1. 13 - 1 Ch. 13 – Cardiovascular/Circulatory System I.Introduction A.The blood vessels form a closed tube that carry 7,000 liters of blood away from the heart, to the cells, and back again B.Vessels – 5 types 1.the heart pumps blood thru arteries, then to smaller arterioles, to tiny capillaries  Arteries are thick vessels adapted for carrying high-pressure blood away from the heart

2. 13 - 2 2.capillaries are the sites of nutrient, electrolyte, gas, & waste exchange 3.capillaries return blood to small venules, then onto larger veins  Veins are thinner than arteries & return blood to the heart Pg. 338

3. 13 - 3 This is what happens when blood is drawn from a deeper artery, rather than a superficial vein

4. 13 - 4 C.Two Circuits 1.Pulmonary Circuit – sends deoxygenated blood to lungs (to pick up O 2 and drop off CO 2 ) 2.Systemic Circuit – sends oxygenated blood and nutrients to all body cells and removes wastes Pg. 324

5. 13 - 5 II. Structure of the Heart A.The heart is a hollow, muscular pump within the thoracic cavity B.Coverings of the Heart 1.Pericardial sac encloses the heart a.fibrous pericardium - outer, tough connective tissue b.parietal pericardium - lines fibrous pericardium 2.visceral pericardium (epicardium) – surrounds the heart 3.pericardial cavity – fluid filled space b/t sac & v.p. to reduce friction Pg. 325

6. 13 - 6 C.Wall of the Heart – 3 layers 1.Epicardium - outermost layer made of connective tissue; houses capillaries, coronary arteries, & cardiac veins 2.Myocardium – thickest, middle layer that consists of cardiac muscle 3.Endocardium - inner layer; lines inside of heart Pg. 326

7. 13 - 7 D.Heart Chambers 1.The heart has 4 chambers – 2 atria & 2 ventricles a.Atria receive blood returning to the heart and have thin walls & flap-like auricles projecting from their exterior b.The thick-walled ventricles pump blood to the body 2.Each also has an atrioventricular (A-V) valve to ensure one way flow of blood 3.A septum divides the atrium & ventricle on each side Pg. 331

8. Deoxygenated Blood  Superior & Inferior vena cava  Right atrium  Tricuspid valve  Right ventricle  Pulmonary Valve  Pulmonary trunk  2 Pulmonary arteries  Capillaries of LUNGS  13 - 8 E.Path of Blood through the Heart Oxygenated Blood  4 Pulmonary veins  Left atrium  Bicuspid/Mitral valve  Left ventricle  Aortic valve  Aorta  Cells of the Body

9. 13 - 9 1.A-V valves open & close using chordae tendinae (heart strings), attached to papillary muscles  Valves prevent backflow of blood into atria 2.Pulmonary & Aortic valves are also known as Semi-Lunar valves, due to their crescent shapes Pg. 328 Pg. 329 http://goo.gl/ugRY04http://goo.gl/ugRY04 (Blood Flow) Circulatory System rap!

10. 13 - 10 F.Blood Supply to the Heart Muscle 1.Coronary arteries feed the heart muscle (myocardium) with O 2, from the aorta 2.Cardiac veins drain CO 2 -ridden blood from the myocardium & carry it to the superior and inferior vena cavae Pg. 331

11. 13 - 11 III. Heart Actions A.Blood pressure is the force of blood against the inner walls of arteries (120/60)  systolic pressure over diastolic pressure B.The cardiac cycle consists of: 1.Atria beating in unison (atrial systole) 2.Contraction of both ventricles (ventricular systole = systolic pressure) 3.The entire heart relaxes for a moment (diastole = diastolic pressure) C.Pulse - ventricle contraction felt in arteries

12. 13 - 12 D.Heart Sounds – due to vibrations in heart tissues as blood rapidly changes velocity within the heart 1.Heart sounds can be described as "lubb-dupp" sounds or“Korotkoff” sounds 2.“lubb” occurs as ventricles contract (Tricuspid & Bicuspid valves close) 3.“dupp” occurs as ventricles relax (Pulmonary & Aortic valves close) LISTEN: http://goo.gl/ugRY04 http://goo.gl/bv7gDi

13. 13 - 13 IV.Cardiac Conduction System A.A few clumps of cardiac muscle tissue initiate & distribute impulses through the myocardium, from 1 intercalated disk of a cardiac muscle cell to the next disk B.Sinoatrial (S-A) Node – a pacemaker 1.a small, elongated mass of tissue beneath the epicardium 2.located in the R-atrium, near the opening of the superior vena cavae 3.w/o outside agents, the nodal cells spread impulses to cause the heart to contract

14. 13 - 14 C.Path of Stimulation 1.S-A node sends impulse & the atria contract simultaneously, sending blood into the ventricles 2.The impulse then travels to the atrioventricular (A- V) node & onto the A-V bundle at the top of the septum 3.About halfway down the septum, the A-V bundle branches into Purkinje fibers 4.Purkinje fibers spread to papillary muscles that form whorls in the walls of the ventricles Pg. 334

15. 13 - 15 5.When impulses reach Purkinje fibers, the ventricles contract with a twisting motion, forcing blood into the aorta and pulmonary trunk LOOK & LISTEN: Cardiac Conduction & Sounds http://goo.gl/ugRY04 http://goo.gl/ugRY04 Arrhythmias http://goo.gl/rsLwlJhttp://goo.gl/rsLwlJ Pg. 334

16. 13 - 16 D.Electrocardiogram (ECG or EKG) 1.a recording of the electrical changes that occur in the myocardium during a cardiac cycle 2.body fluids can conduct electrical currents, so such changes can be detected on the surface of the body Pg. 335

17. 13 - 17 3.Patterns  P wave: depolarization of atrial fibers that lead to atrial contraction  QRS complex: when rapid depolarization in ventricular fibers comes to an end (at the same time, atrial fibers repolarize, but are immeasurable)  T wave: repolarization of ventricular muscle fibers Pg. 335 Time b/t intervals can signal heart problems