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© 2012 Pearson Education, Inc.

PowerPoint ® Lecture Presentations prepared by

Jason LaPres

Lone Star College—North Harris

20The Heart

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An Introduction to the Cardiovascular System

• The Pulmonary Circuit

• Carries blood to and from gas exchange surfaces of

lungs

• The Systemic Circuit

• Carries blood to and from the body

• Blood alternates between pulmonary circuit and

systemic circuit

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• Three Types of Blood Vessels

1. Arteries

• Carry blood away from heart

2. Veins

• Carry blood to heart

3. Capillaries

• etwor!s between arteries and veins

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• Capillaries

• Also called exchange vessels

• "xchange materials between blood and tissues

• #aterials include dissolved gases$ nutrients$ waste

products

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Figure 20-1 An vervie! o" the Car#iovascular System

P$%&'A() C*(C$*+ S)S+,&*C C*(C$*+

Pulmonary arteries

Pulmonary veins Systemic veins

Systemic arteries

Capillariesin lungs

(ightatrium

(ightventricle

Capillariesin trun

an# lo!er

lims

Capillariesin hea#/nec/ upper lims

%e"tatrium

%e"tventricle

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•

%our Chambers of the &eart1. (ight atrium

• Collects blood from systemic circuit

2. (ight ventricle• 'umps blood to pulmonary circuit

3. %e"t atrium

•

Collects blood from pulmonary circuit. %e"t ventricle

• 'umps blood to systemic circuit

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()*+ Anatomy of the &eart

• The &eart

• ,reat veins and arteries at the base

• 'ointed tip is apex

• Surrounded by pericardial sac

• Sits between two pleural cavities in the me#iastinum

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Figure 20-2a +he %ocation o" the eart in the +horacic Cavity

Trachea

First rib (cut)

ase o" heart

Right lung

Diaphragm

Thyroid gland

Left lung

Apex o" heart

Parietal pericar#iumcut4

An anterior vie! o" the chest/ sho!ing the position o" the heart an#ma5or loo# vessels relative to the ris/ lungs/ an# #iaphragm.

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• The Pericar#ium

• -ouble lining of the pericardial cavity

• Visceral pericar#ium

• Inner layer of pericardium

• Parietal pericar#ium

• .uter layer

• %orms inner layer of pericar#ial sac

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• The 'ericardium

• 'ericardial cavity

• Is between parietal and visceral layers

• Contains pericar#ial "lui#

• 'ericardial sac

•

%ibrous tissue

• Surrounds and stabili/es heart

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Figure 20-2 +he %ocation o" the eart in the +horacic Cavity

(ight ventricle

Aorticarch

Posterior me#iastinum

Aorta arch segment remove#4

%e"t pulmonary artery

%e"t pulmonary vein

Pulmonary trun

%e"t ventricle

,picar#ium

Pericar#ial sacAnterior me#iastinum

Pericar#ial cavity

(ight atrium

%e"t atrium

(ight pulmonary artery

(ight pulmonary vein

Superior vena cava

Esophagus

Right pleural cavity

Bronchus of lung

Right lung Left

lung

Left pleural cavity

A superior vie! o" the organs in the me#iastinum6 portions o" the lungs haveeen remove# to reveal loo# vessels an# air!ays. +he heart is situate# inthe anterior part o" the me#iastinum/ imme#iately posterior to the sternum.

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Figure 20-2c +he %ocation o" the eart in the +horacic Cavity

7rist correspon#sto ase o" heart4

*nner !all correspon#sto epicar#ium4

Air space correspon#sto pericar#ial cavity4

uter !all correspon#sto parietal pericar#ium4

alloon

Cut e#ge o" parietal pericar#ium

Firous tissue o" pericar#ial sac

Parietal pericar#iumAreolar tissue

&esothelium

Cut e#ge o" epicar#ium

Apex o" heart

ase o" heart

Firousattachment

to #iaphragm

+he relationship et!een the heart an# the pericar#ial cavity6 compare !ith the "ist-an#-alloon example.

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• Superficial Anatomy of the &eart

• Atria

• Thin*walled

• "xpandable outer auricle 0atrial appendage1

Fi 20 3 +h S "i i l A t " th t

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Figure 20-3a +he Super"icial Anatomy o" the eart

%e"t commoncaroti# artery

rachiocephalictrun

Ascen#ingaorta

Superior vena cava

Auricle

o" rightatrium

Fat an#vessels incoronary

sulcus

%e"t suclavian artery

Arch o" aorta

%igamentumarteriosum

8escen#ingaorta

%e"t pulmonaryartery

Pulmonarytrun

Auricle o" le"t atrium

Fat an# vesselsin anterior interventricular sulcus

%,F+V,'+(*C%,

(*9+V,'+(*C%,

(*9+A+(*$&

&a5or anatomical "eatures on the anterior sur"ace.


