NURS 8022 Exam 3 Study Guide Latest.

NURS 8022 Exam 3 Study Guide Latest. STRUCTURE AND FUNCTION OF THE CV AND LYMPHATIC SYSTEMS 1. Understand the basics of cardiac muscle contraction Cross-bridge cycling -Attachment of actin to myosin at the cross bridge -Myosin head molecule undergoes a position change -Causes thin filaments to slide past thick filaments (contraction) Calcium -Is stored in the tubule system and the sarcoplasmic reticulum -Enters the myocardial cell from the interstitial fluid after electrical excitation, which increases membrane permeability to calcium -Diffuses toward the myofibrils, where it binds with troponin Excitation contraction coupling - Is the process by which an action potential triggers the cycle of events, leading to cross-bridge activity and contraction - Requires calcium - Calcium-troponin complex facilitates the contraction process Myocardial relaxation - Is vital to optimal cardiac function as is contraction - Calcium, troponin, and tropomyosin also facilitate relaxation Troponin release of calcium begins myocardial relaxation. 2. Understand cardiac cycle and what each part represents Cardiac cycle -One contraction and one relaxation -Makes up one heartbeat Diastole (D=R) -Relaxation: Ventricles fill Systole (S=C) -Contraction: Blood leaves the ventricles `Phases of the cardiac cycle Phase 1: Atrial systole or ventricular diastole Phase 2: Isovolumetric ventricular systole Phase 3: Ventricular ejection (semilunar valves open) Phase 4: Isovolumetric ventricular relaxation (aortic valve closes) NURS 8022 Exam 3 Study Guide Latest. Phase 5: Passive ventricular filling (mitral and tricuspid valves open)  Atrial contraction – deoxygenated blood travels from the atria (top) to the ventricles through the AV valves (triscupid & mitral)  Isovolumetric contraction – pressure from the outside of the heart squeezes, closes the valves  Ventricular ejection – cont pressure makes the deoxygenated blood get pumped out form the right side of heart to the pulmonary veins to the lungs to get them oxygenated  Isovolumetric relaxation – release of the blood to the lungs  Atrial filling – oxygenated blood fills the atria  Ventricular filling, AV valves open, allowing oxygenated blood to enter the heart, L side pumps it all to the body Right Heart Function Left Heart Function Pumps blood through the lungs *pulmonary circulation Pumps oxygenated blood through the systemic circulation Delivers blood to the lungs for oxygenation Delivers metabolic waste products to the lungs, kidneys, & liver Is a LOW pressure system Is a HIGH pressure system 3. Understand EKG basics, waves, and intervals Normal electrocardiogram (ECG) -Sum of all cardiac action potentials P wave: Atrial depolarization (atrial contraction) PR interval: Time from the onset of atrial activation to the onset of ventricular activation (0.12-0.20 sec) QRS complex: Sum of all ventricular depolarizations ST interval: Ventricular myocardium depolarized, represents period between depolarization and depolarization of ventricles QT interval: “Electrical systole” of the ventricles - Varies inversely with the heart rate - Approximates time of ventricular contraction HR can be determined with reciprocal of time interval between each heartbeat - R-R interval 4. Remember the basic of the sequence of blood through the pulmonary system, heart, and systemic circulation, (superior vena cava, to RA, through tricuspid valve, into RV, and so on). As well as were there is oxygenated and unoxygenated blood Unoxygenated (venous) blood from systemic circulation to right atrium (RA) via superior & inferior vena cava RA through right AV (tricuspid) valve to right ventricle (RV) RV through pulmonic semilunar valve (pulmonary valve) to pulmonary artery, to lungs for oxygenation Oxygenated blood enters the left atrium (LA) through the 4 pulmonary veins (two from the left lung and two from the right) LA through the left AV valve (mitral valve) into the left ventricle (LV) LV through the aortic semilunar valve (aortic valve) into the aorta, which delivers it to the entire body.