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Heart Anatomy and Physiology

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Terms in this set (20)

  • Size, shape, location, and orientation of the heart

    The heart is roughly the size of a fist, conical in shape, located in the thorax between the lungs, slightly left of the midline, and oriented with the apex pointing down and to the left.

  • Coverings of the heart

    The heart is covered by the pericardium, which includes the fibrous pericardium and the serous pericardium (parietal and visceral layers).

  • Three layers of the heart wall

    Epicardium: outer protective layer; Myocardium: thick muscular middle layer responsible for contraction; Endocardium: inner lining that contacts blood.

  • Four heart chambers and their great vessels

    Right atrium (receives deoxygenated blood via superior/inferior vena cava), right ventricle (pumps to lungs via pulmonary trunk), left atrium (receives oxygenated blood via pulmonary veins), left ventricle (pumps to body via aorta).

  • Heart valves and their function

    Atrioventricular valves (tricuspid and mitral) prevent backflow into atria; Semilunar valves (pulmonary and aortic) prevent backflow from arteries into ventricles.

  • Mechanism of heart valve operation

    Valves open and close in response to pressure changes during the cardiac cycle, ensuring unidirectional blood flow.

  • Pathway of blood through the heart

    Blood flows: body → right atrium → tricuspid valve → right ventricle → pulmonary valve → lungs → left atrium → mitral valve → left ventricle → aortic valve → body.

  • Major branches of coronary arteries

    Left coronary artery branches into the anterior interventricular and circumflex arteries; right coronary artery branches into the marginal and posterior interventricular arteries.

  • Structural and functional properties of cardiac muscle

    Cardiac muscle is striated, involuntary, branched, with intercalated discs for electrical coupling, allowing synchronized contraction unlike skeletal muscle.

  • Excitation-contraction coupling in cardiac muscle

    Action potential triggers Ca2+ influx, which induces Ca2+ release from the sarcoplasmic reticulum, leading to muscle contraction.

  • Action potentials in pacemaker vs contractile cells

    Pacemaker cells have spontaneous depolarization and no stable resting potential; contractile cells have a stable resting potential and a plateau phase for sustained contraction.

  • Components of the heart conduction system

    Includes the sinoatrial (SA) node, atrioventricular (AV) node, bundle of His, bundle branches, and Purkinje fibers.

  • Conduction pathway of the heart

    Impulse starts at SA node → AV node → bundle of His → bundle branches → Purkinje fibers → ventricular contraction.

  • Normal electrocardiogram (ECG) waves and intervals

    P wave: atrial depolarization; QRS complex: ventricular depolarization; T wave: ventricular repolarization; intervals represent conduction times.

  • Abnormalities detected on ECG

    Includes arrhythmias, heart block, ischemia, and myocardial infarction indicated by changes in wave shape, timing, or intervals.

  • Timing and events of the cardiac cycle

    Includes atrial systole, ventricular systole, and diastole phases coordinating contraction and relaxation for blood flow.

  • Normal heart sounds and murmurs

    Normal sounds: lub-dub from valve closures; murmurs are abnormal sounds from turbulent blood flow due to valve issues.

  • Factors regulating stroke volume

    Include preload (venous return), contractility (strength of contraction), and afterload (resistance to ejection).

  • Factors regulating heart rate

    Include autonomic nervous system input, hormones, body temperature, and fitness level.

  • Role of autonomic nervous system in cardiac output

    Sympathetic stimulation increases heart rate and contractility; parasympathetic stimulation decreases heart rate, modulating cardiac output.