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10 Cards in this Set
- Front
- Back
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Principle Functions of the Cardiovascular System |
The cardiovascular system delivers oxygen and nutrients to the body tissues and carries away wastes such as carbon dioxide via blood. |
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Describe the location and orientation of the heart |
Snugly enclosed within the inferior mediastinum. The medial section of the thoracic cavity, the heart is flanked on each side by the lungs its pointed apex is directed toward the left hip and rests in the diaphragm, approx level with the 5th intercostal space. It's broad posterosuperior aspect or base from which the great vessels of the body emerge, points towards the right shoulder and lies beneath the 2nd rib |
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Component layers of the heart wall |
The outer epicardium - visceral layer of serous pericardium
The Myocardium- consists of thick bundles of cardiac muscle twisted and whirled into ringlike arrangements. These layers actually contract.
The Endocardium - thin, glistening sheet of endothelium that lines the heart chambers. It is continuous with the linings of the blood vessels leaving and entering the heart. |
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Principle functions of the layers of the heart wall |
Epicardium - thin layer of connective tissue and fat serving as an additional layer of protection for the heart. Myocardium- the muscle tissue of the heart, composed of cardiac muscle cells called cardiomyocytes that receive nervous stimulation from the SA and AV nodes Endocardium- endothelial cells that provides a smooth, non adherent surface for blood collection and pumping and may help regulate contractility |
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External heart functions |
. Primary function is to move blood throughout the body
. Delivering oxygen and nutrients: blood carries oxygen and nutrients to cells
. Removing waste: removes CO2 and other waste products so other organs can dispose of them
. Regulating heart Rate: the heart controls its rhythm and speed
. Maintaining Blood Pressure: it works in conjunction with the nerves and endocrine System to regulate blood pressure |
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Chambers of the heart and great vessels |
Chambers . Right and Left Atria (top chambers) . Right and Left Ventricles (bottom chambers) Great Vessels . Superior Vena Cava . Inferior Vena Cava . Left and Right Pulmonary arteries . Left and Right Pulmonary veins . Aorta |
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Components of cardiac cycle and movement of blood during each element |
FOUR stages
1. Atrial Diastole During this phase with Atria are relaxed. Blood flows passively into the right atrium from the superior and inferior Vena Cava and the coronary sinus.
2. Atrial systole The Atria contract, pushing any remaining blood into the Ventricles. The mitral and tricuspid valve open, allowing blood to flow from the Atria to the ventricles
3. Ventricular diastole The Ventricles are relaxed during early parts of this phase. In the first third of diastolic, rapid flow occurs as blood fills the ventricles. In the middle third, passive inflow continues. In the last third, atrial contraction contributes to ventricular filling before the next systole.
4. Ventricular Systole The ventricles contract forcefully . Initially all valves are closed. The semilunar valves (aortic and Pulmonary valves) then open, allowing blood to be ejected from the ventricles. Ventricles empty, reducing their volume (end- systolic volume) |
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Functions of Pulmonary and Systemic Circuits |
1. Capillary beds of lungs where gas exchange occurs 2. Oxygen rich blood travels down the Pulmonary veins 3. Through the left atrium, into the left ventricle 4. Out the aorta 5. Circulates the body and in the capillary beds of all body tissues where gas exchange occurs, O2 out and toxins and waste in. 6. The oxygen pole blood which is rich of cO2 then travels up the Vena Cava 7. The deoxygenated blood then enters the right atrium 8. Travels into the right ventricle 9. The deoxygenated blood then travels through the Pulmonary arteries back into the lungs for gas exchange |
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Functions of the heart valves |
. Mitral Valve - closes off the left atrium allowing oxygenated blood from the lungs to flow through the left ventricle. . Aortic Valve - final valve that oxygen rich blood passes through before exiting the heart and coursing through the rest of the body. Valve prevents blood from flowing back to left ventricle. . Valve prevents blood from flowing back to left ventricle. . Tricuspid Valve - blood flows through this valve leaving the right atrium and flowing into right ventricle. . Pulmonic Valve - deoxygenated blood flows through the pulmonic valve. It opens and closes to the right ventricles to allow blood flow to the lungs. |
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Valve state during cardiac cycle |
1. Atrial Diastole The Atria are in a state of relaxation. The tricuspid and mitral valves are open, allowing passive filling of ventricles with blood from veins.
2. Atrial systole The Atria contract, pushing additional blood into ventricles approx 30% ventricular filling occurs due to atrial contraction. During atrial systole the AV valve remains open
3. Ventricular diastole Both Pulmonary and aortic semilunar valves are closed during ventricular diastole
4. Ventricular systole All valves closed during the isovolumetric contraction phase. Then, the pulmonary and aortic valves open, allowing blood to be ejected from the ventricles into the arteries. |