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Figure 20-3a +he Super"icial Anatomy o" the eart

Ascen#ingaorta

Parietalpericar#ium

Superior vena cava

Auricle o" right atrium

(*9+ A+(*$&

(ight coronaryartery

Coronary sulcus

(*9+ V,'+(*C%,

&arginal rancho" right coronary artery

Auricle o" le"t atrium

Pulmonarytrun

Firouspericar#ium

Parietal pericar#ium"use# to #iaphragm

Anterior interventricular

sulcus

%,F+V,'+(*C%,

&a5or anatomical "eatures on the anterior sur"ace.


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Figure 20-3 +he Super"icial Anatomy o" the eartArch o" aorta

(ight pulmonaryartery

Superior

vena cava

(ightpulmonaryveins superior an# in"erior4

*n"erior vena cava

Fat an# vessels in posterior interventricular sulcus

(*9+V,'+(*C%,

%,F+V,'+(*C%,

(*9+

A+(*$&

%,F+A+(*$&

%e"t pulmonary artery

%e"t pulmonary veins

Fat an# vessels incoronary sulcus

Coronarysinus

&a5or lan#mars on the posterior sur"ace. Coronaryarteries !hich supply the heart itsel"4 are sho!n in

re#6 coronary veins are sho!n in lue.


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Figure 20-3c +he Super"icial Anatomy o" the eart

ase o" heart

Apex o" heart

(is

eart position relative to the ri cage.

1

2

3

:

;

<

=>

10

1

2

3

:

;

<

=

>

10

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• The &eart 2all

1. ,picar#ium

2. &yocar#ium

3. ,n#ocar#ium

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•

,picar#ium 0.uter 3ayer1• Visceral pericardium

• Covers the heart

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•

&yocar#ium 0#iddle 3ayer1• #uscular wall of the heart

• Concentric layers of cardiac muscle tissue

• Atrial myocardium wraps around great vessels

• Two divisions of ventricular myocardium

• ,n#ocar#ium 0Inner 3ayer1

• Simple s4uamous epithelium

Figure 20-a +he eart 7all

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Figure 20-a +he eart 7all

&esothelium

,n#ocar#ium

Areolar tissue

,n#othelium

&esothelium

8ense "irous layer

Parietal pericar#ium

Pericar#ial cavity

Areolar tissue

Areolar tissue

Connective tissues

Car#iac muscle cells

&yocar#iumcar#iac muscle tissue4

,picar#iumvisceral pericar#ium4

Figure 20- +he eart 7all

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Figure 20- +he eart 7all

Atrialmusculature

Car#iac muscle tissue

"orms concentric layersthat !rap aroun# the

atria or spiral !ithin the

!alls o" the ventricles.

Ventricular musculature

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• Cardiac #uscle Tissue

• *ntercalate# #iscs

• Interconnect car#iac muscle cells

• Secured by desmosomes

• 3in!ed by gap 5unctions

•

Convey force of contraction

• 'ropagate action potentials

Figure 20-:a Car#iac &uscle Cells

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Figure 20 :a Car#iac &uscle Cells

Car#iac muscle cells

'ucleus

Car#iac musclecell sectione#4

un#les o" myo"irils

Car#iac muscle cell

&itochon#ria

*ntercalate##isc sectione#4

*ntercalate# #iscs

Figure 20-: Car#iac &uscle Cells

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Figure 20 : Car#iac &uscle Cells

*ntercalate# #isc

9ap 5unction

pposing plasmamemranes

8esmosomes

Structure o" an intercalate# #isc

Figure 20-:c Car#iac &uscle Cells

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g

*ntercalate# #iscs

Car#iac muscle tissue

Car#iac muscle tissue %& :

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• Internal Anatomy and .rgani/ation

• *nteratrial septum separates atria

• *nterventricular septum separates ventricles

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• Internal Anatomy and .rgani/ation

• Atrioventricular AV4 valves

• Connect right atrium to right ventricle and left

atrium to left ventricle

• Are folds of fibrous tissue that extend into

openings between atria and ventricles

• 'ermit blood flow in one direction

• %rom atria to ventricles

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• The 6ight Atrium

• Superior vena cava

• 6eceives blood from head$ nec!$ upper limbs$ and chest

• *n"erior vena cava

• 6eceives blood from trun!$ viscera$ and lower limbs

• Coronary sinus

• Cardiac veins return blood to coronary sinus

• Coronary sinus opens into right atrium

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• The 6ight Atrium

• Foramen ovale

• Before birth$ is an opening through interatrial septum

• Connects the two atria

• Seals off at birth$ forming "ossa ovalis

Figure 20-;a +he Sectional Anatomy o" the eart%e"t common caroti# artery

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8escen#ing aorta

%e"t common caroti# artery

%e"t suclavian artery

%igamentum arteriosum

Pulmonary trun

Pulmonary valve

%e"t pulmonaryarteries

%e"t pulmonaryveins

*nteratrial septumAortic valve

Cusp o" le"t AVmitral4 valve

%,F+ V,'+(*C%,

*nterventricular septum

+raeculaecarneae

&o#erator an#

Aortic arch

%,F+A+(*$&

rachiocephalictrun

Superior vena cava

(ightpulmonary

arteries

Ascen#ing aorta

Fossa ovalis

pening o" coronary sinus

(*9+ A+(*$&

Pectinate muscles

Conus arteriosus

Cusp o" right AVtricuspi#4 valve

Chor#ae ten#ineae

Papillary muscles

(*9+ V,'+(*C%,

*n"erior vena cava

Figure 20-;c +he Sectional Anatomy o" the eart

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© 2012 Pearson Education, Inc.A "rontal section/ anterior vie!.

