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Heart Anatomy and Physiology - Chapter 18

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Termini in questo insieme (26)

  • Position of the heart in the thoracic cavity
    The heart is located in the mediastinum, between the lungs, posterior to the sternum, and above the diaphragm.
  • Four chambers of the heart
    The heart has two atria (right and left) and two ventricles (right and left).
  • Coronary sulcus
    A groove on the heart's surface that separates the atria from the ventricles and contains coronary blood vessels.
  • Anterior and posterior interventricular sulci
    Grooves that mark the boundary between the right and left ventricles on the front and back of the heart.
  • Function of heart septa
    The septa separate the right and left sides of the heart to prevent mixing of oxygen-rich and oxygen-poor blood.
  • Atrioventricular (AV) valves
    Valves between atria and ventricles (tricuspid on right, mitral on left) that prevent backflow during ventricular contraction.
  • Semilunar valves
    Valves (pulmonary and aortic) located at the exits of ventricles that prevent backflow of blood into the heart after ejection.
  • Layers of the pericardium
    Includes the fibrous pericardium (outer tough layer) and serous pericardium (parietal and visceral layers) with the pericardial cavity between them.
  • Myocardium and intercalated discs
    The myocardium is the thick cardiac muscle layer; intercalated discs connect cardiac cells and allow synchronized contraction.
  • Endocardium
    A thin, smooth inner lining of the heart chambers that reduces friction for blood flow.
  • Right and left coronary arteries
    Arteries that supply oxygen-rich blood to the heart muscle; they branch off the ascending aorta.
  • Cardiac veins and coronary sinus
    Veins that collect oxygen-poor blood from the myocardium and drain into the coronary sinus, which empties into the right atrium.
  • Phases of cardiac muscle action potential
    Depolarization (Na+ influx), plateau (Ca2+ influx balances K+ efflux), and repolarization (K+ efflux).
  • Action potential generation in pacemaker vs contractile cells
    Pacemaker cells have spontaneous depolarization; contractile cells require stimulation and have a plateau phase; skeletal muscle cells lack plateau.
  • Significance of the plateau phase
    Prolongs contraction to allow efficient blood ejection and prevents tetanus in cardiac muscle.
  • Major blood vessels entering and leaving the heart
    Entering: superior/inferior vena cava (veins, oxygen-poor), pulmonary veins (veins, oxygen-rich). Leaving: pulmonary trunk (artery, oxygen-poor), aorta (artery, oxygen-rich).
  • Blood flow through the heart
    Blood flows: vena cava → right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary trunk → lungs → pulmonary veins → left atrium → mitral valve → left ventricle → aortic valve → aorta.
  • Heart as a double pump
    The right side pumps blood to the lungs (pulmonary circuit), and the left side pumps blood to the body (systemic circuit).
  • Parts of the cardiac conduction system
    Includes the SA node, AV node, AV bundle (Bundle of His), bundle branches, and Purkinje fibers.
  • SA node pacing role
    The SA node is the primary pacemaker due to its fastest spontaneous depolarization rate, setting the heart rhythm.
  • Autonomic nervous system role in cardiac function
    The ANS modulates heart rate and force of contraction via sympathetic (increases) and parasympathetic (decreases) inputs.
  • Waveforms in a normal ECG
    P wave (atrial depolarization), QRS complex (ventricular depolarization), T wave (ventricular repolarization).
  • ECG waveforms and cardiac events
    P wave: atrial contraction; QRS: ventricular contraction; T wave: ventricular relaxation.
  • Definition of cardiac cycle, systole, and diastole
    Cardiac cycle: one complete heartbeat; systole: contraction phase; diastole: relaxation phase.
  • Phases of the cardiac cycle
    Includes ventricular filling, isovolumetric contraction, ventricular ejection, isovolumetric relaxation.
  • Relation of ECG to mechanical cardiac events
    Electrical depolarization (ECG waves) precedes mechanical contraction and relaxation phases of the heart.