Chapter 22: Introduction to the Cardiovascular System PDF

Timby’s Introductory Medical– Surgical Nursing, 13e Chapter 22: Introduction to the Cardiovascular System Copyright © 2018 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomy and Physiology #1...

Timby’s Introductory Medical– Surgical Nursing, 13e Chapter 22: Introduction to the Cardiovascular System Copyright © 2018 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomy and Physiology #1 Heart Chambers o Four chambers Atria (upper) Ventricles (lower) Septum Right side: pulmonary circulation Left side: systemic circulation Copyright © 2022 Wolters Kluwer · All Rights Reserved Anatomy and Physiology #2 Cardiac Tissue Layers o Epicardium: outer layer; fibrous and loose connective tissue Loading… o Myocardium: middle layer; muscle tissue o Endocardium: inner layer; thin, smooth layer of endothelial cells o Pericardium: saclike structure; two layers: parietal and visceral Serous fluid between layers: reduces friction Copyright © 2022 Wolters Kluwer · All Rights Reserved Anatomy and Physiology #3 Heart Valves o Ensures that blood passes through the heart in a one-way, forward direction; no regurgitation o Atrioventricular (AV) valves Separate the atria from ventricles; cusped, leaflike Tricuspid valve: right atrium and ventricle Bicuspid valve (mitral): left atrium and ventricle Chordae tendineae, papillary muscles Copyright © 2022 Wolters Kluwer · All Rights Reserved Anatomy and Physiology #4 Heart Valves—(cont.) o Semilunar valves: prevent blood from flowing back into the ventricles Loading… Pulmonic valve (pulmonary): right ventricle and pulmonary artery Aortic valve: left ventricle and aorta Function from contraction and relaxation of the ventricles Copyright © 2022 Wolters Kluwer · All Rights Reserved Question #1 The major functions of the cardiovascular system are to perform all of the following, except: A) Supply of oxygen-rich blood to tissues B) Elimination of carbon dioxide C) Transportation of nutrients D) Exchange of oxygen and carbon dioxide Copyright © 2022 Wolters Kluwer · All Rights Reserved Answer to Question #1 D) Exchange of oxygen and carbon dioxide Rationale: The exchange of oxygen and carbon dioxide between the body and the outside environment is a function of the lungs known as ventilation and is not a primary function of the heart. Copyright © 2022 Wolters Kluwer · All Rights Reserved Anatomy and Physiology #5 Arteries and Veins o Arteries: carry oxygenated blood from the heart Arterioles: dilate or constrict o Veins: return deoxygenated blood to the heart Venules: larger diameters; lower venous pressure o Capillaries: direct contact with cells Deliver oxygen and metabolic substances to cells Copyright © 2022 Wolters Kluwer · All Rights Reserved Anatomy and Physiology #6 Cardiopulmonary Circulation o Inferior and superior vena cava: deoxygenated blood into the right atrium o Pulmonary artery: delivers venous blood to the lungs o Pulmonary veins: oxygenated blood to left atrium Transportation of blood to left ventricle o Aorta: oxygenated blood from heart to all body cells and tissues Copyright © 2022 Wolters Kluwer · All Rights Reserved Anatomy and Physiology #7 Blood Supply to the Heart o Coronary arteries Coronary ostia: myocardium oxygen-rich blood o Coronary veins Carry CO2 away— inferior and superior venae cavae Copyright © 2022 Wolters Kluwer · All Rights Reserved Anatomy and Physiology #8 Cardiac Cycle o Electrical and mechanical events in atria and ventricles Loading… Diastole: filled atria contract Systole: contracted ventricles o Conduction system: sustains the electrical system of the heart Copyright © 2022 Wolters Kluwer · All Rights Reserved Conduction System of the Heart #1 Sinoartial node (SA) o Pacemaker of the heart; 60 to 100 impulses per minute Atrioventricular node (AV) Bundle of His Bundle branches Purkinje fibers o Ventricular contraction Copyright © 2022 Wolters Kluwer · All Rights Reserved Conduction System of the Heart #2 Polarization: diastole; myocardial cells at rest Depolarization: cardiac muscle contraction Repolarization: polarized alignment; another electrical impulse Refractory period: cells resist electrical stimulation o Electrocardiograph (ECG): detection of electrical activity Copyright © 2022 Wolters Kluwer · All Rights Reserved Anatomy and Physiology #9 Regulation of Heart Rate o Autonomic nervous system; sympathetic and parasympathetic nervous system Baroreceptors: pressure-sensitive nerve endings, BP compensation Chemoreceptors: sensitive to pH and CO2, alters heart rate See Box 22-1 Cardiac output: 4 to 8 L/minute; stroke volume Copyright © 2022 Wolters Kluwer · All Rights Reserved Assessment of the Cardiovascular System #1 History: past medical history and family history