1. Cardiovascular
Anatomy and Physiology
Reference: Pathophysiology by Kathryn McCance
Mindy Milton, MPA, PA-C
July 13, 2010
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2. Objectives
 Brief review of the structure of the heart and
vascular system
 Blood flow through the heart and body
 Chambers
 Valves
 Pulmonary circulation
 Systemic circulation
 Coronary circulation
 Electrical conduction through the heart
 Specialized cells
 Automaticity
 Rhythmicity
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3. Objectives
 Cardiac Action Potential
 Four phases 0-4
 ECG
 Cardiac cycle
 Diastole
 Systole
 Cardiac Workload
 Cardiac Output
 ANS, Hormones
 Frank-Starling Law
 LaPlace’s Law
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4. Objectives
 Cardiac Workload
 Preload - blood coming back to the heart.
 Afterload
 Structure of blood vessels
 Blood flow
 Capillary exchange
 Blood pressure
 C.O.
 Stroke Volume
 PVR
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5. Cardiovascular System
 Heart is a four chambered pump
 Blood vessels are the tubes
 Purpose is life – supplies oxygen and nutrients
to every cell and clears C02 and wastes
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6. Cardiac Muscle
 Cell
 Bundles of myofibrils
 Junctions – intercalated discs
 Rapid syncytial contraction
 Sacromere – functional unit
 Z line to Z line
 Actin and myosine bands
 Optimum length 2.2 – 2.4 µm
 T-tubules
 Communicates with ECF
 Majority of Ca++
 Sarcoplasm Reticulum
 Ca++ storage
 Mitrochondria
 Energy = ATP
 Aerobic respiration
 Oxygen
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7. Myocardial Cells
 Nearly identical to skeletal muscle cells
 Intercalated disks - desmosomes,
 Actin, myosin, and the troponin-tropomyosin
complex
troponin - tested for
 Troponin T, I, and C with MI
 Myocardial metabolism
 Myocardial oxygen consumption
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8. Myocardial Contraction and
Relaxation
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9. Circulatory System
 Heart
 Right heart
 Pumps blood through the lungs (pulmonary
circulation)
 Left heart
 Pumps blood through the systemic circulation
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10. Circulatory System
 Heart
 Mediastinum
 Heart wall
 Pericardium
 Parietal and visceral
 Pericardial cavity and fluid
 Myocardium
 Endocardium
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11. The Heart Wall
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12. The Chambers of the Heart
 Right atrium
 Left atrium
 Right ventricle
 Left ventricle
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13. The Chambers of the Heart
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14. Normal Intracardiac Pressures
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15. The Valves of the Heart
 Atrioventricular valves
 Tricuspid valve
 Bicuspid valve (Mitral)
 Semilunar valves
 Pulmonic semilunar valve
 Aortic semilunar valve
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16. The Valves of the Heart
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17. The Great Vessels
 Superior and inferior venae cavae
 Aorta
 Pulmonary artery (trunk)
 Right and left pulmonary arteries
 Blood from right ventricle
 Pulmonary veins
 Four, two from left and right lung fields
 Blood enters left atrium
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18. Blood Flow
 Cardiac cycle
 Diastole - 70 % of the blood comes in passively. Then last filling from atrial kick.
 Systole
 Phases of the cardiac cycle
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19. Phases of the cardiac cycle
 1 – Systole with isovolumetric contraction
 AV closed and SL not open yet
 Increased intraventricular pressure
 Blood volume unchanged
 2 – LV pressure > aortic pressure
 SL open and blood ejected
 Rapid ventricle pressure and volume decrease
 3 – Diastole with isovolumetric relaxation
 SL close and AV not open yet
 Decreased intraventricular pressure
 Blood volume unchanged
 4- LV pressure < LA pressure
 AV open and ventricle fills
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20. Blood Flow
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21. Normal Intracardiac Pressures
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22. The Coronary Vessels
 Right coronary artery (RCA)
 Conus
 Right marginal branch
 Posterior descending branch
 Left coronary artery (LCA)
 Left anterior descending artery (LAD)
 Circumflex artery (LCX)
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23. The Coronary Vessels
 Collateral arteries
 Coronary capillaries
 Coronary veins
 Coronary sinus
 Great cardiac vein
 Posterior vein of the left ventricle
 Coronary lymphatic vessels
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24. The Coronary Vessels
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25. Structures That Control Heart
Action
 Cardiac action potentials
 Conduction system
 Sinoatrial node (SA) - 60-100
 Intranodal pathways
 DELAY
 Atrioventricular node (AV)
 Bundle of His (AV bundle)
 Right and left bundle branches
 Purkinje fibers
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26. Conduction System of the Heart
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27. Structures That Control Heart
Action
 Cardiac excitation
 Propagation of cardiac action potentials
 Depolarization – Na and Ca
 Repolarization - K
 Electocardiogram
 Automaticity
