Ch 21: Cardiovascular System – The Heart – Pulmonary & Systemic Circuits Location of Heart within Thoracic Cavity Pericardium – Covering Structure of Heart Wall

Ch 21: Cardiovascular System - The Heart - Pulmonary & Systemic Circuits Location of Heart within Thoracic Cavity Pericardium - Covering Structure of Heart Wall www.phwiki.com

Ch 21: Cardiovascular System – The Heart – Pulmonary & Systemic Circuits Location of Heart within Thoracic Cavity Pericardium – Covering Structure of Heart Wall

Bullard, Yvette, On-Air Personality has reference to this Academic Journal, PHwiki organized this Journal Ch 21: Cardiovascular System – The Heart – Give a detailed description of the superficial in addition to internal anatomy of the heart, including the pericardium, the myocardium, in addition to the cardiac muscle. Explain the functioning of the valves of the heart in addition to how they relate to the heart sounds. Discuss the conductive pathway of the heart, in addition to relate that to clinical uses of the ECG. Goals Pulmonary & Systemic Circuits artery vein capillaries Location of Heart within Thoracic Cavity Inside thoracic cavity In center of chest deep to sternum, apex tipped toward the left; base superior Inside mediastinum In pericardial space

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Pericardium – Covering 1. Fibrous pericardium – tough, collagenous 2. Serous parietal pericardium (lines fibrous pericardium) 3. Pericardial space with 10-20 ml of pericardial fluid 4. Serous visceral pericardium adheres to the heart surface (also known as epicardium) Structure of Heart Wall Epicardium = visceral Pericardium (serosa) Myocardium: muscle tissue + c.t. + blood vessels + Endocardium: simple squamous epithelium continuous with endothelia of blood vessels Cardiac Muscle Striated, aerobic, interwoven, autorhythmic Intercalated discs – gap junctions, strong desmosomes Functional syncytium Fig 21.3

Fibrous Skeleton Internal c.t. network with lots of collagen in addition to elastic fibers Encircles bases of great vessels Encircles bases of valves functions: Isolate atria from ventricles elctrically Rein as long as ce myocardium itself Surface Anatomy of Heart Auricle of atria (exp in addition to able) Coronary sulcus (between atria & ventricles) Ant. & post. interventricular sulcus Base (3rd costal cartilage) vs. apex (5th intercostal space) Vessels entering & leaving the heart Fig 21.5 Sectional (Internal) Heart Anatomy Atria & ventricles Interatrial & interventricular septae Valves (fibrous tissue) Pectinate muscles (auricles & ant. atria) Trabeculae carneae (ventricles) Chordae tendinae & papillary muscles Fig 21.6

Left vs. Right Ventricle Left: high pressure pump – Right: low pressure pump right chamber is thinner walled than left Ventricles separated by interventricular septum Structure in addition to Function of Valves = Mitral valve 4 sets of valves Prevent backflow of blood Close passively under blood pressure Heart sounds produced by valve closure picture taken from R ventricle, looking toward R atrium (see fig 21.6) Support as long as AV valves: valves are restrained by chordae tendinae which are in turn attached to papillary muscles (prevention of backflow!)

Mitral Valve Prolapse Most common cardiac variation (5-10% of population) Mitral valve cusps do not close properly Regurgitation during left ventricular systole Not life threatening; may be lifestyle threatening How can you diagnose Blood flow pattern through the heart Blood enters right atrium Passes tricuspid valve into right ventricle Leaves by passing pulmonary semilunar valves into pulmonary trunk in addition to to the lungs to be oxygenated Returns from the lung by way of pulmonary veins into the left atrium From left atrium past bicuspid valve into left ventricle Leaves left ventricle past aortic semilunar valves into aorta Distributed to rest of the body Actual physical contraction pattern of the myocardium as determined by the conduction. Contraction is systole Relaxation is diastole The two atria are in systole in addition to diastole together as are the two ventricles. Cardiac Cycle

Auscultation of Heart Sounds: 1st HS: at beginning of ventricular contraction, due to 2nd HS: at beginning of ventricular diastole, due to Coronary Circulation Coronary arteries: first branches off the ascending aorta. coronary veins coronary sinus right atrium (inferior to opening of inferior vena cava) posterior view

Coronary Artery Disease (CAD) PET scan the brighter the color the greater the blood flow through tissue due to consequences Myocardial Infarction (MI) ~ 1.3 Mio MIs / year in US Most commonly due to severe CAD (coronary thrombosis) Ischemic tissue degenerates nonfunctional area = infarct Predisposing factors Conducting System of the Heart Specialized muscle cells (autorhythmic cells) conduct APs to time in addition to synchronize the action of the chambers SA node -pacemaker, spontaneously depolarizes most rapidly in addition to initiate heart beat, positioned on back wall of right atrium , transmits action potential to AV node – (where the four chambers meet). AV bundle (bundle of His) transmits down top of interventricular septum where it divides into two Bundle branches, one of which supplies each ventricle where they branch into Purkinje fibers reflect up external walls of ventricles in addition to stimulate contraction of cardiac muscle cells as a unit. Purkinje fibers extend into papillary muscles as well

Bullard, Yvette WHLW-FM On-Air Personality www.phwiki.com

Bullard, Yvette On-Air Personality

Bullard, Yvette is from United States and they belong to WHLW-FM and they are from  Montgomery, United States got related to this Particular Journal. and Bullard, Yvette deal with the subjects like Religious Programming

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