MedSurg Test 1.docx - Cardiovascular Function Overview of Anatomy and Physiology 3 layers of the heart o Endocardium Inner layer o Myocardium Middle

MedSurg Test 1.docx - Cardiovascular Function Overview of...

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Cardiovascular Function: Overview of Anatomy and Physiology: 3 layers of the heart o Endocardium Inner layer o Myocardium Middle layer Muscle of the heart Responsible for the pumping action o Epicardium Exterior layer 4 chambers of the heart o Right atria and ventricle o Left atria and ventricle o During the relaxation phase ( diastole ) all four chambers relax simultaneously , which allows for the ventricles to fill in preparation for contraction Diastole is commonly referred to as ventricular filling o During systole , the heart contracts Atrial and ventricular systole are NOT simultaneous Atrial systole occurs first , just at the end of ventricular diastole, followed by ventricular systole o The thickness of the atria and ventricle walls are due to the workload required by each chamber The ventricular walls are much thicker than the atrial walls Heart Valves o There are four valves in the heart that permit blood to flow in only one direction; they open and close in response to the movement of blood and pressure changes within the chambers o Atrioventricular Valves: Tricuspid valve: separates the right atrium from the right ventricle Bicuspid/Mitral valve: separates the left atrium from the left ventricle During diastole , the tricuspid and bicuspid valves are open , allowing the blood in the atria to flow freely into the relaxed ventricles As ventricular systole begins, the ventricles contract and blood flows upward into the cusps of the tricuspid and bicuspid valves, causing them to close o Semilunar Valves: Pulmonic valve: between the right ventricle and the pulmonary artery Aortic valve: between the left ventricle and the aorta During diastole, the semilunar valves are closed Coronary Circulation: o The right side of the heart distributes venous blood ( deoxygenated blood ) to the lungs via the pulmonary artery o The left side of the heart distributes oxygenated blood to the remainder of the body via the aorta o The actions of the right side and left side of the heart are working at the same time. As the right atria is filling, so is the left atria, as the right ventricle is filling, so is the left o Watch the video below
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Cardiac Conduction System: o The cardiac conduction system generates and transmits electrical impulses that stimulate contraction of the myocardium o SA (sinoatrial) Node AV (atrioventricular) Node Bundle of His Right & Left Bundle Branches Purkinje Fibers o The SA node is the pacemaker of the heart Cardiac Hemodynamics: o Cardiac Cycle: Refers to the events that occur in the heart from the beginning of one heartbeat to the next Each cardiac cycle has three major sequential events: Diastole All four chambers and relaxed ; causing pressure in the chambers to be at its lowest this facilitates ventricular filling Atrial systole Atria contract Ventricular systole Ventricles contract
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o Cardiac Output: Refers to the
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