1. THE CARDIOVASCULAR SYSTEM Honors Anatomy Chapter 18

2. Heart a Pump  receives O2-rich blood from lungs  -- > pumps it to tissues  receives O2-poor blood from tissues  pumps it to lungs Left Side Right Side

3. Heart Anatomy  ~ fist size  250 – 350 g mass (<1 lb)  in mediastinum:

4. Heart Anatomy - 2  Heart  rests on superior surface of diaphragm  anterior to vertebral column  posterior to sternum  just left of midsternal line

5. Base & Apex of Heart

6. Coverings of the Heart  Pericardium: dbl-walled sac that heart is in  2 layers: 1. Fibrous Pericaridum: dense CT  protection  anchors heart to surrounding structures  prevents overfilling of heart with blood 2. Serous Pericardium:2 layers  Parietal layer: lines internal surface of fibrous pericardium  Visceral layer = epicardium

7. Coverings of the Heart - 2 2. Serous Pericardium: 2 layers  forms closed sac around heart = pericardial cavity  contains serous fluid: lubricates, decreasing friction of moving pumping heart  Parietal layer: lines internal surface of fibrous pericardium  Visceral layer = epicardium covers heart

9. Layers of Heart Wall  3 layers: 1. Epicardium = visceral layer of serous pericardium 2. Myocardium: cardiac muscle 3. Endocardium : squamous epithelium lining chambers of the heart

11. Chambers of the Heart  2 superior atria  separated by interatrial septum  2 larger ventricles  separated by interventricular septum 2 grooves seen on exterior view of heart: 1. Coronary sulcus between upper & lower chambers 2. Anterior/Posterior Interventricular Sulcus between ventricles

13. Atria right & left both have wrinkled, protruding appendages = auricles “little ear” Right Atrium: 2 internal features: 1. posterior wall is smooth 2. anterior wall has ridges of muscle = pectinate muscles Left Atrium: pectinate muscles only in its auricle

16. Fossa Ovalis  depression in interatrial septum  marks opening of foramen ovale =“oval window” an opening in fetal heart that shunted blood from right  left atrium (blood does not go to lung for oxygenation until birth)

18. Functions of Atria  receiving chambers of the heart  Right:  forms anterior surface of heart  deoxygenated blood from all parts of body through inferior & superior vena cavas and from the coronary sinus = venous blood from myocardium  Left:  oxygenated blood from lungs through pulmonary veins

19. Ventricle Features  Trabeculae Carnae:  irregular ridges of muscle on internal walls  Papillary Muscles:  conelike muscle bundles attached to heart valves via cordae tendinae

20. Functions of the Ventricles  receive blood from atria  Right Ventricle: pumps deoxygenated blood to lungs through pulmonary trunk  pulmonary arteries  Left Ventricle: pumps oxygenated blood to entire body through aorta

22. Heart Valves  blood flows through the heart in one direction: atria  ventricle  valves connected to papillary muscles by chordae tendinae  1 way direction due to 4 heart valves  open/close in response to differences in BP on their 2 sides  https://www.youtube.com/watch?v=y5maHDAk zUs https://www.youtube.com/watch?v=y5maHDAk zUs

23. Atrioventricular Valves  right AV valve  3 flexible cusps  both AV valves close when ventricles contract/open when ventricles relax  left AV valve  Bicuspid valve: 2 cusps Tricuspid ValveMitral Valve

25. Semilunar (SL) Valves  right side SL valve  between right ventricle & pulmonary trunk  SL valves open when ventricles contract  left side valve  between left ventricle & aorta  SL valves close when ventricles relaxed Pulmonary Valve Aortic Valve

27. Valves  https://www.youtube.com/watch?v=2jPTt23 lRB8 https://www.youtube.com/watch?v=2jPTt23 lRB8  https://www.youtube.com/watch?v=AO_aIs WpSkI https://www.youtube.com/watch?v=AO_aIs WpSkI  https://www.youtube.com/watch?v=1hrhPww 5jKY https://www.youtube.com/watch?v=1hrhPww 5jKY  https://www.youtube.com/watch?v=AHBzu5 zhFuA https://www.youtube.com/watch?v=AHBzu5 zhFuA

28. Coronary Circulation  Base of Aorta Left Coronary A Anterior InterventricularA Circumflex Artery Right Coronary A Rt Marginal Posterior Interventricular A

29. Coronary Circulation

30. Angina Pectoris  chest pain caused by fleeting deficiency in blood delivery to myocardium  cardiac muscle fibers weakened by temporary lack of O2 but do not die

31. Myocardial Infarction MI  prolonged coronary blockage  cardiac fibers do die  dead tissue  scar tissue  http://www.dnatube.com/video/1708/Myocardi al-infarction-pathology http://www.dnatube.com/video/1708/Myocardi al-infarction-pathology

32. Energy Requirements of Cardiac Muscle  cardiac muscle fibers have more mitochondria than other muscle fibers  depend almost exclusively on aerobic respiration so cannot tolerate hypoxia for long  cardiac fibers can use glucose or fatty acids as a fuel source

