Nervous Control

• what are baroreceptors


  detect changes in pressure

  • located in carotid sinus and walls of the heart
• what are chemoreceptors


  detect changes in pH (CO2 and O2 levels)

  • located in walls of the heart, carotid and aortic arteries, and medulla oblongata
• controlled by reflecting arcs originating in sensory receptors
• receptors pass the sensory information (via sensory neurones) to the cardiovascular centre (in medulla oblongata)
• which two nerves work antagonistically to control heart rate

  vagus (parasympathetic) and sympathetic
• what are those nerves a part of

  autonomic nervous system

  • lead from cardiovascular centre to pacemaker cells of SAN
• what is the difference between vagus and sympathetic nerve

  vagus

  • parasympathetic
  • direct cardiovascular centre to SAN
  • inhibitory so slows heart rate

  sympathetic

  • sympathetic
  • centre -> spinal cord -> SAN
  • excitatory so increases heart rate