Interesting FactsInteresting Facts

At rest, the heart pumps 30xs its own At rest, the heart pumps 30xs its own weight each minute.weight each minute.

There are 60,000 miles of blood vessels.There are 60,000 miles of blood vessels.

In one day, the heart can pump 7000 L.In one day, the heart can pump 7000 L.

In one year, the heart pumps about 5 In one year, the heart pumps about 5 million L.million L.

The average body contains about 5 L of The average body contains about 5 L of blood volume.blood volume.

Functions of the HeartFunctions of the Heart Generating Generating bloodblood pressure pressure

Routing Routing bloodblood– Heart separates pulmonary (lungs to left side) Heart separates pulmonary (lungs to left side)

and systemic (Oand systemic (O22 & nutrients) circulations & nutrients) circulations

Ensuring one-way Ensuring one-way bloodblood flow flow– Heart valves ensure one-way flowHeart valves ensure one-way flow

Regulating Regulating bloodblood supply supply– Changes in contraction rate and force match Changes in contraction rate and force match

blood delivery to changing metabolic needsblood delivery to changing metabolic needs

Size, Shape, Location Size, Shape, Location of the Heartof the Heart

Size of a closed fistSize of a closed fist

ShapeShape– ApexApex: Blunt rounded : Blunt rounded

point of cone (pointed point of cone (pointed bottom)bottom)

– BaseBase: Flat part at : Flat part at opposite of end of opposite of end of cone (rounded top)cone (rounded top)

Located in thoracic Located in thoracic cavity in cavity in mediastinum (b/w mediastinum (b/w the lungs; 2/3 to left the lungs; 2/3 to left of center) of center)

PericardiumPericardium

Encloses the heart and holds it in placeEncloses the heart and holds it in place

Two layers:Two layers:– Outer, fibrous pericardium prevents the Outer, fibrous pericardium prevents the

heart from overstretchingheart from overstretching

– The inner, serous pericardium contains The inner, serous pericardium contains pericardial fluid to prevent frictionpericardial fluid to prevent friction

Heart WallHeart Wall

Three layers:Three layers:– Epicardium—thin, transparent outer layerEpicardium—thin, transparent outer layer

– Myocardium—cardiac muscle tissue; bulk Myocardium—cardiac muscle tissue; bulk of the heartof the heart

– Endocardium—lines the inside of the Endocardium—lines the inside of the myocardium and covers the valvesmyocardium and covers the valves

Heart ChambersHeart Chambers

Two upper chambers: Two upper chambers: AtriaAtria– Receiving chambers Receiving chambers – Separated by Separated by

interatrial septuminteratrial septum

Two lower chambers: Two lower chambers: VentriclesVentricles– Pumping chambersPumping chambers– Separated by Separated by

interventricular interventricular septumseptum

Thickness of Heart Thickness of Heart ChambersChambers

Vary according to each chambers Vary according to each chambers functions.functions.

Atria—thin walls because they only pump Atria—thin walls because they only pump blood to ventriclesblood to ventricles

Right ventricle—pumps blood to lungs; Right ventricle—pumps blood to lungs; slightly bigger than atriaslightly bigger than atria

Left ventricle—pump blood to entire body Left ventricle—pump blood to entire body and keep up with the other chambers; and keep up with the other chambers; thickest of the four chambersthickest of the four chambers

Concept CheckConcept Check What are the functions of the heart?What are the functions of the heart?

– Blood pressure, routing blood, one-way Blood pressure, routing blood, one-way blood flow, regulating blood supplyblood flow, regulating blood supply

Name and describe the 3 layers of the Name and describe the 3 layers of the heart.heart.– Epicardium (thin/transparent outer layer), Epicardium (thin/transparent outer layer),

myocardium (cardiac muscle tisssue; bulk), myocardium (cardiac muscle tisssue; bulk), endocardium (lines inside of myocardium & endocardium (lines inside of myocardium & covers valves)covers valves)

What is the difference between atria and What is the difference between atria and ventricles?ventricles?– Atria receives blood; ventricles pumps blood Atria receives blood; ventricles pumps blood

Blood Vessel StructureBlood Vessel Structure ArteriesArteries

– Elastic, muscular, arteriolesElastic, muscular, arterioles

CapillariesCapillaries– Blood flows from arterioles to capillariesBlood flows from arterioles to capillaries– Most of exchange between blood and interstitial Most of exchange between blood and interstitial

spaces occurs across the wallsspaces occurs across the walls– Blood flows from capillaries to venous systemBlood flows from capillaries to venous system

VeinsVeins– Venules, small veins, medium or Venules, small veins, medium or

large veinslarge veins

Valves of the HeartValves of the Heart

Four valves one for Four valves one for each chambereach chamber– They keep blood from They keep blood from

flowing back to where flowing back to where it came from it came from

– They open and close They open and close in response to the in response to the pressure of blood pressure of blood against themagainst them

