Cardiac and Circulatory Function PDF
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Uploaded by PolishedVeena6642
CEU Universidad Cardenal Herrera
Luis D'Marco
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This document provides a lecture on cardiac and circulatory function, covering the structure and function of the heart, blood vessels, and related concepts. It details the processes of cardiac contraction, blood flow, and the roles of different components like atria and ventricles. Illustrations and diagrams complement the text.
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Cardiac and circulatory function GENERAL PATHOLOGY 3º Prof. Luis D’Marco, MD, MSc, PhD. Structure and Function of the Normal Heart and Blood Vessels The circulatory system comprises the heart, which is connected in series to the arterial and venous vascular networks. Vascul...
Cardiac and circulatory function GENERAL PATHOLOGY 3º Prof. Luis D’Marco, MD, MSc, PhD. Structure and Function of the Normal Heart and Blood Vessels The circulatory system comprises the heart, which is connected in series to the arterial and venous vascular networks. Vascular networks are arranged in parallel and connect at the level of the capillaries The heart is composed of: Two atria (low-pressure capacitance chambers) Two ventricles (high-pressure chambers) The left ventricle is thicker than the right, in order to generate the higher systemic pressures required for perfusion. Cardiac anatomy Cardiac anatomy comprises electrical and structural components. The electrical impulse that directs cardiac contraction originates in the SA node and is rapidly conducted through the atria by specialized conduction tracts. The impulses merge at the AV node, where, after a brief pause, they are rapidly conducted into the ventricles through the bundle of His, which is composed of specialized Purkinje cells. Blood moves from the atria into the ventricles through the tricuspid and mitral valves respectively, during diastole. During systole, blood from the ventricles is pumped into the pulmonary artery and aorta through the pulmonic and aortic valves, respectively Schematic representation of the systemic and pulmonary circulatory systems. The circuitry of the cardiovascular system Arrangement of blood vessels in the cardiovascular system Comparison of laminar flow to turbulent blood flow atherosclerosis clots Capacitance of veins and arteries higher volume less pressuree less volume higher pressure older = low volume and high pressure higher risk of atherosclerosis (thickness change = higher = less expenssibility) BP higher in aged people = normal difference during higher systolic pressure ; left ventricle need to pump more (more pressure ) higher diastolic pressure : no distansion of the vessels ; higher volume of blood combine angiotensine and medicine Pressure profile in the vasculature if the veins have higher pressure : blood remains = swallen and the valve collapse usualy renal problem hormonal Response of baroreceptor reflex to increased arterial pressure hyperT = anways stimulated receptors + decrease heart rate = massage of the carotid recept on the neck ; stimulation on PE decrease heart rate cranial nerve [CN] MYOCARDIAL STRUCTURE Calcium dependence of myocardial contraction 1.- Electrical depolarization of myocyte results in an influx of Ca2+ ions into the cell through channels in the T tubules. 2.- Calcium entry stimulates the release of large amounts of Ca2+ from the sarcoplasmic reticulum (SR). and NA+ 3.- Ca2+ then binds to the troponin-tropomyosin complex on the actin filaments, resulting in a conformational change that facilitates the binding interaction between actin and myosin. In the presence of ATP, the actin-myosin association is cyclically dissociated as the thick and thin filaments slide past each other, resulting in contraction. 4.