central and peripheral

• Autonomic nervous system is involuntary (self regulating
• Somatic nervous system is under conscious control
• Sensory neurons convert information from sensory receptors e.g eyes into neural impulses. When they reach the brain it is translated into sensations like visual input
• Relay neurons allow sensory neurons and motor neurons to communicate with each other, these are located wholly in the brain and spinal cord.
• Motor neurons form synapses with muscles and control their contractions
• Hormones are chemicals that are released by glands and circulate the bloodstream to target cells which have specifically shaped receptors for that hormone. Once enough receptor sites are stimulated by hormones, it results in a physiological reaction in the target ce
• Excitation - in the process of excitation an excitatory neurotransmitter will leave the presynaptic neurons via exocytosis and bind to the specifically shaped receptor on the postsynaptic neuron. This causes an electrical change in the membrane of that neuron, resulting in an excitatory postsynaptic potential, which is therefore more likely to fire the action potential.
• Inhibition - in the process of inhibition an inhibitory neurotransmitter binds to the specifically shaped postsynaptic receptor, causing an inhibitory postsynaptic potential, making it less likely that the neuron will fire the action potential. Therefore reducing the electrical activity in this region of the brain.
• Excitatory neurotransmitters such as noradrenaline are the nervous systems “on switches” causing the postsynaptic neuron to fire
• Inhibitory neurotransmitters such as serotonin are the nervous systems off switches which reduce the likelihood of the postsynaptic neuron firing.