Valves of the HeartValves of the Heart Atrioventricular Atrioventricular

(cuspid) valves(cuspid) valves– Tricuspid valveTricuspid valve — —

between right atrium between right atrium and right ventricle; 3 and right ventricle; 3 flaps or cuspsflaps or cusps

– Chordae tendinaeChordae tendinae — —tendon-like cords that tendon-like cords that prevent the cusps from prevent the cusps from being pushed backbeing pushed back

– Bicuspid valveBicuspid valve — —between left atrium and between left atrium and left ventricle; two cuspsleft ventricle; two cusps

Path of BloodPath of Blood

Right atrium receives deoxygenated Right atrium receives deoxygenated blood from 3 veins:blood from 3 veins:– Superior Vena Cava—blood from above the Superior Vena Cava—blood from above the

heartheart

– Inferior Vena Cava—blood from below the Inferior Vena Cava—blood from below the heartheart

– Coronary Sinus—blood from the heart wallCoronary Sinus—blood from the heart wall

Vessels of the HeartVessels of the Heart

Right VentricleRight Ventricle Blood goes from to Blood goes from to

the the pulmonary trunkpulmonary trunk

Pulmonary trunk Pulmonary trunk divides into divides into left and left and right pulmonary right pulmonary arteriesarteries

Pulmonary arteries Pulmonary arteries lead to the lead to the lungslungs

From the LungsFrom the Lungs

Oxygenated blood Oxygenated blood enters the left enters the left atrium via atrium via four four pulmonary veinspulmonary veins

From the Left VentricleFrom the Left Ventricle

Blood enters the ascending aorta Blood enters the ascending aorta

To the coronary arteriesTo the coronary arteries

To the arch of the aortaTo the arch of the aorta

To the thoracic aortaTo the thoracic aorta

To the abdominal aortaTo the abdominal aorta

Valves of the HeartValves of the Heart

Semilunar ValvesSemilunar Valves– Pulmonary semilunar Pulmonary semilunar

valvevalve— between right — between right ventricle and ventricle and pulmonary arterypulmonary artery

– Aortic semilunar valveAortic semilunar valve— between left — between left ventricle and the ventricle and the aortaaorta

Blood Supply of the HeartBlood Supply of the Heart

Coronary Circulation—blood flow Coronary Circulation—blood flow through the myocardium through the myocardium – Left and right Left and right coronary arteriescoronary arteries bring bring

blood to the tissueblood to the tissue

– Coronary sinusCoronary sinus take deoxygenated take deoxygenated blood from the tissueblood from the tissue

Blood Flow Through HeartBlood Flow Through Heart

Concept CheckConcept Check

What are the 3 types of blood vessels?What are the 3 types of blood vessels?– Arteries, veins, capillariesArteries, veins, capillaries

Describe the flow of blood through the Describe the flow of blood through the heart starting w/ the body.heart starting w/ the body.– Body, (SVC, IVC, CS), R Atrium, Tricuspid Body, (SVC, IVC, CS), R Atrium, Tricuspid

Valve, Chordae Tendinae, R Ventricle, Valve, Chordae Tendinae, R Ventricle, Pulmonary SLV, Pulmonary Trunck, Pulmonary SLV, Pulmonary Trunck, Pulmonary Arteries, Lungs, Pulmonary Veins, Pulmonary Arteries, Lungs, Pulmonary Veins, L Atrium, Bicuspid Valve, Chordae Tendinae, L Atrium, Bicuspid Valve, Chordae Tendinae, L Ventricle, Aortic SLV, Aorta, Body L Ventricle, Aortic SLV, Aorta, Body

Disorders Disorders

IschemiaIschemia —faulty circulation weakens —faulty circulation weakens cells due to lack of oxygen, but the cells due to lack of oxygen, but the cells don’t diecells don’t die

Angina PectorisAngina Pectoris —chest pain resulting —chest pain resulting from ischemia; also from stress, over from ischemia; also from stress, over exertion, high blood pressure, or exertion, high blood pressure, or narrow arteriesnarrow arteries

Disorders Disorders

Myocardial InfarctionMyocardial Infarction (MI) —heart attack (MI) —heart attack– Infarction is the death of an area due to Infarction is the death of an area due to

interrupted blood supply; usually from a clotinterrupted blood supply; usually from a clot

– Tissue beyond the clot will die and become Tissue beyond the clot will die and become scar tissuescar tissue

– Location of the infarction area is key to how Location of the infarction area is key to how serious it isserious it is

Conduction System of the Conduction System of the HeartHeart

This is an intrinsic regulating systemThis is an intrinsic regulating system

It does not need a stimulus from the It does not need a stimulus from the nervous systemnervous system

