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Lecture NotesLecture NotesChapter 17 Chapter 17

Functional Anatomy of Functional Anatomy of the Cardiovascular the Cardiovascular

SystemSystem

Copyright © 2007, 1998 by Mosby, Inc., an affiliate of Elsevier Inc.

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Gross Anatomy of the HeartGross Anatomy of the Heart

Lies in mediastinum behind sternumLies in mediastinum behind sternum Apex points to the leftApex points to the left Point of maximal impact (PMIPoint of maximal impact (PMI))

The apical beatThe apical beat 5th Intercostal space5th Intercostal space

at mid-clavicular lineat mid-clavicular line Causes of PMI shiftCauses of PMI shift

• Left Sided PneumothoraxLeft Sided Pneumothorax

• Pg. 301Pg. 301

Copyright © 2007, 1998 by Mosby, Inc., an affiliate of Elsevier Inc.

ConceptQuestion17-1

ConceptQuestion17-1

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Clinical Focus 17-1Clinical Focus 17-1 32 y.o. man. Severe chest wall injury sustained in 32 y.o. man. Severe chest wall injury sustained in

automobile accident. Conscious, anxious, c/o automobile accident. Conscious, anxious, c/o dyspnea and chest pain. Distending neck veins, dyspnea and chest pain. Distending neck veins, tachycardia; systolic blood pressure of 90mmHg.tachycardia; systolic blood pressure of 90mmHg.

Read the discussion (pg. 304)Read the discussion (pg. 304)1. The patient exhibits signs of ________________1. The patient exhibits signs of ________________

2. What is this disease?2. What is this disease?

3. Cause of distended neck veins?3. Cause of distended neck veins?

4. Cause of increased HR?4. Cause of increased HR?

5. Cause of low systolic pressure?5. Cause of low systolic pressure?

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PericardiumPericardium Loose-fitting membranous sacLoose-fitting membranous sac

Parietal vs. visceral pericardium (epicardium)Parietal vs. visceral pericardium (epicardium) Pg. 302Pg. 302

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Parietal = outter sacParietal = outter sac Visceral (epicardium) = innerVisceral (epicardium) = inner

The fluid in between = pericardial fluid… Acts The fluid in between = pericardial fluid… Acts as lubrication allowing for smoother, as lubrication allowing for smoother, frictionless movement as the heart beats.frictionless movement as the heart beats.

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Anatomy of the HeartAnatomy of the Heart Heart wallHeart wall

Epicardium, Myocardium, EndocardiumEpicardium, Myocardium, Endocardium Myocardium = Myocardium =

Heart chambers and valvesHeart chambers and valves 2 atria and 2 ventricles2 atria and 2 ventricles RA receives deoxygenated blood from RA receives deoxygenated blood from

superior vena cava, inferior vena cavasuperior vena cava, inferior vena cava LA receives oxygenated blood from LA receives oxygenated blood from

pulmonary veinspulmonary veins

• Greater muscle mass than the right Greater muscle mass than the right ventricleventricle

Copyright © 2007, 1998 by Mosby, Inc., an affiliate of Elsevier Inc.

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Anatomy of the HeartAnatomy of the Heart

Copyright © 2007, 1998 by Mosby, Inc., an affiliate of Elsevier Inc.

Fig. 17-3

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Anatomy of the HeartAnatomy of the Heart Heart chambers and valvesHeart chambers and valves

Atrial-ventricular valvesAtrial-ventricular valves• Tricuspid = Right or Left side?Tricuspid = Right or Left side?

• Mitral = Right or Left side?Mitral = Right or Left side?

