The Cardiovascular System: The Heart: Part A Cardiovascular System.

The Cardiovascular System: The Heart: Part A

Cardiovascular System

The Pulmonary and Systemic CircuitsHeart is transport system; two

side-by-side pumps Pulmonary Circuit

Right side receives oxygen-poor blood from tissues

Pumps to lungs to get rid of CO2, pick up O2

Systemic Circuit Left side receives oxygenated blood from lungs Pumps to body tissues

© 2013 Pearson Education, Inc.

The Pulmonary and Systemic CircuitsReceiving chambers of heart:

Right atrium Receives blood returning from systemic circuit

Left atrium Receives blood returning from pulmonary circuit


The Pulmonary and Systemic CircuitsPumping chambers of heart:

Right ventricle Pumps blood through pulmonary circuit

Left ventricle Pumps blood through systemic circuit


Figure 18.1 The systemic and pulmonary circuits.


Capillary beds oflungs where gasexchange occurs

Pulmonary CircuitPulmonaryarteries Pulmonary veins

Aorta and branchesVenaecavae

Leftatrium

LeftventricleRight

atrium

Rightventricle

Heart

Systemic Circuit

Oxygen-rich,CO2-poor bloodOxygen-poor,CO2-rich blood

Capillary beds of allbody tissues wheregas exchange occurs

Heart AnatomyApproximately size of fist

Location: In mediastinum between second rib and fifth

intercostal space Two-thirds of heart to left of midsternal line


Heart AnatomyBase (posterior surface) leans toward right shoulder

Apex points toward left hip

Apical impulse palpated between fifth and sixth ribs, just below left nipple


Figure 18.2a Location of the heart in the mediastinum.


Midsternal line

2nd rib

DiaphragmSternum

Location ofapical impulse

Figure 18.2b Location of the heart in the mediastinum.


Mediastinum

HeartLeft lung

Body of T7 vertebra

Posterior


Superiorvena cava

Pulmonarytrunk

Diaphragm

Aorta

Parietal pleura(cut)

Left lung

Pericardium (cut)

Apex of heart

Coverings of the Heart: PericardiumDouble-walled sac

Superficial fibrous pericardium Protects, anchors to surrounding structures, and

prevents overfilling


PericardiumDeep two-layered serous pericardium

Parietal layer lines internal surface of fibrous pericardium

Visceral layer (epicardium) on external surface of heart

Two layers separated by fluid-filled pericardial cavity (decreases friction)



Pericardium

Myocardium

Pulmonarytrunk Fibrous pericardium

Parietal layer of serous pericardium

Pericardial cavity

Epicardium (viscerallayer of serouspericardium)

Myocardium

Endocardium

Heart chamber

Heart wall

Homeostatic ImbalancePericarditis

Inflammation of pericardium Roughens membrane surfaces pericardial

friction rub (creaking sound) heard with stethoscope

Cardiac tamponade Excess fluid sometimes compresses heart

limited pumping ability


Layers of the Heart WallThree layers of heart wall:

Epicardium Myocardium Endocardium

Epicardium Visceral layer of serous pericardium


Layers of the Heart WallMyocardium

Spiral bundles of contractile cardiac muscle cells Cardiac skeleton: crisscrossing, interlacing layer of

connective tissue Anchors cardiac muscle fibers Supports great vessels and valves Limits spread of action potentials to specific

paths


Layers of the Heart WallEndocardium continuous with endothelial

lining of blood vessels Lines heart chambers; covers cardiac skeleton of

valves



Pericardium

Myocardium

Pulmonarytrunk Fibrous pericardium

Parietal layer of serous pericardium

Pericardial cavity

Epicardium (viscerallayer of serouspericardium)

Myocardium

Endocardium

Heart chamber

Heart wall


Cardiacmusclebundles

Chambers Four chambers:

Two superior atria Two inferior ventricles

Interatrial septum – separates atria Fossa ovalis – remnant of foramen ovale of fetal

heart

Interventricular septum – separates ventricles



Superior vena cava

Right pulmonary artery

Pulmonary trunkRight atrium

Right pulmonary veins

Fossa ovalisPectinate muscles

Tricuspid valve

Right ventricleChordae tendineaeTrabeculae carneae

Inferior vena cava

Aorta

Left pulmonary artery

Left atrium

Left pulmonary veins

Mitral (bicuspid) valve

Aortic valve

Pulmonary valve

Left ventriclePapillary muscleInterventricular septumEpicardiumMyocardiumEndocardium

Frontal section

Chambers and Associated Great VesselsCoronary sulcus (atrioventricular groove)