All cardiac muscle is capable of self-All cardiac muscle is capable of self-excitationexcitation

Cardiac muscle generates its own Cardiac muscle generates its own action potentialaction potential

Sinoatrial (SA) NodeSinoatrial (SA) Node Located in the right atrial wall just below the Located in the right atrial wall just below the

superior vena cavasuperior vena cava

Known as theKnown as the pacemakerpacemaker of the heart of the heart– Rate of self-excitation is faster than all other heart Rate of self-excitation is faster than all other heart

fibersfibers

– Its impulses are spread to all the other areas thus Its impulses are spread to all the other areas thus setting the rhythm of the heartsetting the rhythm of the heart

– Both atria will contract at the same timeBoth atria will contract at the same time

– This will then depolarize the AV node (ventricles This will then depolarize the AV node (ventricles contract)contract)

Atrioventricular (AV) NodeAtrioventricular (AV) Node Located in the interatrial Located in the interatrial

septumseptum

Last part of atria to Last part of atria to depolarizedepolarize

This impulse will This impulse will depolarize fibers in the depolarize fibers in the interventricular septuminterventricular septum— — bundle of Hisbundle of His

This is the only electrical This is the only electrical connection between the connection between the atria and ventriclesatria and ventricles

Atrioventricular (AV) NodeAtrioventricular (AV) Node

The impulse passes toward the apex The impulse passes toward the apex through through left and right bundle left and right bundle branchesbranches to the ventricles to the ventricles

The actual contraction of the The actual contraction of the ventricles is done by the ventricles is done by the Purkinje Purkinje fibersfibers

Conducting System of Conducting System of HeartHeart

Electrocardiogram (ECG)Electrocardiogram (ECG)

A record of the A record of the electrical changes electrical changes that accompany that accompany the heartbeat.the heartbeat.

ElectrocardiogramElectrocardiogram Action potentials Action potentials

through myocardium through myocardium during cardiac cycle during cardiac cycle produces electric produces electric currents than can be currents than can be measured measured

PatternPattern– P wave P wave

Atria depolarizationAtria depolarization

– QRS complexQRS complex Ventricle depolarizationVentricle depolarization Atria repolarizationAtria repolarization

– T wave:T wave: Ventricle repolarizationVentricle repolarization

Cardiac ArrhythmiasCardiac Arrhythmias

TachycardiaTachycardia: Heart rate in excess of : Heart rate in excess of 100bpm100bpm

BradycardiaBradycardia: Heart rate less than 60 : Heart rate less than 60 bpmbpm

Sinus arrhythmiaSinus arrhythmia: Heart rate varies 5% : Heart rate varies 5% during respiratory cycle and up to 30% during respiratory cycle and up to 30% during deep respirationduring deep respiration

Premature atrial contractionsPremature atrial contractions: : Occasional shortened intervals Occasional shortened intervals between one contraction and between one contraction and succeeding, frequently occurs in succeeding, frequently occurs in healthy peoplehealthy people

Alterations in Alterations in ElectrocardiogramElectrocardiogram

Cardiac CycleCardiac Cycle

Cardiac CycleCardiac Cycle Heart is two pumps that work together, Heart is two pumps that work together,

right and left halfright and left half

Repetitive contraction (Repetitive contraction (systolesystole) and ) and relaxation (relaxation (diastolediastole) of heart chambers) of heart chambers

Blood moves through circulatory system Blood moves through circulatory system from areas of higher to lower pressure.from areas of higher to lower pressure.– Contraction of heart produces the pressureContraction of heart produces the pressure

Concept CheckConcept Check Why does the SA node act as the pacemaker?Why does the SA node act as the pacemaker?

– Impulses are spread to other areas setting the Impulses are spread to other areas setting the rhythm of the heartrhythm of the heart

How does the heart contract without an How does the heart contract without an impulse from the brain?impulse from the brain?– Intrinsic regulation / Self-excitation / Cardiac Intrinsic regulation / Self-excitation / Cardiac

muscle generates own action potentialsmuscle generates own action potentials

What actually contracts the myocardium of What actually contracts the myocardium of the ventricles?the ventricles?– Purkinje fibersPurkinje fibers

What is an infarct?What is an infarct?– Death of an area due to interrupted blood supply; Death of an area due to interrupted blood supply;

usually a clotusually a clot

Concept CheckConcept Check What does an EKG measure?What does an EKG measure?

