2. Heart Anatomy Approximately the size of your fist(usually bigger) Location – Superior surface of diaphragm – Left of the midline – Anterior to the vertebral column, posterior to the sternum

3. Heart Anatomy Figure 19.1

4. Heart Covering Pericardial physiology – Protects and anchors heart – Prevents overfilling Figure 19.2

5. Heart Covering Pericardial anatomy – Fibrous pericardium – Serous pericardium (separated by pericardial cavity) – Epicardium (visceral layer) Figure 19.2

6. Heart Wall Epicardium – visceral layer of the serous pericardium Myocardium – cardiac muscle layer forming the bulk of the heart Fibrous skeleton of the heart – crisscrossing, interlacing layer of connective tissue (INCLUDING VALVES) Endocardium – endothelial layer of the inner myocardial surface

7. External Heart: Anterior View Figure 19.4b

8. Atria of the Heart Atria are the receiving chambers of the heart Each atrium has a protruding auricle Pectinate muscles mark atrial walls Blood enters right atria from superior and inferior venae cavae and coronary sinus Blood enters left atria from pulmonary veins

9. Ventricles of the Heart Ventricles are the discharging chambers of the heart Papillary muscles and trabeculae carneae muscles mark ventricular walls Right ventricle pumps blood into the pulmonary trunk Left ventricle pumps blood into the aorta

10. Gross Anatomy of Heart: Frontal Section Figure 19.4e

11. Pathway of Blood through the Heart and Lungs Right atrium  tricuspid valve  right ventricle Right ventricle  pulmonary semilunar valve  pulmonary arteries  lungs Lungs  pulmonary veins  left atrium Left atrium  bicuspid valve  left ventricle Left ventricle  aortic semilunar valve  aorta Aorta  systemic circulation

12. Pathway of Blood through the Heart and Lungs Figure 19.5

13. Heart Valves Heart valves insure unidirectional blood flow through the heart Atrioventricular (AV) valves lie between the atria and the ventricles AV valves prevent backflow into the atria when ventricles contract Chordae tendineae anchor AV valves to papillary muscles(PULL THE SHADE OPEN)

14. Heart Valves Figure 19.9

15. Heart Valves Aortic semilunar valve lies between the left ventricle and the aorta Pulmonary semilunar valve lies between the right ventricle and pulmonary trunk Semilunar valves prevent backflow of blood into the ventricles

16. Heart Valves Figure 19.10

17. Heart Physiology: Sequence of Excitation Sinoatrial (SA) node generates impulses about 75 times/minute Atrioventricular (AV) node delays the impulse approximately 0.1 second Impulse passes from atria to ventricles via the atrioventricular bundle (bundle of His)

18. Heart Physiology: Sequence of Excitation AV bundle splits into two pathways in the interventricular septum (bundle branches) – Bundle branches carry the impulse toward the apex of the heart – Purkinje fibers carry the impulse to the heart apex and ventricular walls

19. Heart Physiology: Sequence of Excitation Figure 19.14a

20. Electrocardiography Electrical activity is recorded by electrocardiogram (ECG) P wave corresponds to depolarization of atria QRS complex corresponds to ventricular depolarization T wave corresponds to ventricular repolarization Atrial repolarization record is masked by the larger QRS complex

21. Electrocardiography Figure 19.16

22. videos heart beat electricity http://medmovie.com/mmdatabase/flash/0007a.swf ecg http://medmovie.com/mmdatabase/flash/0038a.swf all animations http://science.nhmccd.edu/biol/ap2int.htm#cardio heart valves http://www.wellesley.edu/Biology/Courses/111/HeartValves.MOV visible heart video clips http://www.visibleheart.com/videoclips.html arrythmeias http://medmovie.com/mmdatabase/flash/0078a.swf heart attack http://medmovie.com/mmdatabase/flash/0072a_B.swf

23. Cardiac Cycle Cardiac cycle refers to all events associated with blood flow through the heart – Systole – contraction of heart muscle – Diastole – relaxation of heart muscle

24. Phases of the Cardiac Cycle Figure 19.19b

25. Blood Vessels Blood is carried in a closed system of vessels that begins and ends at the heart The three major types of vessels are arteries, capillaries, and veins Arteries carry blood away from the heart, veins carry blood toward the heart Capillaries contact tissue cells and directly serve cellular needs

26. Generalized Structure of Blood Vessels Arteries and veins are composed of three tunics – tunica interna, tunica media, and tunica externa Capillaries are composed of endothelium with sparse basal lamina Lumen – central blood-containing space surrounded by tunics

27. Generalized Structure of Blood Vessels Figure 20.1b

28. Tunics Tunica interna (tunica intima) – Endothelial layer that lines the lumen of all vessels – In vessels larger than 1 mm, a subendothelial connective tissue basement membrane is present Tunica media – Smooth muscle and elastic fiber layer, regulated by sympathetic nervous system – Controls vasoconstriction/vasodilation of vessels Tunica externa (tunica adventitia) – Collagen fibers that protect and reinforce vessels – Larger vessels contain vasa vasorum

29. Capillary Beds Figure 20.4a

30. Capillary Beds Figure 20.4b

31. Blood Pressure (BP) Force per unit area exerted on the wall of a blood vessel by its contained blood – Expressed in terms of millimeters of mercury (mm Hg) – Measured in reference to systemic arterial BP in large arteries near the heart The differences in BP within the vascular system provide the driving force that keeps blood moving from higher to lower pressure areas

32. Systemic Blood Pressure Figure 20.5

33. Measuring Blood Pressure Systemic arterial BP is measured indirectly with the auscultatory method – A sphygmomanometer is placed on the arm superior to the elbow – Pressure is increased in the cuff until it is greater than systolic pressure in the brachial artery – Pressure is released slowly and the examiner listens with a stethoscope – The first sounds heard is recorded as the systolic pressure – The pressure when sound disappears is recorded as the diastolic pressure

34. Alterations in Blood Pressure Hypotension – low BP in which systolic pressure is below 100 mm Hg Hypertension – condition of sustained elevated arterial pressure of 140/90 or higher – Transient elevations are normal and can be caused by fever, physical exertion, and emotional upset – Chronic elevation is a major cause of heart failure, vascular disease, renal failure, and stroke