• PURPOSE = prevent back flow of blood during ventricle PURPOSE = prevent back flow of blood during ventricle contractionscontractions

Ventricular outflowVentricular outflow pg 302pg 302

• Right Ventricle Pumps through Right Ventricle Pumps through __________________________________

• Left Ventricle Pumps through Left Ventricle Pumps through ____________________________________

• Prevents backflow of blood into the ventricles Prevents backflow of blood into the ventricles during ventricle relaxation during ventricle relaxation

ConceptQuestion 17-2

ConceptQuestion 17-2

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Clinical Focus 17-3Clinical Focus 17-3Mitral Valve StenosisMitral Valve Stenosis

Person with Severe Mitral Valve Stenosis Person with Severe Mitral Valve Stenosis requires oxygen and shows signs of requires oxygen and shows signs of pulmonary edema.pulmonary edema.

What is Pulmonary Edema?What is Pulmonary Edema?

What is the connection of a cardiac problem What is the connection of a cardiac problem leading to a pulmonary problem?leading to a pulmonary problem?

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Clinical Focus 17-2Clinical Focus 17-2Ventricular Septal Defect (VSD)Ventricular Septal Defect (VSD)

What is it?What is it? Mixing of blood from the two chambersMixing of blood from the two chambers

Treatment?Treatment? If patient is symptomatic (SOB), it will need If patient is symptomatic (SOB), it will need

surgical correction.surgical correction.

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Coronary CirculationCoronary CirculationThough the heart pumps blood, it also Though the heart pumps blood, it also receives oxygenated blood to sustain itselfreceives oxygenated blood to sustain itself

Coronary arteriesCoronary arteries Left and right coronariesLeft and right coronaries

• 1. Right coronary is the dominant blood supplier1. Right coronary is the dominant blood supplier

• 2. Originate immediately above aortic semilunar valve2. Originate immediately above aortic semilunar valve

• 3. “The heart relies almost exclusively on the two main 3. “The heart relies almost exclusively on the two main coronary arteries.” pg 305coronary arteries.” pg 305

In the heart, there is a lack of collateral circulation In the heart, there is a lack of collateral circulation if…if…

1. If blood flow is blocked = ischemia (tissue hypoxia) and 1. If blood flow is blocked = ischemia (tissue hypoxia) and central chest pain (angina pectoris)central chest pain (angina pectoris)

2. Myocardial infarction (MI) = heart muscle tissue death2. Myocardial infarction (MI) = heart muscle tissue death

MONA – Morphine, Oxygen, Nitroglycerin(vasodilator), MONA – Morphine, Oxygen, Nitroglycerin(vasodilator), Asprin (prevent blood clot)Asprin (prevent blood clot)

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Angina Pectoris Angina Pectoris pg 306pg 306

Aka Chest PainAka Chest Pain

Caused by: Coronary artery diseaseCaused by: Coronary artery disease

The pain is often felt beneath the sternum, in the left The pain is often felt beneath the sternum, in the left arm, and in the neckarm, and in the neck

““About 35% of all deaths in the United States are About 35% of all deaths in the United States are caused by coronary artery disease” (CAD) pg. 306caused by coronary artery disease” (CAD) pg. 306

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Coronary CirculationCoronary Circulation pg 307pg 307 Coronary veinsCoronary veins

Flow parallel to arteriesFlow parallel to arteries Empty into right atrium (coronary sinus)Empty into right atrium (coronary sinus)

Oxygen requirement and blood flowOxygen requirement and blood flow OO22 extraction extraction ≈≈70% (compare to 25% whole body)70% (compare to 25% whole body)

during exercise = during exercise = coronary flow coronary flow OO22 need governs coronary blood flow need governs coronary blood flow

Tachycardia is a response by the heart that it needs more Tachycardia is a response by the heart that it needs more oxygen oxygen

During exercise, because the heart can’t extract more oxygen from the During exercise, because the heart can’t extract more oxygen from the supply it’s getting… It needs to increase the blood flow by increasing the supply it’s getting… It needs to increase the blood flow by increasing the heart rate and get oxygen more quickly.heart rate and get oxygen more quickly.

If you give the patient oxygen, the heart rate will come back down.If you give the patient oxygen, the heart rate will come back down.Copyright © 2007, 1998 by Mosby, Inc., an affiliate of Elsevier Inc.

