Relay neurone the nerve cell that caries signals from the sensory neurone to the motor neurone (In the CNS!)

Sensory neurones carry signals as electrical impulses from the receptors in sense organs to the CNS

Motor neurone the nerve cell that carries signals from the CNS to the effector muscles or glands

Effectors these are muscles and glands they respond in different ways. Muscles contract in response where as glands secrete hormones

Reflexes

Reflexes bypasses the conscience brain completely when a quick response is essential

Help prevent injury, automatic responses to certain stimuli

For example if someone shines a bright light in your eye your pupils automatically get smaller to reduce the amount of light let in, also if you get a shock your body releases the hormone adrenaline automatically

The passage of information in a reflex (from receptor to effector) is called a reflex arc.

Synapses

Synapses connect neurones

The connection between two neurones is called a synapse

The nerve cell is transferred by chemicals which move across the gap

These chemicals then set off a new electrical signal in the next neurone