33. Heart Physiology  cardiac muscle has intrinsic ability to depolarize & contract (does not require nervous system)  Autonomic fibers do alter basic rhythm

34. Coronary Conduction System  independent, coordinated activity of the heart is function of: 1. gap junctions 2. intrinsic conduction system  noncontractile cardiac cells specialized to initiate & distribute impulses throughout the heart

36. Arrhythmias  irregular heart rhythms due to abnormal electrical activity  https://health.sjm.com/arrhythmia- answers/videos-and-animations.aspx https://health.sjm.com/arrhythmia- answers/videos-and-animations.aspx  http://www.nhlbi.nih.gov/health/health- topics/topics/arr/types http://www.nhlbi.nih.gov/health/health- topics/topics/arr/types

37. Extrinsic Innervation of the Heart  Medulla Oblongata: 1. cardioacceleratory center  sympathetic fibers  SA & AV nodes 1. Cardioinhibitory center  parasympathetic fibers  SA & AV nodes

38. ECG  Electrocardiography: a graphic record of heart activity tracing the composite of all action potentials generated in nodal & contractile cells at a given time  http://www.getbodysmart.com/ap/circulato rysystem/heart/electricalevents/ecg/tutori al.html http://www.getbodysmart.com/ap/circulato rysystem/heart/electricalevents/ecg/tutori al.html

39. Heart Sounds  Auscultating thorax with stethoscope reveals 2 sounds during each heartbeat  lub-dub, pause, lub-dub  pause = heart is relaxed  “lub” = AV valves closing  louder & longer than the dub  “dub” = SL valves snap shut @ beginning of ventricular relaxation

40. Heart Sounds -2  left side valves (mitral & aortic) close slightly quicker =S1  right side valves (tricuspid & pulmonary) close ~1/4 s slower = S2  so can listen to individual valve sounds by auscultating 4 specific regions of thorax

42. Heart Sounds  affected by valves closing + flow of blood  http://www.dnatube.com/video/9217/Review- of-heart-sounds http://www.dnatube.com/video/9217/Review- of-heart-sounds  http://familymedicine.osu.edu/products/physi calexam/exam/flash/heart/heart2.cfm http://familymedicine.osu.edu/products/physi calexam/exam/flash/heart/heart2.cfm  http://www.blaufuss.org/tutorial/index1.html http://www.blaufuss.org/tutorial/index1.html

43. Heart Murmurs  abnormal heart sounds  occur when blood flow strikes obstructions  flow becomes turbulent  can be normal in young children & elderly  heart wall thinner & vibrate with rushing blood flow  often indicate valve problems  insufficiency or incompetence: valves not closing all the way  blood regurgitates  stenotic: valve not opening all the way  restricts blood flow

44. Heart Murmurs  https://www.youtube.com/watch?v=6YY3O OPmUDA https://www.youtube.com/watch?v=6YY3O OPmUDA

45. Valve Problems InsufficienyStenosis

46. Cardiac Output (CO)  amount of blood pumped out by each ventricle in 1 min.  Stroke Volume (SV) = vol of blood pumped out by 1 ventricle with each beat  correleates with force of ventricular contraction  CO = HR x SV  HR = Heart Rate (pulse)  average adult: SV = 70 mL, HR = 75  * CO = ~ 5.25 L/min

47. Cardiac Reserve  difference between resting & maximal CO  nonathletic adult = 4-5x resting CO  athletic adult = 7x resting CO

48. Tachycardia  >100 beats/min  may promote fibrillation  Causes: 1. Fever 2. Stress 3. Drugs 4. Heart disease

49. Bradycardia  <60 beats/min  Causes: 1. Hypothermia 2. Drugs 3. Parasympathetic activation 4. well-trained athlete:  endurance training  hypertrophy of cardiac muscle  increases SV  allows lower resting HR w/out changing CO

50. CHF  Congestive Heart Failure  Heart inefficient pump so circulation inadequate  Causes: 1. Coronary Atherosclerosis 2. high BP over long period of time 3. MIs 4. DCM: dilated cardiomyopathy

51. Heart Failure  1 or both sides of heart may fail  left side failure  pulmonary congestion  right side failure  peripheral congestion  if 1 side fails  greater strain on other side  whole heart fails  Treatment: 1. removing excess fluid: diuretics 2. reducing BP 3. increasing contractility with digitalis 4. Heart transplant

53. Cardiac Tamponade  fluid build-up in pericardial cavity  can lead to inability of ventricles to fill fully  heart cannot pump normally  death if not tx’d  Causes: 1. infection (bacterial or viral) causing pericarditis 2. MI 3. dissecting aortic aneurysm 4. heart surgery/ trauma

55. Development of the Heart  https://www.youtube.com/watch?v=5DIUk9 IXUaI https://www.youtube.com/watch?v=5DIUk9 IXUaI