The neural and chemical control of heart rate

• Chemoreceptors-

  • detect increases in blood co2 and acidity levels

  informs the cardiac control centre

  • causes the sympathetic nervous system to increase heart rate
  • impulses are sent down the accelerator nerve
  • causes the release of adrenaline (increased strength of impulse ,increased stroke volume ) and nor adrenaline (speeds up impulse,increased heart rate )
  • which acts on the SA node.
• baroreceptors

  • detect increases and decreases in blood pressure

  cardiac control centre

  • Inform the parasympathetic nervous system which decreases heart rate
  • impulses sent down the vagus nerve
  • causes the release of acetylcholine-sloesdoen the impulse decreases heart rate
  • acts on the SA node