The nervous system

Types of neurons

• Sensory neurons: carry messages from the peripheral nervous system to the brain and spinal cord
  
• Motor neurons: carry messages away from the brain and spinal cord (CNS) and to muscles and organs
• Connector/relay neurons: only found in the visual system, brain and spinal cord; receive messages from sensory neurons and pass messages to motor neurons

Parts of the neuron

• Cell body
• Dendrites: receive messages from other cells
• Axon: passes messages away from the cell body to other neurons, muscles or glands
• Action potential: electrical signal traveling down the axon
• Myelin sheath: covers the axon of some neurons and helps speed neural impulses
• Terminal buttons: form junctions with other cells

Synaptic transmission

• Electrical impulses travel down the axon (action potential…