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Chapter 21Assessing Heart and Neck VesselsStructure and Function•Heart:—Hollow ,muscular organ–Located in mediastinum-space in Middle of thoracic cavity between the lungs–Four chambers: left atrium and ventricle, right atrium and ventricle–Two atrioventricular valves, two semilunar valves(are located at the entrance into the ventricles. There are two AV valves: the tricuspid valve and the bicuspid (mitral) valve(Two semilunar valves (Located at exit of ventricles, Pulmonic and aortic(–Three layers: epicardium, myocardium, endocardiumHeart Chambers, Valves, and Direction of Circulatory FlowQuestion: The pulmonary artery returns oxygenated blood to the left atrium—.Electrical Conduction of the Heart•Cardiac cycle•Sinoatrial (SA) node -generates impulse at rate of 60 to 100 per minute -pacemaker of heart•AV node•AV bundle (bundle of His(•Purkinje fibersElectrocardiogram
•Electrical activity of heart measured by electrocardiography (ECG(•Phases of ECG: P, Q, R, S, T•Records depolarization and repolarization-P wave: Atrial depolarization; conduction of the impulse throughout the atria.-PR interval: Time from the beginning of the atrial depolarization to the beginning of ventricular depolarization, that is, from the beginning of the P wave to the beginning of the QRS complex.-QRS complex: Ventricular depolarization (also atrial repolarization); conduction of the impulse throughout the ventricles, which then triggers contraction of the ventricles; measured from the beginning of the Q wave to the end of the S wave.-ST segment: Period between ventricular depolarization and the beginning of ventricular repolarization.-T wave: Ventricular repolarization; the ventricles return to a resting state.-QT interval: Total time for ventricular depolarization and repolarization, that is, from the beginning of the Q wave to the end of the T wave; the QT interval varies with HR.-U wave: May or may not be present; if present, it follows the T wave and represents the final phase of ventricular repolarization.Cardiac Cycle•Filling and emptying of the heart’s chamber•Two phases: diastole and systole–Diastole: relaxation of the ventricles–Systole: contraction of the ventricle
Coronary Artery Disease•Risk factors:–Overview of coronary artery disease–Risk factors–Risk-reduction teaching tips–Cultural considerationsCollecting Subjective Data•History of present health concern: chest pain, palpitations•Past health history•Family history•