1. Biology 250:Human Anatomy Spring 2005 Cardiovascular System

2. Cardiovascular Overview Heart: pumps blood throughout the body –Involuntary striated muscle Arteries: carries blood away from the heart –Carries oxygenated blood to body Veins: carries blood to the heart –Carries de-oxygenated blood to the heart Capillaries: connect arteries, veins

3. Heart Usually the size of a fist Weighs between 250-350 grams (< 1 lb) Sits with the mediastinum –Medial cavity of the thorax Base: broad, flat –Directed toward the right shoulder Apex: pointed end of heart –Points inferiorly toward the left hip

5. Coverings of the Heart Pericardium Double-walled sac enclosing the heart Dense Connective Tissue Purposes of Pericardium: 1.Protection 2.Anchors heart to surrounding structure 3.Prevents overfilling of heart

7. Layers of Heart Wall 3 Layers of Heart Wall 1.Epicardium Superficial Layer; usually filled with fat 2.Myocardium Middle Layer; composed of cardiac muscle 3.Endocardium Deepest Layer; Squamous Epithelium

9. Heart Chambers 4 Chambers of the Heart: 2 Superior Chambers –Right Atrium, Left Atrium –Relatively thin heart wall 2 Inferior Chambers –Right Ventricle, Left Ventricle –Thick heart wall (produces strong contraction) Interatrial/ventricular septum

13. Right Atrium Superior/Right Chamber of Heart De-Oxygenated Blood From Body 3 Major Veins: 1.Superior Vena Cava –Blood from superior portion of body 2.Inferior Vena Cava –Blood from inferior portion of body 3.Coronary Sinus –Blood from the heart itself

15. Right Ventricle Inferior/Right Chamber of Heart De-Oxygenated Blood from Right Atrium Relatively thick heart wall 2 Major Arteries: 1.Left Pulmonary Artery De-oxygenated blood to left lung 2.Right Pulmonary Artery De-oxygenated blood to right lung ONLY arteries with de-oxygenated blood

17. Left Atrium Superior/Left Chamber of Heart Oxygenated Blood From Lungs 2 Major Veins: 1.Right Pulmonary Vein Oxygenated blood from right lung 2.Left Pulmonary Vein Oxygenated blood from left lung ONLY veins with oxygenated blood

19. Left Ventricle Inferior/Left Chamber of Heart Oxygenated blood from Left Atrium Thick Heart Wall Pumps blood through major artery: –Aorta: branches into all other arteries of body

21. Coronary Arteries Arteries which supply the heart Major Coronary Arteries 1.Left Coronary Artery 2.Anterior Interventricular Artery 3.Circumflex Artery 4.Right Coronary Artery 5.Marginal Artery 6.Posterior Interventricular Artery CABG

25. Heart Valves Separate the chambers of the heart Prevent back-flow of blood Atrioventricular Valves (AV) –Separate the atrium from the ventricles 1.Right AV Valve (Tricuspid Valve) 2.Left AV Valve (Bicuspid or Mitral) –Contain Chordae Tendineae

29. Heart Valves (Cont.) Semilunar Valves (SL) –Resemble half moons 1.Pulmonary Semilunar Valve –Prevents back-flow from Pulmonary Arteries into Right Ventricle 2.Aortic Semilunar Valve –Prevents back-flow from Aorta into Left Ventricle

32. Common Valve Deficiencies Incompetent Valve –“Leaky” Valve; does not close properly Valvular Stenosis –“Stiff” Valve; does not open properly “Heart Murmur”