![The Heart: Cardiac Output
Slide
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
∙ Cardiac output (CO)
∙Amount of blood pumped by each side of
the heart in one minute
∙CO = (heart rate [HR]) x (stroke volume
[SV])
∙ Stroke volume
∙Volume of blood pumped by each ventricle
in one contraction](https://image.slidesharecdn.com/circulatorysystem-230407091632-4d3e0f4f/85/CIRCULATORY-SYSTEM-pptx-2-pdf-52-320.jpg)
CIRCULATORY SYSTEM.pptx (2).pdf
- 1. Essentials of Human Anatomy & Physiology Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Seventh Edition Elaine N. Marieb Chapter 11 The Cardiovascular System
- 2. Objectives After this lesson you should have understand the following: • Functions of heart • Covering of the heart • Anatomy • Types of chambers • Blood circualation • Types of valves • Cardiac cycle • Heart circulation • Regualation of heart beat • Diffusion • Pulse and blood pressures
- 3. Development of the heart
- 4. The Cardiovascular System Slide 11.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ A closed system of the heart and blood vessels ▪ The heart pumps blood ▪ Blood vessels allow blood to circulate to all parts of the body ∙ The function of the cardiovascular system ▪ To deliver oxygen and nutrients and to remove carbon dioxide and other waste products
- 5. The Heart Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Location ∙Thorax between the lungs ∙Pointed apex directed toward left hip ∙The average gross weight of the heart ∙31-40 years, ✔ 289.6 g (men) & 284.7 g (women) ▪ 61-70 years, ✔ 345.9 g (men) & 285.1 g (women)
- 6. • Dextrocardia – Rare heart condition in which your heart points toward the right side of your chest instead of the left side
- 7. The Heart Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.1
- 8. The Heart: Coverings Slide 11.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Pericardium – a double serous membrane ∙Visceral pericardium ∙Next to heart ∙Parietal pericardium ∙Outside layer ∙ Serous fluid fills the space between the layers of pericardium
- 10. The Heart: Heart Wall Slide 11.4 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Three layers ∙Epicardium ∙Outside layer ∙This layer is the parietal pericardium ∙Connective tissue layer ∙Myocardium ∙Middle layer ∙Mostly cardiac muscle ∙Endocardium ∙Inner layer ∙Endothelium
- 11. External Heart Anatomy Slide 11.5 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.2a
- 12. The Heart: Chambers Slide 11.6 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Right and left side act as separate pumps ∙ Four chambers ∙Atria ∙Receiving chambers ∙Right atrium ∙Left atrium ∙Ventricles ∙Discharging chambers ∙Right ventricle ∙Left ventricle
- 15. Blood Circulation Slide 11.7 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.3
- 16. The Heart: Valves Slide 11.8 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Allow blood to flow in only one direction ∙ Four valves ∙Atrioventricular valves – between atria and ventricles ∙Bicuspid valve (left) ∙Tricuspid valve (right) ∙Semilunar valves between ventricle and artery ∙Pulmonary semilunar valve ∙Aortic semilunar valve
- 17. The Heart: Valves Slide 11.9 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Valves open as blood is pumped through ∙ Held in place by chordae tendineae (“heart strings”) ∙ Close to prevent backflow
- 18. Operation of Heart Valves Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.4
- 19. Valve Pathology • Incompetent valve = backflow and repump • Stenosis = stiff= heart workload increased • May be replaced • Lup Dub Heart Sound
- 20. The Heart: Associated Great Vessels Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Aorta ∙Leaves left ventricle ∙ Pulmonary arteries ∙Leave right ventricle ∙ Vena cava ∙Enters right atrium ∙ Pulmonary veins (four) ∙Enter left atrium
- 22. Coronary Circulation Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Blood in the heart chambers does not nourish the myocardium ∙ The heart has its own nourishing circulatory system ∙Coronary arteries ∙Cardiac veins ∙Blood empties into the right atrium via the coronary sinus
- 25. Cardiac Pathology • Rapid heart beat • = Inadequate blood • = Angina Pectoris
