Human Heart and its function

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Human Heart and its function

  1. 1. HUMA N CI RCULA T O RY
  2. 2. •Is a muscle about the size of your fist •Weighs approximately one pound •Is located behind and slightly to the left of the breastbone •Pumps about 4.7 liters of blood every minute
  3. 3. Heart size - about 14 cm long by 9 cm wide Cardiovascular system
  4. 4. 1) pericardium = double- layer serous membrane 2) endocardium - squamous epithelial inner lining of the heart coverings
  5. 5. c. chambers 1) atria - receive blood from the vessels a) pectinate muscles - ridges of muscle in anterior wall
  6. 6. 2) auricles - small expandable attachments to the atria a) pectinate muscles (Latin pecten = comb)
  7. 7. 4) ventricles - pump blood to body by contraction of myocardium. a) walls are thicker than atria, left side thickest ventricles - pump blood to body by contraction of myocardium. a) walls are thicker than atria, left side thickest
  8. 8. interventricular septum - parallels a groove in the outer surface of the heart (the interventricular sulcus). valves - allow only one direction of flow 1) atrioventricular (AV) valves a) tricuspid - 3 folded valve between right A and V b) biscuspid - mitral valve - 2 folded on left side c) made of dense connective tissue
  9. 9. Semilunar valves - between ventricle and the first major artery. a) Right ventricle and pulmonary trunk - pulmonary b) Left ventricle and aorta - aortic valve chordae tendineae = attach cusps to papillary muscles. c) 3 half-moon shaped cusps
  10. 10. a) Thinner walls and smaller lumen. 3) Capillaries a) Single layer of epithelium only b) lumen diameter .01 mm 2. Blood Vessels a. Structure 1) Arteries and veins 2 1) s . Blood Vessels a. Structure 2. Blood Vessels 1) Arteries and veins c) form vast branching networks a) Arteries have thicker smooth muscle layer while veins have larger lumen and also have valves. 2) Arteriloe and venules
  11. 11. a. Cardiac cycle - the contraction of both atria and then both ventricles. Cardiac cycle - the contraction of both atria and then both ventricles. 1) systole = state of contraction (blood forced out) 2) diastole = state of relaxation (blood drawn in) 3) both ventricles at the relax or contract at the same time 4) likewise atria are simultaneous
  12. 12. Heart sounds - results from valves shutting lub = AV valves dup = Semilunar valves

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