control of the heart

• What type of muscle is cardiac muscle?

  Myogenic
• 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 are the three stages of the cardiac cycle mentioned?

  Atrial systole, ventricular systole, diastole
• What triggers atrial systole?

  A wave of depolarization from the SAN
• What is the function of the sinoatrial node (SAN)?

  It releases a wave of depolarization
• Where is the sinoatrial node located?

  In the right atrium
• What is the atrioventricular node (AVN) responsible for?

  Releasing a wave of depolarization
• What separates the atria from the ventricles?

  A layer of non-conductive tissue
• What is the bundle of His?

  Conductive tissue in the heart
• What do Purkinje fibers do?

  Conduct depolarization through the ventricles
• Why is the contraction of the ventricles initiated at the apex?

  To maximize blood ejection from the heart
• What is the advantage of the non-conductive tissue in the heart?

  It allows time for atrial contraction
• What part of the nervous system controls heart rate?

  The autonomic nervous system
• What is the role of the medulla oblongata in heart rate control?

  It coordinates heart rate adjustments
• How does the sympathetic nervous system affect heart rate?

  It increases the heart rate
• What effect does the parasympathetic nervous system have on heart rate?

  It decreases the heart rate
• What are the two key stimuli that affect heart rate?

  Changes in pH and blood pressure
• Where are the chemoreceptors located?

  In the aorta and carotid artery
• What happens when blood pressure is too high?

  It stretches the blood vessels
• What is the response when blood pressure is too low?

  Increase in heart rate
• How does a decrease in pH affect heart rate?

  It triggers an increase in heart rate
• What is the role of baroreceptors?

  Detect changes in blood pressure
• What happens to enzymes if acidic molecules are not removed quickly?

  They can denature
• What is the flow of information in response to increased blood pressure?

  • Stimulus: High blood pressure
  • Receptors: Baroreceptors in aorta and carotid artery
  • Coordinator: Medulla oblongata
  • Effector: SAN
  • Response: Decreased heart rate
• What is the flow of information in response to decreased blood pressure?

  • Stimulus: Low blood pressure
  • Receptors: Baroreceptors in aorta and carotid artery
  • Coordinator: Medulla oblongata
  • Effector: SAN
  • Response: Increased heart rate
• What is the flow of information in response to decreased pH?

  • Stimulus: Decreased pH
  • Receptors: Chemoreceptors in aorta and carotid artery
  • Coordinator: Medulla oblongata
  • Effector: SAN
  • Response: Increased heart rate
• What are the key components involved in the cardiac cycle control?

  • SAN: Releases depolarization wave
  • AVN: Relays depolarization to ventricles
  • Bundle of His: Conducts impulses down septum
  • Purkinje fibers: Conduct impulses through ventricles
• What are the consequences of high blood pressure?

  • Damage to artery linings
  • Risk of blood clots
  • Potential heart attack or stroke
• What are the consequences of low blood pressure?

  • Insufficient oxygen supply
  • Inadequate waste removal
  • Risk of toxin buildup
• What happens during high respiration affecting blood pH?

  • Increased carbon dioxide
  • Increased lactic acid
  • Potential enzyme denaturation
• What is the importance of the delay caused by non-conductive tissue?

  • Allows atria to fully contract
  • Ensures ventricles are filled with blood
• How does the heart respond to exercise?

  • Increased heart rate
  • Enhanced blood flow to muscles
  • Removal of carbon dioxide and lactic acid