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Cardiac Conduction SystemCardiac Conduction System

pg 309pg 309 Specialized cardiac muscle tissue (not neurons)Specialized cardiac muscle tissue (not neurons) Atria contract at last second (“atrial kick”) to complete Atria contract at last second (“atrial kick”) to complete

ventricular fillingventricular filling ConductionConduction

Sinoatrial node (SA node) – Initiates Electrical Impulses. Travel Sinoatrial node (SA node) – Initiates Electrical Impulses. Travel down to the AV Node.down to the AV Node.

Atrioventricular node (AV node) - Triggers initial contraction of Atrioventricular node (AV node) - Triggers initial contraction of ventricles. Trigger travels down the AV bundle.ventricles. Trigger travels down the AV bundle.

AV bundle aka “bundle of His”. The AV Bundle triggers down the AV bundle aka “bundle of His”. The AV Bundle triggers down the right and left bundle branches.right and left bundle branches.

Bundle branches terminate into the Purkinje fibersBundle branches terminate into the Purkinje fibers Purkinje fibers carry the electrical signal to the ventricles (apex of Purkinje fibers carry the electrical signal to the ventricles (apex of

the heart).the heart). Ventricles receive signal and contract.Ventricles receive signal and contract.

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Systole vs. DiastoleSystole vs. Diastole

Copyright © 2007, 1998 by Mosby, Inc., an affiliate of Elsevier Inc.

DiastoleVentricle is relaxed and

fills with blood

DiastoleVentricle is relaxed and

fills with blood

SystoleVentricle contractsand ejects blood

SystoleVentricle contractsand ejects blood

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ExampleExample

In the _____________ phase, the mitral valve In the _____________ phase, the mitral valve and tricuspid valve is open, but the semilunar and tricuspid valve is open, but the semilunar valves remain closed.valves remain closed.

A. AorticA. Aortic

B. DiastolicB. Diastolic

C. SystolicC. Systolic

D. AnacroticD. Anacrotic

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ExampleExample

In the ______________ phase, the mitral In the ______________ phase, the mitral valve and tricuspid valve remain closed, but valve and tricuspid valve remain closed, but the semilunar valves open. the semilunar valves open.

A. AorticA. Aortic

B. DiastolicB. Diastolic

C. SystolicC. Systolic

D. AnacroticD. Anacrotic

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Cardiac Conduction SystemCardiac Conduction System

Fig. 17-10

TimeTime

“Stalls” for“Stalls” for

TimeTime

Total Time From Electrical Signal To Ventricular Contraction = Total Time From Electrical Signal To Ventricular Contraction =

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Cardiac CycleCardiac Cycle Cardiac Cycle refers to a complete pumping cycleCardiac Cycle refers to a complete pumping cycle

Contraction (systole) and relaxation (diastole)Contraction (systole) and relaxation (diastole) Beginning of Systole to the end of diastole = 0.8 secondsBeginning of Systole to the end of diastole = 0.8 seconds

Ventricular filling PRELOADVentricular filling PRELOAD 80% passive + 20% atrial “kick”80% passive + 20% atrial “kick” 80% is blood flowing from atria into ventricle80% is blood flowing from atria into ventricle At the last moment, the atria kicks 20% more blood into the At the last moment, the atria kicks 20% more blood into the

ventricle to get the ventricle ready to pumpventricle to get the ventricle ready to pump Ventricular emptying (contraction) AFTERLOADVentricular emptying (contraction) AFTERLOAD

Closure of the AV valves (1st heart sound)Closure of the AV valves (1st heart sound) Isovolumetric contraction (all valves closed)Isovolumetric contraction (all valves closed) Resistance to ejection = afterloadResistance to ejection = afterload pg pg

316316

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Volume of blood during cardiac cycleVolume of blood during cardiac cycle Ventricular filling PRELOADVentricular filling PRELOAD

120 mL of blood total in this phase120 mL of blood total in this phase ““End-Diastolic” VolumeEnd-Diastolic” Volume

Ventricular emptying (contraction) AFTER LOADVentricular emptying (contraction) AFTER LOAD Normal amount of blood that is ejected = Stroke volume = 70 Normal amount of blood that is ejected = Stroke volume = 70

mLmL How much is left in the ventricle?How much is left in the ventricle?