Encircles junction of atria and ventricles

Anterior interventricular sulcus Anterior position of interventricular septum

Posterior interventricular sulcus Landmark on posteroinferior surface


Atria: The Receiving ChambersAuricles

Appendages that increase atrial volume

Right atrium Pectinate muscles Posterior and anterior regions separated by crista

terminalis

Left atrium Pectinate muscles only in auricles


Atria: The Receiving Chambers

Small, thin-walled

Contribute little to propulsion of blood

Three veins empty into right atrium: Superior vena cava, inferior vena cava,

coronary sinus

Four pulmonary veins empty into left atrium


Ventricles: The Discharging Chambers

Most of the volume of heart

Right ventricle - most of anterior surface

Left ventricle – posteroinferior surface

Trabeculae carneae – irregular ridges of muscle on walls

Papillary muscles – anchor chordae tendineae


Ventricles: The Discharging Chambers Thicker walls than atria

Actual pumps of heart

Right ventricle Pumps blood into pulmonary trunk

Left ventricle Pumps blood into aorta (largest artery in body)



Brachiocephalic trunk

Superior vena cava

Right pulmonary artery

Ascending aortaPulmonary trunk

Right pulmonary veins

Right atriumRight coronary artery(in coronary sulcus)Anterior cardiac veinRight ventricle

Right marginal artery

Small cardiac vein

Inferior vena cava

Left common carotid artery

Left subclavian arteryAortic archLigamentum arteriosumLeft pulmonary artery


Auricle ofleft atrium

Circumflex artery

Left coronary artery(in coronary sulcus)

Left ventricle

Great cardiac veinAnterior interventricularartery (in anteriorinterventricular sulcus)

ApexAnterior view


Aortic arch (fat covered)

Pulmonary trunk

Auricle of right atrium

Auricle of left atrium

Anterior interventricularartery

Right ventricle

Apex of heart (left ventricle)

Anterior aspect (pericardium removed)


Photograph; view similar to (e)

Superior vena cava Ascending aorta (cut open)

Pulmonary trunk

Aortic valve

Pulmonary valve

Interventricularseptum (cut)Left ventricle

Papillary muscles

Right ventricle anteriorwall (retracted)

Trabeculae carneae

Opening to rightatrium

Chordae tendineae

Right ventricle

Heart Valves

Ensure unidirectional blood flow through heart

Open and close in response to pressure changes

Two atrioventricular (AV) valvesPrevent backflow into atria when ventricles

contractTricuspid valve (right AV valve)Mitral valve (left AV valve, bicuspid valve)Chordae tendineae anchor cusps to papillary

muscles Hold valve flaps in closed position


Figure 18.7 The atrioventricular (AV) valves.


1

2

3

Blood returning to the heart fillsatria, pressing against the AV valves.The increased pressure forces AVvalves open.

As ventricles fill, AV valve flapshang limply into ventricles.

1

2 3

Atria contract, forcing additionalblood into ventricles.

Ventricles contract, forcingblood against AV valve cusps.

AV valves close.

Papillary muscles contract andchordae tendineae tighten,preventing valve flaps from evertinginto atria.

AV valves open; atrial pressure greater than ventricular pressure

AV valves closed; atrial pressure less than ventricular pressure

Direction ofblood flow

Cusp ofatrioventricularvalve (open)

Atrium

Chordaetendineae

Papillarymuscle

Atrium

Cusps ofatrioventricularvalve (closed)

Blood inventricle

Ventricle

Heart Valves

Two semilunar (SL) valves Prevent backflow into ventricles when ventricles

relax Open and close in response to pressure changes Aortic semilunar valve Pulmonary semilunar valve


Figure 18.8 The semilunar (SL) valves.


As ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open.

As ventricles relax and intraventricular pressure falls, blood flows back from arteries, filling the cusps of semilunar valves and forcing them to close.

Aorta

Pulmonarytrunk

Semilunar valves open

Semilunar valves closed

Figure 18.6a Heart valves.


Pulmonary valveAortic valve

Area of cutaway

Mitral valveTricuspid valve

Myocardium

Mitral(left atrioventricular)valveTricuspid(right atrioventricular) valveAortic valve

Pulmonary valve

Anterior

Cardiacskeleton

Figure 18.6b Heart valves.


Pulmonary valveAortic valve

Area of cutaway

Mitral valveTricuspid valve

Myocardium

Mitral(left atrioventricular)valveTricuspid(right atrioventricular) valveAortic valve

Pulmonary valve

Figure 18.6c Heart valves.


Pulmonary valve

Aortic valve

Area of cutaway

Mitral valve

Tricuspid valve

Chordae tendineae attached to tricuspid valve flap

Papillary muscle

Figure 18.6d Heart valves.


