Hormones and Nerves

Hormones and Nerves

Hormones and Nerves


  • Hormones are chemical messengers which travel the blood to activate target cells.
  • Hormones are released directly into the blood stream and are carried around the body until they reach their target organ/cells.
  • The target cells have the right receptors to respond to the hormone. Similarly, organs being affected are called target organs.
  • Hormones travel at “the speed of blood”. Their effects are long lasting.


  • Features of neurones:

  • The Dendrons connect with other neurones to enable electrical impulses to be passed along.
  • Neurones are very long which also speeds up the impulse. Connecting with other neurones slows the impulse down, so it is faster to have one long neurone instead.
  • The gap/connection between two neurones is called a synapse.
  • The nerve impulse is transmitted by chemicals called neurotransmitters. These diffuse across the synapse.
  • When the neurotransmitters reach the next neurone, they set off a new electrical impulse.

Differences between hormones and nerves