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Heart Physiology and Cardiac Function

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Terms in this set (27)

  • What does the T wave represent on an ECG?
    The T wave represents ventricular repolarization.
  • What does the QRS complex represent on an ECG?
    The QRS complex represents ventricular depolarization.
  • What does the P wave represent on an ECG?
    The P wave represents atrial depolarization.
  • What is a ventricular septal defect?
    A ventricular septal defect is a hole in the wall between the two ventricles.
  • What is an atrial septal defect?
    An atrial septal defect is a defect in the wall between the two atria.
  • Which vessels return oxygenated blood from the lungs to the heart?
    The pulmonary veins return oxygenated blood from the lungs to the heart.
  • Which ventricle pumps blood into the pulmonary circuit?
    The right ventricle pumps blood into the pulmonary circuit.
  • What are the external flaps on the outside of the atria called?
    The auricles are the external flaps on the outside of the atria that allow some extended volume.
  • Which channels are responsible for the plateau phase in cardiac action potentials?
    Calcium channels are responsible for the plateau phase.
  • What is the name of the vein formed by the veins of the heart muscle that empties into the right atrium?
    The veins merge to form the coronary sinus which empties into the right atrium.
  • What is the fetal lung bypass from the pulmonary trunk to the aorta called, and what does it become after birth?
    The fetal lung bypass is the ductus arteriosus, which closes at birth and becomes the ligamentum arteriosum.
  • What are the stabilizing strings of the tricuspid and bicuspid valves called?
    They are called chordae tendineae.
  • What are the muscular ridges inside the ventricles called?
    The muscular ridges inside the ventricles are called trabeculae carneae.
  • Are the AV valves open or closed during ventricular systole?
    During ventricular systole, the AV valves are closed.
  • Are the semilunar valves open or closed during ventricular systole (ventricular ejection phase)?
    During ventricular systole, the semilunar valves are open.
  • Are the semilunar and AV valves open or closed during isovolumetric relaxation?
    During isovolumetric relaxation, both the semilunar valves and AV valves are closed.
  • Where does the heartbeat originate and what is its inherent rate?
    The heartbeat originates from the sinoatrial (SA) node with an inherent rate of approximately 75 beats per minute.
  • If the SA node fails, which node maintains the heartbeat and at what rate?
    The atrioventricular (AV) node maintains the heartbeat at approximately 40-60 beats per minute.
  • What keeps the heart rate lower than the intrinsic rate and which nerve maintains this?
    The parasympathetic nervous system keeps the heart rate lower, maintained by the vagus nerve.
  • What does absence of a P wave before the QRS complex indicate?
    It indicates the sinoatrial (SA) node is not functioning.
  • What is atrial fibrillation?
    Atrial fibrillation is an arrhythmia with a fast, irregularly irregular rhythm.
  • What is a heart murmur?
    A heart murmur is the presence of an abnormal sound during the beating of the heart.
  • Does a heart murmur always indicate disease?
    False. A heart murmur does not always indicate disease and may not require a work-up.
  • How to calculate cardiac output?
    Cardiac output = heart rate × stroke volume.
  • Calculate cardiac output if heart rate is 75 bpm and stroke volume is 81 mL.
    Cardiac output = 75 × 81 = 6.08 liters per minute.
  • Calculate stroke volume if cardiac output is 5.347 L/min and heart rate is 72 bpm.
    Stroke volume = 5347 mL ÷ 72 = 74 mL per beat.
  • Calculate heart rate if stroke volume is 74 mL and cardiac output is 6.312 L/min.
    Heart rate = 6312 mL ÷ 74 = 85 beats per minute.