o Familial and genetic predisposition o Prescription and nonprescription drug use Physical Exam o General appearance: ischemia; chest pain or leg pain o Vital signs: temperature; fever; pulse rate, rhythm, and pulse volume; pulse deficit; respiratory rate; accessory muscles; blood pressure o See Nursing Guidelines 22-1 and Evidence-Based Practice 22-1 Copyright © 2022 Wolters Kluwer · All Rights Reserved Assessment of the Cardiovascular System #2 Cardiac Rhythm o Heart’s electrical, not mechanical, activity; palpate peripheral pulse or auscultate apical heart rate o Telemetry Normal Heart Sounds o S1/S2; “lub-dub”; apex of heart o Abnormal heart sounds: S3—ventricular gallop, S4—atrial gallop, murmurs and clicks, friction rub Copyright © 2022 Wolters Kluwer · All Rights Reserved Assessment of the Cardiovascular System #3 Peripheral pulses o Radial pulses o Leg pulses bilaterally o Presence/absence and strength Copyright © 2022 Wolters Kluwer · All Rights Reserved Question #2 The function of the tricuspid valve is: A) Allows blood to flow out of the left ventricle into aorta B) Allows blood to flow from right atrium into right ventricle C) Allows blood to flow out of right ventricle into the pulmonary artery D) Allows blood to flow from left atrium to left ventricle Copyright © 2022 Wolters Kluwer · All Rights Reserved Answer to Question #2 B) Allows blood to flow from right atrium into right ventricle Rationale: The function of the tricuspid valves is to prevent blood from returning to the atria when the ventricles contract. The tricuspid valve is between the right atrium and right ventricle. Copyright © 2022 Wolters Kluwer · All Rights Reserved Assessment of the Cardiovascular System #4 Skin: assess for cyanosis and pallor o Color changes to mucous membranes, lips, earlobes, skin, and nail beds; sparse hair growth; thick toe nails, varicosities Peripheral edema: pitting edema; scale +1 to +4 Weight: indicates edema; daily Jugular veins—distention; increased pressure on the right side of the heart Copyright © 2022 Wolters Kluwer · All Rights Reserved Assessment of the Cardiovascular System #5 Lung sounds: crackles, wheezes, and gurgles Sputum: frequency, amount, and appearance o Pulmonary complications, heart failure Mental status o cerebral ischemia; confusion and disorientation Copyright © 2022 Wolters Kluwer · All Rights Reserved Question #3 A nurse is examining a client with a history of cardiac disease. An assessment finding that indicates cardiac dysfunction includes which of the following? A) Presence of pedal edema B) Irregular heart rhythm C) Clubbing of fingers D) All of the above Copyright © 2022 Wolters Kluwer · All Rights Reserved Answer to Question #3 D) All of the above Rationale: Abnormal vital signs including heart rate; abnormal heart sounds; and general appearance changes including skin temperature, distended neck veins, clubbing of fingers, and presence of edema are all assessment findings associated with cardiovascular disease. Copyright © 2022 Wolters Kluwer · All Rights Reserved Diagnostic Tests #1 Laboratory Tests o Serum enzymes and isoenzymes, serum cholesterol, lipid analysis Radiography and Radionuclide Studies o Determines size and position of heart o Nuclear cardiology—myocardial damage Echocardiography o Functioning of left ventricle, tumors, congenital defects, changes in tissue layers of heart; TEE Copyright © 2022 Wolters Kluwer · All Rights Reserved Diagnostic Tests #2 Magnetic resonance imaging (MRI): cardiac anatomy, function, blood flow, metabolism, circulatory perfusion o Preparation: screen kidney function, flushed feeling, earplugs during test, anxiety o See Box 22-2 Electrocardiography: resting, exercise o Ambulatory ECG: Holter monitoring Diary of activities and associated symptoms o Exercise ECG: stress test; increase heart’s workload Copyright © 2022 Wolters Kluwer · All Rights Reserved Diagnostic Tests #3 Drug-Induced Stress Testing o Compromised blood flow, coronary artery disease; adenosine (Adenocard), dipyridamole (Persantine) Cardiac Catheterization o Preparation: medication omission, NPO, allergies identified, IV fluids, sedative o Postprocedure: pressure dressing; BP; client instructions: avoid movement, report pain and bleeding, drink large volume of fluids o See Client and Family Teaching 22-1 Copyright © 2022 Wolters Kluwer · All Rights Reserved Diagnostic Tests #4 Coronary Arteriography o Determines degree of blockage of coronary arteries o Postprocedure: assess for bleeding, infection, vascular assessments Angiocardiography: size and shape of heart chambers and great vessels; congenital abnormalities Aortography: aortic aneurysms Peripheral arteriography: occlusive arterial disease Copyright © 2022 Wolters Kluwer · All Rights Reserved