nervous system blah blah

• The central nervous system (CNS) consists of the brain and the spinal cord.

  The peripheral nervous system consists of the somatic nervous system (SNS) and autonomic nervous system (ANS)
• The somatic nervous system contains sensory and motor neurons.

  Sensory neurons take impulses from sense organs to the CNS.

  Motor neurons take impulses from the CNS to muscles and glands.
• The autonomic nervous system (ANS) consists of the sympathetic and parasympathetic nervous systems.

  Sympathetic and parasympathetic nervous systems work antagonistically (opposite).
• The sympathetic nervous system speeds up heart and breathing rate, whilst slowing down peristalsis and production of intestinal secretions
• The parasympathetic nervous system changes these in the opposite way, i.e. slowing down heart and breathing rate.
• In a converging pathway, impulses from several neurons travel to one neuron.

  This increases the sensitivity to excitatory of inhibitory signals.
• In a diverging pathway, impulses from one neuron travel to several neurons, affecting more than one destination at the same time.
• In a reverberating pathway, neurons later in the pathway link with earlier neurons, sending the impulse back through the pathway. This allows repeated stimulation of the pathway.