NUR 305 test 3 A

NUR 305 test 3 A - 1 Notes for Test 3 A Chapter 22 Blood...

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Unformatted text preview: 1 Notes for Test 3 A Chapter 22 Blood flow through the heart o Right Atrium o Tricuspid valve o Right ventricle o Pulmonary arteries o Lung o Pulmonary Veins o Left atrium o Mitral valve o Left ventricle o Aorta o System Structures on the right side of the heart, or right heart, pump blood through the lungs. This system is called pulmonary circulation . The right ventricle pumps blood to the lungs to refuel (rids itself of carbon dioxide and pick up oxygen). The left side of the heart, or left heart, sends blood throughout the systemic circulation , which supplies all the body except the lungs (oxygenated blood that gets pumped out to the body). o The output of one becomes the input of the other (pulmonary and systemic). 2 o Arteries carry blood from the heart to all parts of the body, where they branch into increasingly smaller vessels and ultimately become a fine meshwork of capillaries. Capillaries allow the closest contact and exchange between the blood and interstitial space, or interstitium, the environment in which the cells live. Veins channel blood flow from capillaries in all parts of the body back to the heart. Mediastinum- is where the heart lies diagonally, an area above the diaphragm and between the lungs (the heart weights less than a pound and is the size of a fist). The heart wall o Pericardium (outer layer) A double-walled membranous sac that encloses the heart and (1) prevents displacement of the heart during gravitational acceleration or deceleration, (2) serves as a physical barrier that protects the heart against infection and inflammation from the lungs and pleural space, and (3) contains pain receptors and mechanoreceptors to elicit reflex changes in blood pressure and heart rate. Two layers: parietal and visceral which are separated by the pericardial cavity. o Myocardium (middle and thickest layer) Composed of cardiac muscle and is anchored to the hearts fibrous skeleton. The thickness of the myocardium varies tremendously in the various heart chambers and is related to the amount of resistance the heart muscle must overcome to pump blood from that chamber. o Endocardium (inner layer) Comprises connective tissue and squamous cells. The lining is continuous with the endothelium that lines all the arteries, veins, and capillaries of the body (closed circulatory system). 3 The four chambers of the heart are left atrium, left ventricle, right atrium, and right ventricle. o The atrium is smaller and the ventricle has thicker walls. Valves of the heart o Atrioventricular valves (AV valves b/w the atrium and ventricle). During ventricular relaxation, the two AV valves open and blood flows from the atria to the relaxed ventricles. With increasing ventricular pressure, the valves close and prevent backflow into the atria as the ventricles contract....
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NUR 305 test 3 A - 1 Notes for Test 3 A Chapter 22 Blood...

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