Nerve nets

• Where can nerve nets be found?

  -simple organisms such as Hydra

  -the sensory receptors respond to a limited range of stimuli, and the number of effectors is relatively small
• Describe the features of a nerve net.?

  -contains one type of nerve cell

  -nerve cells have short extensions and connect to other nerve cells in a net-like structure, which branches in several different directions

  -neurones are unmyelinated, so responses are slow

  -the degree of response is dependent on the strength of the stimulus and how many receptors are stimulated
• Summarise what a nerve net is.?

  -nervous system in Hydra

  -sensory receptors in nerve nets respond to a limited range of stimuli

  -small number of effectors

  -neurones are unmyelinated and joined by short extensions

  -responses are slow

  -nerve cells branch in several different directions