Control of heart rate

Cards (26)

  • What does myogenic mean in relation to cardiac muscle?
    It can contract and relax on its own
  • How is the rate of cardiac muscle contraction controlled?
    By the nervous system
  • What triggers atrial systole?
    Wave of depolarization from SAN
  • What is the function of the atrioventricular node (AVN)?
    Releases a wave of depolarization
  • Why is there a layer of non-conductive tissue between the atria and ventricles?
    To prevent direct depolarization to ventricles
  • What is the role of the bundle of His?
    Conducts depolarization to ventricles
  • What are Purkinje fibers also known as?
    Perkin fibers
  • How does the contraction sequence in the ventricles occur?
    Apex contracts first, then outer walls
  • Why is the contraction sequence in the heart compared to squeezing toothpaste?
    To maximize blood ejection from the heart
  • What is the advantage of the slight delay caused by non-conductive tissue?
    Allows atria to fully contract and fill ventricles
  • What part of the nervous system controls heart rate?
    Autonomic nervous system
  • What is the role of the medulla oblongata in heart rate control?
    Coordinates heart rate through nervous impulses
  • How does the sympathetic nervous system affect heart rate?
    Increases heart rate
  • What effect does the parasympathetic nervous system have on heart rate?
    Decreases heart rate
  • What are the two key stimuli that affect heart rate?
    Changes in pH and blood pressure
  • Where are the chemoreceptors located?
    Aorta and carotid artery
  • What happens when blood pressure is too high?
    Triggers action potential in pressure receptors
  • What is the response when blood pressure is too low?
    Increases heart rate via sympathetic nervous system
  • What happens when pH decreases in the blood?
    Increases heart rate to remove acids
  • What is the role of baroreceptors?
    Detect changes in blood pressure
  • What is the effect of increased carbon dioxide on heart rate?
    Increases heart rate to remove CO2
  • What is the flow of information in the heart rate control process?
    1. Stimulus detected by receptors
    2. Coordinator: Medulla oblongata
    3. Impulses sent via sympathetic or parasympathetic nervous system
    4. Effector: SAN in cardiac muscle
    5. Response: Adjusted heart rate
  • What are the differences in responses to high and low blood pressure?
    High Blood Pressure:
    • Detected by baroreceptors
    • More impulses to medulla oblongata
    • Increased parasympathetic activity
    • Decreased heart rate

    Low Blood Pressure:
    • Detected by baroreceptors
    • More impulses to medulla oblongata
    • Increased sympathetic activity
    • Increased heart rate
  • How does the body respond to decreased pH in the blood?
    1. Detected by chemoreceptors
    2. More impulses sent to medulla oblongata
    3. Increased sympathetic nervous system activity
    4. Increased heart rate to remove acids
  • What are the key components involved in the cardiac cycle control?
    • Sinoatrial Node (SAN)
    • Atrioventricular Node (AVN)
    • Bundle of His
    • Purkinje Fibers
  • What is the significance of the delay caused by non-conductive tissue in the heart?
    • Allows atria to fully contract
    • Ensures ventricles are filled with blood
    • Prevents simultaneous contraction of chambers