 Spontaneous depolarization = no stimulus
 SA node, AV node, ventricles
 Rhythmicity
 Regular AP generation by conduction system
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28. Cardiac Action Potential
 Four phases
 Resting phase (4) cell membrane is relatively
impermeable to sodium. Electrical differences are
maintained by NA and K pump
 Phase 0: rapid depolarization with increase permeability
to NA with increasing positive potential
 Phase 1: Rapid decrease in Na movement
 Phase 2: increased calcium movement
 Phase 3: rapid repolarization with movement of K out of
the cell
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29. Ventricle Action Potential
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30. Comparison of Action Potential
 Skeletal AP
 Skeletal force
 Cardiac AP
 Allows ventricle filling
 Cardiac force
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31. Action Potential
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32. SA Node depolarization
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33. ECG Tracing
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34. Cardiac Cycle
 Concepts:
 Systole: contraction phase of the heart
 Diastole: relaxation and filling phase of the heart
 Blood moves from areas of higher to lower pressure
 Valves between cardiac chambers also respond to pressure
changes
 Heart rate will impact the length of each phase of the
cardiac cycle. (Increased heart rate all phases will be
shortened
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36. Cardiac Cycle
 Systole
 Aortic and pulmonic
valves are open
 Contraction phase of the
heart
 Responsible for stroke
volume
 Stroke volume 70-80 cc
with residual volume of
50-60cc
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37. Cardiac Cycle
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38. CARDIAC WORKLOAD
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39. Control of Cardiac Output
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40. Autonomic Control of CO
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41. Cardiac Workload
 Frank-Starling Law of the heart
 Increased stretch, increase force of contraction
 The amount of blood in the ventricle at end of
diastole (EDV) is directly related to the
contraction force of the next systole assuming
function of heart remains constant
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42. Cardiac Workload
 Laplace’s Law
 Amount of ventricle wall tension to produce a
certain pressure depends on size/radius of
chamber and wall thickness.
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43. Cardiac Workload
 Afterload - systemic blood pressure.
 PVR
 Resistance to left ventricular ejection of blood
 Heart rate
 Neural control mechanisms
 Thyroid Hormones
 Increased HR will increase Oxygen demand.
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44. Structures That Control Heart
Action
 Cardiac innervation
 Sympathetic nerves
 Parasympathetic nerves
 Adrenergic receptor function
 α- or β-adrenergic receptors
 Norepinephrine or epinephrine
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45. Autonomic Innervation of the
Cardiovascular System
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46. Systemic Circulation
 Macrocirculation
 Arteries
 High pressure
 Elastin
 Smooth muscle
 Veins
 Thin walled
 Low pressure
 valves
 Microcirculation
 Arterioles
 Metarterioles – pre-capillary sphincter
 Capillaries
Microcirc are the major
 Hydrostatic and oncotic pressures contributors the the
 Venules peripheral vascular
resistance
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47. Factors Affecting Blood Flow
 Poiseuille law
 Pressure
 Force of walls exerted on a liquid per unit area
 Resistance
 Opposition to force
 Diameter and length of the blood vessels
contribute to resistance
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48. Factors Affecting Blood Flow
 Velocity
 Laminar vs. turbulent flow
 Vascular compliance
 C=VP
 If there is an increase in volume, there is a
compliance of the vessel to accommodate an
increase in pressure.
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49. Laminar vs. Turbulent Flow
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50. Regulation of Blood Pressure
 Arterial pressure
 Mean arterial pressure (MAP)
 MAP = DP + 1/3(SP-DP) --> 90. High is 120-60.
 Effects of cardiac output (CO)
 Effects of total peripheral resistance (TPR)
 Effects of hormones and Peptides
 Epinephrine and norepinephrine - constriction.
 Antidiuretic hormone, renin-angiotensin-aldosterone
system, and
 natriuretic peptides(opposite of Angiotensin II, Aldo)
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51. Regulation of Coronary Circulation
 Coronary perfusion pressure (CPP)
 Difference in the aorta pressure and the pressure
in the right atrium coronary vessels
 Autoregulation
 Metabolic overrides neurogenic
 Systemic and coronary
 Autonomic regulation
 SNS/PNS
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52. Lymphatic System
 Special vascular system that picks up excess
fluid and returns it to the bloodstream
 Lymphatic fluid
 Lymphatic veins and venules - pick up a lot of
fluid.
 Right lymphatic duct
 Thoracic duct
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53. Lymphatic System
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54. Questions?
 Thanks for your attention..
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