Pulmonary valve

Aortic valve

Area of cutaway

Mitral valve

Tricuspid valve

Opening of inferiorvena cava

Tricuspid valve

Myocardium of right ventricle

Papillary muscles

Mitral valveChordae tendineae

Interventricular septum

Myocardium of left ventricle

Homeostatic ImbalanceTwo conditions severely weaken heart:

Incompetent valve Blood backflows so heart repumps same blood

over and over Valvular stenosis

Stiff flaps – constrict opening heart must exert more force to pump blood

Valve replaced with mechanical, animal, or cadaver valve


Pathway of Blood Through the HeartPulmonary circuit

Right atrium tricuspid valve right ventricle Right ventricle pulmonary semilunar valve

pulmonary trunk pulmonary arteries lungs Lungs pulmonary veins left atrium


Pathway of Blood Through the HeartSystemic circuit

Left atrium mitral valve left ventricle Left ventricle aortic semilunar valve aorta Aorta systemic circulation


Both sides of the heart pump at the same time, but let’s follow one spurt of blood all the way through the system. Oxygen-rich blood

Superior vena cava (SVC)Inferior vena cava (IVC)

Coronary sinus

Rightatrium

Tricuspidvalve

PulmonarySemilunar

valveRightventricle

Pulmonarytrunk

SVC

IVC

Coronarysinus

Rightatrium

Tricuspidvalve

Rightventricle

Pulmonaryarteries

Pulmonarytrunk

Pulmonarysemilunarvalve

To heartOxygen-poor blood returns from the body tissues back to the heart.

Oxygen-poor blood is carriedin two pulmonary arteries tothe lungs (pulmonary circuit)to be oxygenated.

To lungs

Systemiccapillaries

Pulmonarycapillaries

To bodyOxygen-rich blood is delivered to the body tissues (systemic circuit).

Oxygen-rich blood returns to the heart via the four pulmonary veins.

To heart

Pulmonaryveins

Leftatrium

MitralvalveLeftventricle

Aorta

Aorticsemilunarvalve

AorticSemilunar

valveMitralvalve

AortaLeft

ventricleLeft

atrium

Four pulmonary

veins

Oxygen-poor bloodSlide 1

Figure 18.9 The heart is a double pump, each side supplying its own circuit.


Oxygen-poor blood

Oxygen-rich blood


Coronary sinus

SVC

IVC

Coronarysinus

Slide 2



Slide 3

Oxygen-poor blood

Oxygen-rich blood


Coronary sinus

Rightatrium

SVC

IVC

Coronarysinus

Rightatrium



Slide 4

Oxygen-poor blood

Oxygen-rich blood


Coronary sinus

Rightatrium

Tricuspidvalve Right

ventricle

SVC

IVC

Coronarysinus

Rightatrium

Tricuspidvalve

Rightventricle



Slide 5

Oxygen-poor blood

Oxygen-rich blood


Coronary sinus

Rightatrium

Tricuspidvalve

PulmonarySemilunar

valveRightventricle

Pulmonarytrunk

SVC

IVC

Coronarysinus

Rightatrium

Tricuspidvalve

Rightventricle

Pulmonaryarteries

Pulmonarytrunk




Slide 6Oxygen-poor blood

Oxygen-rich blood


Coronary sinus

Rightatrium

Tricuspidvalve

PulmonarySemilunar

valveRightventricle

Pulmonarytrunk

SVC

IVC

Coronarysinus

Rightatrium

Tricuspidvalve

Rightventricle

Pulmonaryarteries

Pulmonarytrunk


Oxygen-poor blood is carriedin two pulmonary arteries to the lungs (pulmonary circuit)to be oxygenated.

To lungs



Oxygen-poor bloodOxygen-rich bloodPulmonary

veins

Four pulmonary

veins

Slide 7



Slide 8

Pulmonaryveins

Leftatrium

Leftatrium

Four pulmonary

veins

Blood Flow Through the Heart

Oxygen-poor blood

Oxygen-rich blood

Rightventricle



Slide 9

Oxygen-poor blood

Oxygen-rich blood

Pulmonaryveins

Leftatrium


MitralvalveLeft

ventricleLeft

atrium

Four pulmonary

veins



Slide 10

Oxygen-poor blood

Oxygen-rich bloodRight

ventricle

Pulmonaryveins

Leftatrium


Aorta


AorticSemilunar

valveMitralvalve

AortaLeft

ventricleLeft

atrium

Four pulmonary

veins



Slide 11

Blood Flow Through the Heart

Systemiccapillaries

To body

Oxygen-rich blood is delivered to the body tissues (systemic circuit).

