Cardiovascular System 1 Size of Heart Average Size

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Cardiovascular System 1

Cardiovascular System 1

Size of Heart Average Size of Heart • 14 cm long • 9 cm

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

Location of Heart • posterior to sternum • medial to lungs • anterior to

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 3

Coverings of Heart 4

Coverings of Heart 4

Wall of the Heart 5

Wall of the Heart 5

Wall of the Heart 6

Wall of the Heart 6

Heart Chambers Right Atrium • receives blood from • inferior vena cava • superior

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

Heart Valves 8

Heart Valves 8

Coronal Sections of Heart 9

Coronal Sections of Heart 9

Heart Valves Tricuspid Valve Pulmonary and Aortic Valve 10

Heart Valves Tricuspid Valve Pulmonary and Aortic Valve 10

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

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

Path of Blood Through the Heart 12

Path of Blood Through the Heart 12

Path of Blood Through the Heart 13

Path of Blood Through the Heart 13

Blood Supply to Heart 14

Blood Supply to Heart 14

Blood Supply to Heart 15

Blood Supply to Heart 15

Angiogram of Coronary Arteries 16

Angiogram of Coronary Arteries 16

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

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

Cardiac Cycle Atrial Systole/Ventricular Diastole • blood flows passively into ventricles • remaining 30%

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 18

Cardiac Cycle Ventricular Systole/Atrial diastole • A-V valves close • chordae tendinae prevent cusps

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 19

Heart Sounds Lubb • first heart sound • occurs during ventricular systole • A-V

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 20

Heart Sounds 21

Heart Sounds 21

Cardiac Muscle Fibers Cardiac muscle fibers form a functional syncytium • group of cells

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

Cardiac Conduction System 23

Cardiac Conduction System 23

Cardiac Conduction System 24

Cardiac Conduction System 24

Muscle Fibers in Ventricular Walls 25

Muscle Fibers in Ventricular Walls 25

Electrocardiogram • recording of electrical changes that occur in the myocardium • used to

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 26

Electrocardiogram 27

Electrocardiogram 27

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

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

Cardiac Cycle 29

Cardiac Cycle 29

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

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

Regulation of Cardiac Cycle Additional Factors that Influence HR • physical exercise • body

Regulation of Cardiac Cycle Additional Factors that Influence HR • 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 31

Blood Vessels • arteries • carry blood away from ventricles of heart • arterioles

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

Arteries and Arterioles Artery • thick strong wall • endothelial lining • middle layer

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 33

Walls of Artery and Vein 34

Walls of Artery and Vein 34

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

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

Metarteriole connects arteriole directly to venule 36

Metarteriole connects arteriole directly to venule 36

Capillaries • smallest diameter blood vessels • extensions of inner lining of arterioles •

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

Capillary Network 38

Capillary Network 38

Regulation of Capillary Blood Flow Precapillary sphincters • may close a capillary • respond

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 39

Exchange in the Capillaries • water and other substances leave capillaries because of net

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 40

Venules and Veins Venule • thinner wall than arteriole • less smooth muscle and

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 41

Venous Valves 42

Venous Valves 42

Characteristics of Blood Vessels 43

Characteristics of Blood Vessels 43

Blood Volumes in Vessels 44

Blood Volumes in Vessels 44

Arterial Blood Pressure – force the blood exerts against the inner walls of the

Arterial 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 45

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

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

Factors That Influence Arterial Blood Pressure 47

Factors That Influence Arterial Blood Pressure 47

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

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

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

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

Control of Blood Pressure Dilating arterioles helps regulate blood pressure 50

Control of Blood Pressure Dilating arterioles helps regulate blood pressure 50

Venous Blood Flow • not a direct result of heart action • dependent on

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

Central Venous Pressure • pressure in the right atrium • factors that influence it

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 52

Pulmonary Circuit • consists of vessels that carry blood from the heart to the

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

Blood Flow Through Alveoli • cells of alveolar wall are tightly joined together •

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 54

Systemic Circuit • composed of vessels that lead from the heart to all body

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 55

Major Vessels of Arterial System 56

Major Vessels of Arterial System 56

Major Blood Vessels of the Heart 57

Major Blood Vessels of the Heart 57

Principal Branches of the Aorta 58

Principal Branches of the Aorta 58

Abdominal Aorta and Its Major Branches 59

Abdominal Aorta and Its Major Branches 59

Arteries to Neck, Head, and Brain 60

Arteries to Neck, Head, and Brain 60

Cerebral Arterial Circle • Circle of Willis • formed by anterior and posterior cerebral

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

Arteries to Shoulder and Upper Limb 62

Arteries to Shoulder and Upper Limb 62

Arteries to Thoracic Wall 63

Arteries to Thoracic Wall 63

Arteries to Pelvic Region 64

Arteries to Pelvic Region 64

Arteries to the Lower Limb 65

Arteries to the Lower Limb 65

Major Vessels of the Venous System 66

Major Vessels of the Venous System 66

Major Veins of the Brain, Head and Neck 67

Major Veins of the Brain, Head and Neck 67

Veins from the Upper Limb and Shoulder 68

Veins from the Upper Limb and Shoulder 68

Veins That Drain the Thoracic Wall 69

Veins That Drain the Thoracic Wall 69

Veins That Drain the Abdominal Viscera 70

Veins That Drain the Abdominal Viscera 70

Veins from the Abdominal Viscera: Hepatic Portal Vein Hepatic portal vein drains one set

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

Veins of the Lower Limb and Pelvis 72

Veins of the Lower Limb and Pelvis 72

Life-Span Changes • cholesterol deposition in blood vessels • heart enlargement • death of

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 73

Clinical Application Arrhythmias Ventricular fibrillation • rapid, uncoordinated depolarization of ventricles Tachycardia • rapid

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