- 26. The Heart: Conduction System Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Intrinsic conduction system (nodal system) ∙Heart muscle cells contract, without nerve impulses, in a regular, continuous way
- 27. The Heart: Conduction System Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙Special tissue sets the pace ∙Sinoatrial node (right atrium) ∙Pacemaker ∙Atrioventricular node (junction of r&l atria and ventricles) ∙Atrioventricular bundle (Bundle of His) ∙Bundle branches (right and left) ∙Purkinje fibers
- 28. Heart Contractions Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.5
- 29. • Heart's sinus node ▪ Natural pacemaker (found in the upper right chamber of the heart, known as the atrium). It sends an electrical impulse to make your heart beat
- 35. • Three formations – P wave: impulse across atria – QRS complex: spread of impulse down septum, around ventricles in Purkinje fibers – T wave: end of electrical activity in ventricles Electrocardiograms (EKG/ECG)
- 41. A P wave on an electrocardiogram represents a phase of electrical activity that causes the atria of the heart to contract. on the electrocardiogram of a healthy individual. The P wave is the first wave found
- 42. • A healthy P wave is initiated in the sinoatrial node of the right atrium. • Action potentials generated at this node spread throughout the atria. • This means that the right atrium contracts slightly earlier than the left atrium.
- 43. • The heart conduction pathway in the atria is composed of the sinoatrial node, – Thorel’s bundle • Conducts action potentials from the SA node along the back of the right atrium – Wenckebach’s bundle • Through the right side and front of the right atrium. – Bachmann’s bundle • Is an extension of a group of fibers that cross far into the muscle of the left atrium. – The atrioventricular node.
- 44. Pathology of the Heart • Damage to AV node = release of ventricles from control = slower heart beat • Slower heart beat can lead to fibrillation • Fibrillation = lack of blood flow to the heart • Tachycardia = more than 100 beats/min • Bradychardia = less than 60 beats/min
- 45. • Heart conduction and contraction does not need the brain to function. • The medulla oblongata of the brainstem controls how quickly or slowly heart muscle contracts
- 46. • Pacemaker cells should only be found at the sinoatrial node (SAN) and atrioventricular node (AVN). • These cells are the captains of the cardiac pacemaker. • Regular (healthy) heart muscle cells do not display automaticity; • Ions involved in heart muscle contraction (sodium, potassium, and calcium) are imbalanced, regular cardiomyocytes may also start to generate action potentials.
- 47. • P wave: depolarization of the atria. As gravity helps blood to flow into the ventricles, less muscle contraction is required here. This is why the P wave is smaller than the R and T waves. • PR interval: a short pause before the QRS complex
- 48. • Q wave: depolarization of the top of the ventricular septum by the bundle of His. A small, downward-pointing wave. • R wave: ventricular depolarization at the thickest part of the ventricular walls via the bundle branches – this is why the R wave is the biggest (more voltage is needed).
- 49. • S wave: depolarization in the Purkinje fibers. Opposite curve direction to R wave as signals travel from the bottom of the ventricles and move upwards. • ST-segment: time required for each ventricle to completely depolarize (relax) • T wave: complete repolarization (relaxation) of the ventricles.
- 50. The Heart: Cardiac Cycle Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Atria contract simultaneously ∙ Atria relax, then ventricles contract ∙ Systole = contraction ∙ Diastole = relaxation
- 51. Filling of Heart Chambers – the Cardiac Cycle Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.6
- 52. The Heart: Cardiac Output Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Cardiac output (CO) ∙Amount of blood pumped by each side of the heart in one minute ∙CO = (heart rate [HR]) x (stroke volume [SV]) ∙ Stroke volume ∙Volume of blood pumped by each ventricle in one contraction
- 53. Cardiac output, cont. • CO = HR x SV • 5250 ml/min = 75 beats/min x 70 mls/beat • Norm = 5000 ml/min • Entire blood supply passes through body once per minute. • CO varies with demands of the body.