Pulmonaryveins

Leftatrium


Aorta


AorticSemilunar

valveMitralvalveAorta

Leftventricle

Leftatrium

Four pulmonary

veins

Oxygen-poor blood

Oxygen-rich blood



Slide 12Both sides of the heart pump at the same time, but let’s follow one spurt of blood all the way through the system. Oxygen-rich blood


Coronary sinus

Rightatrium

Tricuspidvalve

PulmonarySemilunar

valveRightventricle

Pulmonarytrunk

SVC

IVC

Coronarysinus

Rightatrium

Tricuspidvalve

Rightventricle

Pulmonaryarteries

Pulmonarytrunk


To heartOxygen-poor blood returns from the body tissues back to the heart.

Oxygen-poor blood is carriedin two pulmonary arteries tothe lungs (pulmonary circuit)to be oxygenated.

To lungs

Systemiccapillaries


To bodyOxygen-rich blood is delivered to the body tissues (systemic circuit).

Oxygen-rich blood returns to the heart via the four pulmonary veins.

To heart

Pulmonaryveins

Leftatrium


Aorta


AorticSemilunar

valveMitralvalve

AortaLeft

ventricleLeft

atrium

Four pulmonary

veins

Oxygen-poor blood

Pathway of Blood Through the HeartEqual volumes of blood pumped to pulmonary

and systemic circuits

Pulmonary circuit short, low-pressure circulation

Systemic circuit long, high-friction circulation

Anatomy of ventricles reflects differences Left ventricle walls 3X thicker than right

Pumps with greater pressure


Figure 18.10 Anatomical differences between the right and left ventricles.


Rightventricle

Interventricularseptum

Leftventricle

Coronary CirculationFunctional blood supply to heart muscle itself

Delivered when heart relaxed Left ventricle receives most blood supply

Arterial supply varies among individuals

Contains many anastomoses (junctions) Provide additional routes for blood delivery Cannot compensate for coronary artery occlusion


Coronary Circulation: ArteriesArteries arise from base of aorta

Left coronary artery branches anterior interventricular artery and circumflex arterySupplies interventricular septum, anterior

ventricular walls, left atrium, and posterior wall of left ventricle

Right coronary artery branches right marginal artery and posterior interventricular arterySupplies right atrium and most of right ventricle



Aorta

Superiorvena cava

Anastomosis(junction ofvessels)

Rightatrium

Rightcoronaryartery

Rightventricle

Rightmarginalartery

Posteriorinterventricularartery

Anterior interventricularartery

Leftventricle

Circumflexartery

Leftcoronaryartery

Left atrium

Pulmonarytrunk

The major coronary arteries

Coronary Circulation: VeinsCardiac veins collect blood from capillary

beds

Coronary sinus empties into right atrium; formed by merging cardiac veinsGreat cardiac vein of anterior interventricular

sulcusMiddle cardiac vein in posterior interventricular

sulcusSmall cardiac vein from inferior margin

Several anterior cardiac veins empty directly into right atrium anteriorly



Superiorvena cava

Anteriorcardiacveins

Smallcardiac vein Middle cardiac vein

Coronarysinus

Greatcardiacvein

The major cardiac veins


Aorta

Left pulmonary artery


Auricle of left atriumLeft atrium

Great cardiac vein

Posterior vein ofleft ventricleLeft ventricle

Apex

Superior vena cava

Right pulmonary arteryRight pulmonary veins

Right atrium

Inferior vena cava

Coronary sinusRight coronary artery(in coronary sulcus)Posterior interventricularartery (in posteriorinterventricular sulcus)Middle cardiac veinRight ventricle

Posterior surface view

Homeostatic ImbalancesAngina pectoris

Thoracic pain caused by fleeting deficiency in blood delivery to myocardium

Cells weakened

Myocardial infarction (heart attack) Prolonged coronary blockage Areas of cell death repaired with noncontractile

scar tissue


Figure 18.12a Microscopic anatomy of cardiac muscle.


NucleusIntercalated

discsCardiac

muscle cell Gap junctions Desmosomes

Microscopic Anatomy of Cardiac MuscleIntercalated discs - junctions between cells -

anchor cardiac cells Desmosomes prevent cells from separating during

contraction Gap junctions allow ions to pass from cell to cell;

electrically couple adjacent cells Allows heart to be functional syncytium

Behaves as single coordinated unit


Figure 18.12b Microscopic anatomy of cardiac muscle.


Cardiac muscle cellIntercalated disc

Mitochondrion Nucleus

MitochondrionT tubuleSarcoplasmicreticulum Z disc

I band A band I band

NucleusSarcolemma

The Cardiovascular System: The Heart: Part A Cardiovascular System.

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Transcript of The Cardiovascular System: The Heart: Part A Cardiovascular System.