Brain + Autonomic

• What does control of HR involve?

  the brain and autonomic nervous system
• What does the SAN do?

  generates electrical impulses that cause the cardiac muscles to contract
• What does SAN stand for?

  Sinoatrial node
• How is the rate at which the SAN fires (IE HEART RATE) controlled?

  UNCONSCIOUSLY controlled by the medulla oblongata
• Where is the medulla oblongata?

  brain
• Why do animals need to alter their HR?

  To respond to internal stimuli

  eg to prevent fainting due to low blood pressure
• What detect stimuli?


  Pressure receptors and chemical receptors
• Describe baroreceptors?


  These are pressure receptors
• Where are baroreceptors found?

  In the aorta and the carotid arteries
• What are the carotid arteries?

  Major arteries in the neck
• What are baroreceptors stimulated by?

  High and low blood pressure
• Describe chemoreceptors?


  Chemical receptors
• Where are chemoreceptors found ?

  • Aorta
  • the carotid arteries
  • medulla
• What do chemoreceptors do?

  Monitor the oxygen level in the blood and carbon dioxide and pH (which are indicators of O2 level)
• Where are the electrical impulses from receptors sent?

  To medulla ALONG sensory neurones
• What does the medulla do?

  This is where the EIs from receptors are sent

  Medulla processes this info and sends impulses to the SAN along sympathetic or parasympathetic neurones
• What are sympathetic or parasympathetic neurones part of?

  The autonomic nervous system