– Electrical changes in the heart that accompany Electrical changes in the heart that accompany heart beatheart beat

Why is QRS bigger than P?Why is QRS bigger than P?– QRS = contraction of ventriclesQRS = contraction of ventricles– P = contraction of atriaP = contraction of atria

What is a fibrillation or arrhythmia?What is a fibrillation or arrhythmia?– Fibrillation = heart’s electrical activity has become Fibrillation = heart’s electrical activity has become

disordered; contraction rapid, unsynchronized; disordered; contraction rapid, unsynchronized; flutter rather than beat; heart pumps little or no flutter rather than beat; heart pumps little or no bloodblood

Heart RateHeart Rate

Cardiac OutputCardiac Output —amount of blood —amount of blood ejected from the left ventricle into the ejected from the left ventricle into the aorta per minuteaorta per minute

Stroke volumeStroke volume —amount of blood —amount of blood ejected from the left ventricle per ejected from the left ventricle per contractioncontraction

Factors Affecting Heart RateFactors Affecting Heart Rate Autonomic controlAutonomic control —baroreceptors—neurons —baroreceptors—neurons

sensitive to blood pressure changessensitive to blood pressure changes

ChemicalsChemicals —too much or too little K —too much or too little K++, Na, Na++, or , or CaCa++ either increases or decreases heart rate; either increases or decreases heart rate; oxygen demandsoxygen demands

TemperatureTemperature —increase temperature, increase —increase temperature, increase heart rate; lower temperature, decrease heart heart rate; lower temperature, decrease heart raterate

EmotionsEmotions —fear, anxiety, anger all increase —fear, anxiety, anger all increase heart rate while depression and grief lower heart rate while depression and grief lower heart rateheart rate

Sex and ageSex and age —faster in females; fastest at —faster in females; fastest at birth but slows as one gets olderbirth but slows as one gets older

More Disorders More Disorders Arteriosclerosis - thickening of the walls of the Arteriosclerosis - thickening of the walls of the

arteries and loss of elasticityarteries and loss of elasticity

Atherosclerosis - Deposition of plaque on wallsAtherosclerosis - Deposition of plaque on walls

Congenital defects—a defect that exists at birthCongenital defects—a defect that exists at birth– Interventricular septal defect—hole in septumInterventricular septal defect—hole in septum– Valvular stenosis—narrowing of a valveValvular stenosis—narrowing of a valve– Arrthymia—any irregularity in heart rhythmArrthymia—any irregularity in heart rhythm

Effects of Aging on the HeartEffects of Aging on the Heart

Gradual changes in heart function, minor Gradual changes in heart function, minor under resting condition, more significant under resting condition, more significant during exerciseduring exercise

Hypertrophy of left ventricleHypertrophy of left ventricle Maximum heart rate decreasesMaximum heart rate decreases Increased tendency for valves to function Increased tendency for valves to function

abnormally and arrhythmias to occurabnormally and arrhythmias to occur Increased oxygen consumption required Increased oxygen consumption required

to pump same amount of bloodto pump same amount of blood

Heart SoundsHeart Sounds First heart sound or “lubb”First heart sound or “lubb”

– Atrioventricular valves and surrounding fluid Atrioventricular valves and surrounding fluid vibrations as valves close at beginning of vibrations as valves close at beginning of ventricular systoleventricular systole

Second heart sound or “dupp”Second heart sound or “dupp”– Results from closure of aortic and pulmonary Results from closure of aortic and pulmonary

semilunar valves at beginning of ventricular semilunar valves at beginning of ventricular diastole, lasts longerdiastole, lasts longer

Third heart sound Third heart sound (occasional)(occasional)– Caused by turbulent blood flow into ventricles Caused by turbulent blood flow into ventricles

and detected near end of first one-third of and detected near end of first one-third of diastolediastole

Blood PressureBlood Pressure

Measure of force exerted by blood Measure of force exerted by blood against the wallagainst the wall

Blood moves through vessels because Blood moves through vessels because of blood pressureof blood pressure

Measured by listening for Korotkoff Measured by listening for Korotkoff sounds produced by turbulent flow in sounds produced by turbulent flow in arteries as pressure released from arteries as pressure released from blood pressure cuffblood pressure cuff

Pulse PressurePulse Pressure Difference between Difference between

systolic (contraction systolic (contraction of ventricles) and of ventricles) and diastolic (relaxation of diastolic (relaxation of ventricles)ventricles) pressures pressures

Increases when stroke Increases when stroke volume increases or volume increases or vascular compliance vascular compliance decreasesdecreases

Pulse pressure can be Pulse pressure can be used to take a pulse used to take a pulse to determine to determine heart heart rate and rhythmicityrate and rhythmicity

Concept CheckConcept Check

What types of things would increase What types of things would increase your heart rate? Decrease?your heart rate? Decrease?

What is a congenital disorder? Describe What is a congenital disorder? Describe the problems with interventricular septal the problems with interventricular septal defect.defect.

What is the difference between systole What is the difference between systole and diastole if they both measure on the and diastole if they both measure on the arteries?arteries?

What causes the heart sounds?What causes the heart sounds?