- During repolarization, Ca2+ is actively pumped out of the cytosol and sequestered in the SR. in higher acidic environment = pump doesn't work Cardiac action potential and ion channels - Myocardial contraction begins when sodium channels open and positively charged sodium ions flow into the cell and cause membrane depolarization (phase 0). - During phases 1, 2, and 3, calcium ions flow into the cell through L-type calcium channels, while potassium flows out of the cell through voltage-gated potassium channels. - These three phases correspond to myocardial contraction, which corresponds to the QRS complex on the surface ECG. - The sodium-potassium adenosine triphosphatase (NKA) helps return the system to its resting state. Wiggers diagram mitral insuffisiancy : communication btw LA and LV = lower ventricular and aortic pressure Systolic and diastolic left ventricular pressure-volume curves higher systole lower diastole Normal Heart Sounds All heart sounds should be described according to their quality, intensity, and frequency. There are two primary heart sounds heard during auscultation: S1 and S2. These are high-frequency sounds caused by closure of the valves. not the opening S1 occurs with the onset of ventricular systole and is caused by closure of the mitral and tricuspid valves. The aortic and pulmonic valve closure causes S2 and begins ventricular diastole. All other heart sounds are timed based on these two sounds. Heart sounds S2 = pulmonis and aortic S1 tricuspid and mitral S2 pulmonar and aortic Heart sounds luk duk they are together need to ear during expiration luk tru duk Cardiovascular disease The term cardiovascular disease encompasses a wide array of patient problems. The heart’s circulation, myocardium, rhythm, valves, and pericardial structures may be affected, as can the arterial or venous vascular systems. Coronary artery disease Congestive heart failure Stroke Peripheral arterial disease Atrial fibrillation and hypertension Valvular heart disease Congenital heart disease Chronic Kidney disease Approach to the Patient with Possible Cardiovascular Disease (CVD) CVD patients may present with a wide range of symptoms and signs. Conversely, patients with substantial CVD may be asymptomatic. CVD is a leading cause of death worldwide; it is crucial that patients be evaluated carefully to detect early CVD. Improvements in diagnosis, therapy, and prevention have contributed to a 70% or so decline in age- adjusted CVD death rates since the 1960s. Furthermore, among people aged 65 years and older, regular visits to a primary care physician are associated with a 25 to 30% reduction in overall mortality. However, the absolute number of deaths from CVD has not declined proportionately because of the increase in the population older than 40 years as well as the aging of the population in general. CARDINAL SYMPTOMS OF CARDIOVASCULAR DISEASE Chest pain or discomfort. no need of huge pain just small disconfort could be CV disease Dyspnea, orthopnea, paroxysmal nocturnal dyspnea, wheezing. lying down difficulty to breath ; increase of pressure of capillary of the pulmon = no interchange of oxygen Palpitations, dizziness, syncope. Cough, hemoptisis. Fatigue, weakness. Pain in extremities with exertion (claudication). DIAGNOSIS AND PHYSICAL EXAMINATION General Examination of the Jugular Venous Pulsations vein syst can show the higher pressure normal patient not see the pulsation of the jugular vein Examination of Arterial Pressure and Pulse Examination of the Precordium anatomical over the heart and lower the chest position Auscultation Cardiovascular Causes of Chest Pain Noncardiac Causes of Chest Pain jugular regurgitation oedema heart disease : increase intravascular volume hepatic and renal : oncotic pressure (no proteins = flux of the liquid to the iterstitial space) loss of albumin or no production Arterial embolism causing acute ischemia and cyanosis of the leg art obstruction or veins obstruction = ischemia and trombolisis Severe finger clubbing in a patient with cyanotic congenital heart disease. congenital heart disease btw chamber of the heart ; abnormal connexion = shunt (deoxygenated blood = cyanosis) Splinter hemorrhage ( solid arrow ) and Janeway lesions ( open arrow ). These findings should stimulate a work-up for endocarditis. Eruptive xanthomas of the extensor surfaces of the lower extremities. This patient had marked hypertriglyceridemia Diagnostic Tests and Procedures in the Patient With Cardiovascular Disease Blood and urinary analysis Electrocardiography Ambulatory electrocardiographic recording Chest radiography Echocardiography Nuclear cardiology Cardiac magnetic resonance imaging Stress testing Cardiac catheterization Diagnosis Eventos adversos según albuminuria abnormal excression of proteins in the urine Gansevoort, RT and de Jong, P. J Am Soc Nephrol. 2009 Inscription of a normal electrocardiogram (ECG) NORMAL ELECTROCARDIOGRAPHIC INTERVALS Heart rate 50-100 beats per minute P wave duration