Control of heart rate

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Created by
sophia taylor

Cards (9)

  • Autonomic nervous system

    • System that controls involuntary actions of glands and muscles
    • 2 subdivisions: sympathetic & parasympathetic
  • Body's response to increase in blood pressure

    1. Baroreceptors send more impulses to cardioinhibitory centre in the medulla oblongata
    2. More impulses to SAN down vagus nerve via parasympathetic nervous system
    3. Stimulates release of acetylcholine, which decreases heart rate
  • Body's response to decrease in blood pressure
    1. Baroreceptors send more impulses to cardioacceleratory centre in the medulla oblongata
    2. More impulses to SAN via sympathetic nervous system
    3. Stimulates release of noradrenaline, which increases heart rate and strength of contraction
  • Body's response to increase in CO2 concentration

    1. Chemoreceptors detect pH decrease and send more impulses to cardioacceleratory centre of medulla oblongata
    2. More impulses to SAN via sympathetic nervous system
    3. Heart rate increases, so rate of blood flow to lungs increases = rate of gas exchange and ventilation rate increase
  • Myogenic

    Contraction of heart is initiated within the muscle itself rather than by nerve impulses
  • Nodes involved in heart contraction

    • Sinoatrial node (SAN): within the wall of the right atrium
    • Atrioventricular node (AVN): near lower end of right atrium in the wall that separates the 2 atria
  • Body's response to increase in blood pressure
    1. Baroreceptors send more impulses to cardioinhibitory centre in the medulla oblongata
    2. More impulses to SAN down vagus nerve via parasympathetic nervous system
    3. Stimulates release of acetylcholine, which decreases heart rate
  • Body's response to decrease in blood pressure
    1. Baroreceptors send more impulses to cardioacceleratory centre in the medulla oblongata
    2. More impulses to SAN via sympathetic nervous system
    3. Stimulates release of noradrenaline, which increases heart rate and strength of contraction
  • Body's response to increase in CO2 concentration

    1. Chemoreceptors detect pH decrease and send more impulses to cardioacceleratory centre of medulla oblongata
    2. More impulses to SAN via sympathetic nervous system
    3. Heart rate increases, so rate of blood flow to lungs increases = rate of gas exchange and ventilation rate increase