to fire.