- 54. Cardiac Output Regulation Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.7
- 55. The Heart: Regulation of Heart Rate Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Stroke volume usually remains relatively constant ∙Starling’s law of the heart – the more that the cardiac muscle is stretched, the stronger the contraction ∙ Changing heart rate is the most common way to change cardiac output
- 56. Regulation of Heart Rate Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Increased heart rate ∙Sympathetic nervous system ∙Crisis ∙Low blood pressure ∙Hormones ∙Epinephrine ∙Thyroxine ∙Exercise ∙Decreased blood volume
- 57. The Heart: Regulation of Heart Rate Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Decreased heart rate ∙Parasympathetic nervous system ∙High blood pressure or blood volume ∙Dereased venous return ∙In Congestive Heart Failure the heart is worn out and pumps weakly. Digitalis works to provide a slow, steady, but stronger beat.
- 58. Congestive Heart Failure (CHF) • Decline in pumping efficiency of heart • Inadequate circulation • Progressive, also coronary atherosclerosis, high blood pressure and history of multiple Myocardial Infarctions • Left side fails = pulmonary congestion and suffocation • Right side fails = peripheral congestion and edema
- 59. Blood Vessels: The Vascular System Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Taking blood to the tissues and back ∙Arteries ∙Arterioles ∙Capillaries ∙Venules ∙Veins
- 60. The Vascular System Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.8b
- 61. Blood Vessels: Anatomy Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Three layers (tunics) ∙Tunic intima ∙Endothelium ∙Tunic media ∙Smooth muscle ∙Controlled by sympathetic nervous system ∙Tunic externa ∙Mostly fibrous connective tissue
- 62. Differences Between Blood Vessel Types Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Walls of arteries are the thickest ∙ Lumens of veins are larger ∙ Skeletal muscle “milks” blood in veins toward the heart ∙ Walls of capillaries are only one cell layer thick to allow for exchanges between blood and tissue
- 63. Movement of Blood Through Vessels Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Most arterial blood is pumped by the heart ∙ Veins use the milking action of muscles to help move blood Figure 11.9
- 64. Capillary Beds Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Capillary beds consist of two types of vessels ∙Vascular shunt – directly connects an arteriole to a venule Figure 11.10
- 65. Capillary Beds Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙True capillaries – exchange vessels ∙Oxygen and nutrients cross to cells ∙Carbon dioxide and metabolic waste products cross into blood Figure 11.10
- 66. Diffusion at Capillary Beds Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.20
- 67. Vital Signs • Arterial pulse • Blood pressure • Repiratory Rate • Body Temperature • All indicate the efficiency of the system
- 68. Pulse Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Pulse – pressure wave of blood ∙ Monitored at “pressure points” where pulse is easily palpated Figure 11.16
- 69. Blood Pressure Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Measurements by health professionals are made on the pressure in large arteries ∙Systolic – pressure at the peak of ventricular contraction ∙Diastolic – pressure when ventricles relax ∙ Pressure in blood vessels decreases as the distance away from the heart increases
- 70. Measuring Arterial Blood Pressure Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.18
- 71. Blood Pressure: Effects of Factors Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Neural factors ∙Autonomic nervous system adjustments (sympathetic division) ∙ Renal factors ∙Regulation by altering blood volume ∙Renin – hormonal control
- 72. Blood Pressure: Effects of Factors Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Temperature ∙Heat has a vasodilation effect ∙Cold has a vasoconstricting effect ∙ Chemicals ∙Various substances can cause increases or decreases ∙ Diet
- 73. Variations in Blood Pressure Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ∙ Human normal range is variable ∙Normal ∙140–110 mm Hg systolic ∙80–75 mm Hg diastolic ∙Hypotension ∙Low systolic (below 110 mm HG) ∙Often associated with illness ∙Hypertension ∙High systolic (above 140 mm HG) ∙Can be dangerous if it is chronic