Ms. Bowman Ms. Bowman

  Composed of the heart, veins, arteries, and blood Cardiovascular System

  About the size of a fist; weighs less than one pound  Enclosed within the mediastinum (medial cavity of the thorax)  Layers  Pericardium-double-walled sac that encloses the heart  Epicardium-covering on the outside of the heart  Myocardium-cardiac mucsle  Endocardium-sheet of endothelium located deep inside the heart Heart

  Chambers  2 Atria-located superior  Receiving chambers for blood returning to the heart  Relatively small, thin walled chambers  2 Ventricles-located inferior  Discharging chambers for blood leaving the heart  When ventricles pump, blood is propelled out of the heart  Makes up the bulk of the heart Heart

  Blood flows in one direction in the heart atria ventricles arteries  Valves  4 valves that keep blood flowing in one direction  2 Atrioventricular Valves (AV)  Located at each junction of the atria and ventricles  Prevents backflow into atria from ventricles  2 Semilunar Valves (SL)  Aortic and pulmonary SL valves  Prevents backflow from the aorta and pulmonary artery into ventricles Heart

  Important structures  Superior vena cava  Inferior vena cava  Atria  Ventricles  Aorta  AV Valves  SL Valves Heart

 Blood Pathway Through the Heart

 Blood Pathway Through the Body

  Form a closed delivery system that begins and ends at the heart  Arteries-carry blood away from the heart  Veins-carry blood towards the heart  Capillaries-very small vessels that directly serve the tissues of the body; where nutrient/oxygen exchange occurs between blood and cells Blood Vessels

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