• 50mL50mL

• = “End-Systolic” Volume (Not the same as stroke volume)= “End-Systolic” Volume (Not the same as stroke volume)

Cycle repeats itself and the ventricle is filled back up Cycle repeats itself and the ventricle is filled back up to 120mL in the preload phase.to 120mL in the preload phase.

If 70mL out of 120mL is ejected, what’s the If 70mL out of 120mL is ejected, what’s the percentage of ejected blood?percentage of ejected blood?

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… … this is known as…this is known as… EJECTION FRACTIONEJECTION FRACTION Ejection fraction… Percentage is 58 or about Ejection fraction… Percentage is 58 or about

60%. (Normal 60%. (Normal ≈≈ 60%.) 60%.) A low ejection fraction = A low ejection fraction = Indicates = Less than 50%Indicates = Less than 50%

indicates poor contractility and pumping failureindicates poor contractility and pumping failure

On the flip side, during exercise, the ejection On the flip side, during exercise, the ejection fraction may increase up to 90%fraction may increase up to 90% pg pg 316316

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From Previous SlideFrom Previous Slide

Ventricular emptying (contraction) AFTER LOADVentricular emptying (contraction) AFTER LOAD Normal amount of blood that is ejected = Stroke volume = 70 mLNormal amount of blood that is ejected = Stroke volume = 70 mL How much is left in the ventricle?How much is left in the ventricle?

• 50mL50mL

• = “End-Systolic” Volume (Not the same as stroke volume)= “End-Systolic” Volume (Not the same as stroke volume)

Two ways to calculate Stroke VolumeTwo ways to calculate Stroke Volume

1. Cardiac Output(mL) / HR1. Cardiac Output(mL) / HR

2. Preload – Afterload2. Preload – Afterload

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Determining Stroke VolumeDetermining Stroke VolumeCardiac Output(mL) / HRCardiac Output(mL) / HR

Example:Example:

C.O = 5L/minC.O = 5L/min

HR = 80/minHR = 80/min

S.V. = ____ mLS.V. = ____ mL

Example:Example:

C.O. = 3 L/minC.O. = 3 L/min

HR = 120/minHR = 120/min

S.V. = ______ mLS.V. = ______ mL

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Determining Stroke VolumeDetermining Stroke Volume

The following information is obtained:The following information is obtained:HR 120/minHR 120/minPreload volume 120mLPreload volume 120mLAfterload Volume 80mLAfterload Volume 80mLB/P 109/75mmHgB/P 109/75mmHg

What is the stroke volume?What is the stroke volume?A. 210mLA. 210mLB. 90mLB. 90mLC. 50mLC. 50mL D. 40mLD. 40mL Preload – Afterload (D)Preload – Afterload (D)

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SummarySummary

Which of the following is known as end-Which of the following is known as end-diastolic volume?diastolic volume?

A. AfterloadA. Afterload

B. Stroke VolumeB. Stroke Volume

C. PreloadC. Preload

D. DiastoleD. Diastole

C. PreloadC. Preload Go back 5 slides agoGo back 5 slides ago

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Regulation of Pumping ActivityRegulation of Pumping Activity Normally, the blood that comes in (Right Atrium) is Normally, the blood that comes in (Right Atrium) is

pumped out (Left Ventricle) at the same ratepumped out (Left Ventricle) at the same rate

The heart has the ability to adapt to inflow The heart has the ability to adapt to inflow changeschanges ““Frank-Starling Mechanism”Frank-Starling Mechanism”

The heart may lose its ability to adapt is the left The heart may lose its ability to adapt is the left ventricle’s muscle has been over stretchedventricle’s muscle has been over stretched Left Ventricle FailsLeft Ventricle Fails Blood backs upBlood backs up Congestive Heart FailureCongestive Heart Failure pg 314pg 314