 Pulmonary circulation – the right side of the heart receives blood from the body and pumps it to the lungs for oxygenation  Systemic circulation – left side of the heart pumps blood through the body  Generates blood pressure  Ensures blood flow is one way only  Regulates blood supply

 Size of a closed fist, approximately 250 – 300g  Located in the mediastinum  Apex – rounded, blunt point of the heart  Base - the larger flat part

 Double layered sac that encloses the heart  Outer layer is the fibrous pericardium ◦ Prevents over distension of the heart ◦ Anchors the heart in place  Inner layer is the serous pericardium ◦ Parietal pericardium – lines the fibrous pericardium ◦ Visceral pericardium – lines the heart surface  Pericardial cavity – the space between the visceral and parietal pericardium is filled with a thin layer of serous fluid: pericardial fluid

Three Layers of Tissue 1. Epicardium (also the visceral pericardium) 2. Myocardium – thick middle layer ◦ Responsible for the heart’s ability to contract ◦ Composed of cardiac cells 3. Endocardium – inner surface of the heart chambers ◦ Simple squamous epithelium

 Four chambers: two atria, two ventricles  Veins carry blood to the heart while arteries carry blood away  Superior vena cava and inferior vena cava carry blood from the body to the right atrium  Pulmonary veins carry blood from lungs to the heart  Two major arteries: aorta and pulmonary trunk both exit the heart  Right and left coronary arteries feed the heart muscle itself

 Right atrium gets blood from body  Left atrium gets blood from lungs  Atria are separated by the interatrial septum  Atria open into the ventricles through atrioventricular valves ◦ Right ventricle opens into the pulmonary trunk ◦ Left ventricle opens into the aorta

 Atrioventricular (AV) Valves: ◦ Between right atrium and ventricle has three cusps = tricuspid valve ◦ Between left atrium and ventricle has two cusps = bicuspid (mitral) valve ◦ AV valves have cords attached to papillary muscles that prevent backflow of blood  Semilunar valves – crescent shaped ◦ Aortic semilunar valves ◦ Pulmonary semilunar valve

 Arteries – push oxygenated blood away from the heart to the body  Veins – bring deoxygenated blood back to the heart  Superior and Inferior Vena Cava – bring deoxygenated blood from the body  Pulmonary Artery – the only artery that carries deoxygenated blood, sends blood from heart to lungs  Pulmonary Vein – the only vein that carries oxygenated blood, it brings blood back to heart from lungs  Aorta – major artery that sends oxygenated blood to body

 Deox blood from the body from the Superior and Inferior Vena Cava dumps into the right atrium  Passes through tricuspid valve into right ventricle  Passes through Pulmonary semilunar valve to the pulmonary trunk to the pulmonary arteries  Deox blood passes by lungs to become oxygenated  Oxy blood passes through pulmonary veins to left atrium  Passes through bicuspid valve to left ventricle  Passes through Aortic semilunar valve to aorta  Passes through to coronary arteries and to the rest of the body

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 System consists of two nodes and a conducting bundle ◦ Nodes are located within the walls of the right atrium ◦ Sinoatrial (SA) node is medial to the superior vena cava ◦ Atrioventricular (AV) node is medial to the right AV valve ◦ Atrioventricular (AV) bundle is located next to the AV node  Purkinje fibers: spreads heart beat signal through the muscle fibers

 SA Node is the “pacemaker” of the heart ◦ Starts the signal pathway  Signal passes to the AV node  From AV node to AV bundle  From AV bundle to right and left bundle branches  From bundle branches to Purkinje fibers

 Systole – contraction, no blood can enter  Diastole – relaxation, blood fills 1. Atrial systole – ventricles fill with blood, AV valves open, SL valves close 2. Ventricular systole – atria fill with blood, AV valves close, SL valves open to move blood into arteries  Alternating patterns of systole and diastole create the lub dub heart sounds

 Systolic – the top, higher number ◦ Measures the pressure in the arteries when the heart contracts  Diastolic – the bottom, lower number ◦ Measures the pressure in the arteries when the heart rests Blood Pressure Category Systolic mm Hg (upper #) Diastolic mm Hg (lower #) Normal less than 120 and less than 80 Prehypertension120 – 139or80 – 89 High Blood Pressure (Hypertension) Stage – 159or90 – 99 High Blood Pressure (Hypertension) Stage or higher or 100 or higher Hypertensive Crisis Hypertensive Crisis (Emergency care needed) Higher than 180 or Higher than 110

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 Myocardial infarction: blood stops flowing to a part of the heart  This can lead to a major injury in the heart muscle itself  Symptoms: D1O4 D1O4

 Congestive Heart Failure is when the heart’s pumping power is weakened ◦ Blood moves through the body slower (failure) ◦ The heart has to work harder so blood pressure increases ◦ Fluids build up in tissues causing swelling and “congestion”  zYxU zYxU

 Essentially, this disease is caused by abnormalities in the heart’s anatomy caused at birth  XLl4c XLl4c  yBU yBU

 Typically caused by bad valves, a murmur is when the blood leaks backward into the atria  lOE lOE