1 Cardiovascular System

2 Size of Heart Average Size of Heart 14 cm long 9 cm wide

3 Location of Heart posterior to sternum medial to lungs anterior to vertebral column base lies beneath 2 nd rib apex at 5 th intercostal space lies upon diaphragm

4 Coverings of Heart

5 Wall of the Heart

6

7 Heart Chambers Right Atrium receives blood from inferior vena cava superior vena cava coronary sinus Left Atrium receives blood from pulmonary veins Right Ventricle receives blood from right atrium Left Ventricle receives blood from left atrium

8 Heart Valves

9 Coronal Sections of Heart

10 Heart Valves Tricuspid ValvePulmonary and Aortic Valve

11 Skeleton of Heart fibrous rings to which the heart valves are attached

12 Path of Blood Through the Heart

13 Path of Blood Through the Heart

14 Blood Supply to Heart

15 Blood Supply to Heart

16 Angiogram of Coronary Arteries

17 Heart Actions Atrial Systole/Ventricular Diastole Atrial Diastole/Ventricular Systole

18 Cardiac Cycle Atrial Systole/Ventricular Diastole blood flows passively into ventricles remaining 30% of blood pushed into ventricles A-V valves open/semilunar valves close ventricles relaxed ventricular pressure increases

19 Cardiac Cycle Ventricular Systole/Atrial diastole A-V valves close chordae tendinae prevent cusps of valves from bulging too far into atria atria relaxed blood flows into atria ventricular pressure increases and opens semilunar valves blood flows into pulmonary trunk and aorta

20 Heart Sounds Lubb first heart sound occurs during ventricular systole A-V valves closing Dupp second heart sound occurs during ventricular diastole pulmonary and aortic semilunar valves closing Murmur – abnormal heart sound

21 Heart Sounds

22 Cardiac Muscle Fibers Cardiac muscle fibers form a functional syncytium group of cells that function as a unit atrial syncytium ventricular syncytium

23 Cardiac Conduction System

24 Cardiac Conduction System

25 Muscle Fibers in Ventricular Walls

26 Electrocardiogram recording of electrical changes that occur in the myocardium used to assess heart’s ability to conduct impulses P wave – atrial depolarization QRS wave – ventricular depolarization T wave – ventricular repolarization

27 Electrocardiogram

28 Electrocardiogram A prolonged QRS complex may result from damage to the A-V bundle fibers

29 Cardiac Cycle

30 Regulation of Cardiac Cycle Autonomic nerve impulses alter the activities of the S-A and A-V nodes

31 Regulation of Cardiac Cycle physical exercise body temperature concentration of various ions potassium calcium parasympathetic impulses decrease heart action sympathetic impulses increase heart action cardiac center regulates autonomic impulses to the heart Additional Factors that Influence HR

32 Blood Vessels arteries carry blood away from ventricles of heart arterioles receive blood from arteries carry blood to capillaries capillaries sites of exchange of substances between blood and body cells venules receive blood from capillaries veins carry blood toward ventricle of heart

33 Arteries and Arterioles Artery thick strong wall endothelial lining middle layer of smooth muscle and elastic tissue outer layer of connective tissue carries blood under relatively high pressure Arterioles thinner wall than artery endothelial lining some smooth muscle tissue small amount of connective tissue helps control blood flow into a capillary

34 Walls of Artery and Vein

35 Arteriole smallest arterioles only have a few smooth muscle fibers capillaries lack muscle fibers

36 Metarteriole connects arteriole directly to venule

37 Capillaries smallest diameter blood vessels extensions of inner lining of arterioles walls are endothelium only semipermeable sinusoids – leaky capillaries

38 Capillary Network

39 Regulation of Capillary Blood Flow Precapillary sphincters may close a capillary respond to needs of the cells low oxygen and nutrients cause sphincter to relax

40 Exchange in the Capillaries water and other substances leave capillaries because of net outward pressure at the capillaries’ arteriolar ends water enters capillaries’ venular ends because of a net inward pressure substances move in and out along the length of the capillaries according to their respective concentration gradients

41 Venules and Veins Venule thinner wall than arteriole less smooth muscle and elastic tissue than arteriole Vein thinner wall than artery three layers to wall but middle layer is poorly developed some have flaplike valves carries blood under relatively low pressure serves as blood reservoir

42 Venous Valves

43 Characteristics of Blood Vessels

44 Blood Volumes in Vessels

45 Arterial Blood Pressure Blood Pressure – force the blood exerts against the inner walls of the blood vessels Arterial Blood Pressure rises when ventricles contract falls when ventricles relax systolic pressure – maximum pressure diastolic pressure – minimum pressure

46 Pulse alternate expanding and recoiling of the arterial wall that can be felt

47 Factors That Influence Arterial Blood Pressure

48 Control of Blood Pressure Controlling cardiac output and peripheral resistance regulates blood pressure

49 Control of Blood Pressure If blood pressure rises, baroreceptors initiate the cardioinhibitory reflex, which lowers the blood pressure

50 Control of Blood Pressure Dilating arterioles helps regulate blood pressure

51 Venous Blood Flow not a direct result of heart action dependent on skeletal muscle contraction breathing venoconstriction

52 Central Venous Pressure pressure in the right atrium factors that influence it alter flow of blood into the right atrium affects pressure within the peripheral veins weakly beating heart increases central venous pressure increase in central venous pressure causes blood to back up into peripheral vein

53 Pulmonary Circuit consists of vessels that carry blood from the heart to the lungs and back to the heart

54 Blood Flow Through Alveoli cells of alveolar wall are tightly joined together the high osmotic pressure of the interstitial fluid draws water out of them

55 Systemic Circuit composed of vessels that lead from the heart to all body parts (except the lungs) and back to the heart includes the aorta and its branches includes the system of veins that return blood to the right atrium

56 Major Vessels of Arterial System

57 Major Blood Vessels of the Heart

58 Principal Branches of the Aorta

59 Abdominal Aorta and Its Major Branches

60 Arteries to Neck, Head, and Brain

61 Cerebral Arterial Circle Circle of Willis formed by anterior and posterior cerebral arteries, which join the internal carotid arteries

62 Arteries to Shoulder and Upper Limb

63 Arteries to Thoracic Wall

64 Arteries to Pelvic Region

65 Arteries to the Lower Limb

66 Major Vessels of the Venous System

67 Major Veins of the Brain, Head and Neck

68 Veins from the Upper Limb and Shoulder

69 Veins That Drain the Thoracic Wall

70 Veins That Drain the Abdominal Viscera

71 Veins from the Abdominal Viscera: Hepatic Portal Vein Hepatic portal vein drains one set of capillaries and leads to another set

72 Veins of the Lower Limb and Pelvis

73 Life-Span Changes cholesterol deposition in blood vessels heart enlargement death of cardiac muscle cells increase in fibrous connective tissue of the heart increase in adipose tissue of the heart increase in blood pressure decrease in resting heart rate

74 Clinical Application Arrhythmias Ventricular fibrillation rapid, uncoordinated depolarization of ventricles Tachycardia rapid heartbeat Atrial flutter rapid rate of atrial depolarization