The Cardiovascular System {The Heart}

1. The Cardiovascular System{The Heart} Chapter 13

2. Cardiovascular System a/k/a Circulatory System • Heart • Pumps blood • Blood • Fluid of system • Blood vessels • Pathway of tubules for blood • Veins (venules): capillaries  heart • Vena cava = largest veins • Arteries (arterioles): heart  capillaries • Aorta = largest artery

3. Terminology • Cardiology: study of the structure, function, & diseases of the heart • Electrocardiogram (ECG): recording of electrical changes that accompany heart beat • Cardiac cycle: one heart beat • Systole: contraction of heart muscle • Diastole: relaxation of heart muscle • Stroke volume: the amount of blood pumped out per beat • Septum: divider

4. About the heart… • Located in the mediastinum between lungs • 2/3 to the left of midline • Approx. the size of a fist • Apex (tip) points downward • Heart muscle = myocardium

5. Tissues of the heart • Membranes (serous fluid in between layers) • Parietal pericardium: makes up a tough, fibrous cavity that the heart sits in • Visceral pericardium: covers surface of the heart **Inflammation of the pericardial membranes = pericarditis • Muscle • Epicardium: covers the exterior surface of the heart • Myocardium: bulk of heart muscle • Endocardium: lines the interior cavities of the heart

6. Cardiopulmonary Resuscitation (CPR) • Rhythmic compression of the heart • Coupled with artificial respiration it can be life saving • Works because the heart is sandwiched between 2 firm surfaces • Anteriorly, the sternum • Posteriorly, the body of the vertebrae

7. Conditions/Disorders/Diseases • Angina pectoris: chest pain (usually precursor to heart attack) • Myocardial infarction: heart attack; caused by insufficient blood flow to myocardium; therefore tissue dies • Heart murmur: valve disorder; causes backflow of blood • Palpitation: irregular heart beat • Phlebitis: Inflammation of a vein • Hypertension: high blood pressure • Cardiovascular Disease

8. 5 types of circulation • Systemic: blood pumping to body (system) • Pulmonary: blood pumping to the lungs • Coronary: blood pumping to the heart itself • Fetal: circulation of blood to and from the placenta • Hepatic: blood going through liver to be filtered and detoxified

9. Electricity of the Heart • Sinoatrial (SA) node: the heart’s natural pacemaker; initiates action potentials; located in atrial wall • Atrioventricular (AV) node: the heart’s “back up” pacemaker • Bundle of His & Purkinje fibers carry impulse throughout heart

10. When SA node initiates… • 1st: atria contract simultaneously while ventricles are relaxing • 2nd: atria relax while ventricles simultaneously contract **This simultaneous contraction and relaxation results in a lubb-dupp sound

11. The lubb-dupp of your heart… • Results from closing of heart valves • Lubb = quiet; systole of atria; diastole of ventricles (AV valves closing) • Dupp= loud; systole of ventricles; diastole of atria (semilunar valves closing) • 1 heart beat (cardiac cycle) takes about 0.8 seconds • Average resting heart rate = 75 bpm (beats per minute) • Average stroke volume = 70mL

12. Chambers Upper Right atrium Left atrium Lower Right ventricle Left ventricle Vessels Pulmonary Pulmonary artery Right & left branches Pulmonary veins 2 right & 2 left branches Systemic Superior vena cava Inferior vena cava aorta Components of heart

13. Valves of the heart • Function: to prevent backflow of blood • Held in place by papillary muscle (in base of chamber) & chordae tendineae • Lessens chance of oxygenated & deoxygenated blood mixing • Right AV valve (tricuspid): b/w right atrium & ventricle • Left AV valve (bicuspid/mitral): b/w left atrium & ventricle • Pulmonary semilunar valve: b/w right ventricle & pulmonary artery • Aortic semilunar valve: b/w left ventricle & aorta

14. Blood Flow Through Heart{Pulmonary Circulation} • Superior vena cava (from upper body) & inferior vena cava (from lower body) carry deoxygenated blood  right atrium • When right atrium fills, it contracts and forces blood through the right AV valve (tricuspid)  right ventricle • When right ventricle fills, it contracts and forces blood through the pulmonary semilunar valve  pulmonary artery (trunk) • The trunk of the pulmonary artery divides into right and left pulmonary branches  right and left lungs • In lungs: oxygen and carbon dioxide are exchanged

15. Blood Flow Through Heart{Systemic Circulation} • Pulmonary veins carry oxygenated blood  left atrium • When the left atrium fills, it contracts and forces blood through the left AV valve (bicuspid, mitral)  left ventricle • When the left ventricle fills, it contracts and forces blood through the aortic semilunar valve  aorta (ascending, arch, & descending) • Aorta  entire body

16. Blood Flow Through Heart{Coronary Circulation} • Aorta • Ascending (1st inch) • Coronary vessels branch off here • Go back to myocardium • Arch (curve) • 3 branches: services left arm, head & neck, and right arm • Descending (remainder) • Thoracic aorta • Abdominal aorta  iliac arteries in legs

17. Overview Superior & inferior vena cava  right atrium  right AV valve (tricuspid)  right ventricle  pulmonary semilunar valve  pulmonary artery (& branches)  lungs (drop off CO2, pick up O2)  pulmonary veins  left atrium  left AV valve (bicuspid, mitral)  left ventricle  aortic semilunar valve  aorta  body (drop off O2, pick up CO2)

18. The Double Pump • Although we describe the flow of blood as linear, it is truly a double pump • Both atria contract together • Both ventricles contract together • Myocardium in the right side of the heart is thinner as it is pumping to the nearby lungs • Myocardium in the left side of the heart is thicker as it is pumping all over the body

19. Exceptions to the rule… • Most of the time • Veins carry deoxygenated blood (dark reddish purple blood) • Arteries carry oxygenated blood (bright red blood) • However, • Pulmonary arteries & umbilical arteries carry deO2 blood • Pulmonary veins & umbilical veins carry O2 blood

20. You must know… • The flow of blood through the heart • 4 chambers • 5 vessels • 4 valves (all names)