5 .Health assessment 21..docx - Chapter 21 Assessing Heart and Neck Vessels Structure and Function:Heart\u2022 Hollow,muscular organ \u2014 Located in

5 .Health assessment 21..docx - Chapter 21 Assessing Heart...

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Chapter 21 Assessing Heart and Neck Vessels Structure 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, endocardium Heart Chambers, Valves, and Direction of Circulatory Flow Question: 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 fibers Electrocardiogram
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 considerations Collecting Subjective Data History of present health concern: chest pain, palpitations Past health history Family history

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