*n"erior vena cava

(*9+ V,'+(*C%,

Papillary muscles

Cusps o" right AVtricuspi#4 valve

Pectinate muscles

(*9+ A+(*$&

Fossa ovalis

Ascen#ing aorta

Cusp o" le"t AVicuspi#4 valve


%,F+ V,'+(*C%,

Chor#ae ten#ineae

%e"t coronary arteryranches re#4

an# great car#iacvein lue4Cusp o" aortic valve

Coronary sinus

+raeculae carneae

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• The 6ight Ventricle

• %ree edges attach to chor#ae ten#ineae from

papillary muscles of ventricle

•

'revent valve from opening bac!ward

• (ight atrioventricular AV4 valve

• Also called tricuspi# valve

• .pening from right atrium to right ventricle

• &as three cusps

• 'revents bac!flow

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• The 6ight Ventricle

• +raeculae carneae

• #uscular ridges on internal surface of right 0and left1

ventricle

• Includes moderator band

• 6idge contains part of conducting system

• Coordinates contractions of cardiac muscle cells

Figure 20-; +he Sectional Anatomy o" the eart

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+he papillary muscles an# chor#ae

ten#inae supporting the right AV

tricuspi#4 valve. +he photograph

!as taen "rom insi#e the right

ventricle/ looing to!ar# a light

shining "rom the right atrium.

Chor#ae ten#ineae

Papillary muscles

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• The 'ulmonary Circuit

• Conus arteriosus 0superior end of right ventricle1

leads to pulmonary trun

• 'ulmonary trun! divides into le"t and right

pulmonary arteries

• Blood flows from right ventricle to pulmonary trun!

through pulmonary valve

• 'ulmonary valve has three semilunar cusps

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• The 3eft Atrium

• Blood gathers into le"t and right pulmonary veins

• 'ulmonary veins deliver to left atrium

• Blood from left atrium passes to left ventricle through

le"t atrioventricular AV4 valve

•

A two*cusped icuspi# valve or mitral valve

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• The 3eft Ventricle

• &olds same volume as right ventricle

• Is larger7 muscle is thic!er and more powerful

• Similar internally to right ventricle but does not have

moderator band

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• The 3eft Ventricle

• Systemic circulation

• Blood leaves left ventricle through aortic valve

into ascen#ing aorta• Ascending aorta turns 0aortic arch1 and becomes

#escen#ing aorta

Figure 20-;c +he Sectional Anatomy o" the eart

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© 2012 Pearson Education, Inc.A "rontal section/ anterior vie!.

*n"erior vena cava

(*9+ V,'+(*C%,

Papillary muscles

Cusps o" right AVtricuspi#4 valve

Pectinate muscles

(*9+ A+(*$&

Fossa ovalis

Ascen#ing aorta

Cusp o" le"t AVicuspi#4 valve


%,F+ V,'+(*C%,

Chor#ae ten#ineae

%e"t coronary arteryranches re#4

an# great car#iacvein lue4Cusp o" aortic valve

Coronary sinus

+raeculae carneae

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• Structural -ifferences between the 3eft and

6ight Ventricles

• 6ight ventricle wall is thinner$ develops less pressure

than left ventricle

• 6ight ventricle is pouch*shaped$ left ventricle is round

AI#ATI. The &eart8 &eart Anatomy

Figure 20-

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%e"tventricle

(ightventricle

Posterior interventricular sulcus

Fat in anterior interventricular sulcus

A #iagrammatic sectional vie! through the heart/

sho!ing the relative thicnesses o" the t!o ventricles.

'otice the pouchlie shape o" the right ventricle an#

the greater thicness o" the le"t ventricle.

Figure 20-

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8ilate# Contracte#

8iagrammatic vie!s o" the ventricles 5ust

e"ore a contraction #ilate#4 an# 5ust a"ter a

contraction contracte#4.

%e"tventricle

(ightventricle

() + A t f th & t

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• The &eart Valves

• Two pairs of one*way valves prevent bac!flow

during contraction

• Atrioventricular AV4 valves

• Between atria and ventricles

• Blood pressure closes valve cusps during ventricular

contraction

• 'apillary muscles tense chordae tendineae to prevent

valves from swinging into atria

() + A t f th & t

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• The &eart Valves

• Semilunar valves

• 'ulmonary and aortic tricuspid valves

• 'revent bac!flow from pulmonary trun! and aorta

into ventricles

•

&ave no muscular support

• Three cusps support li!e tripod

Figure 20-=a Valves o" the eart

+ S ti S i Vi

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( e l a x e # v e

n t r i c l e s

(ight AV

tricuspi#4

valve open4

+ransverse Sections/ Superior Vie!/Atria an# Vessels (emove#

PS+,(*(

(*9+V,'+(*C%,

Car#iac

seleton

%e"t AV icuspi#4

valve open4

%,F+V,'+(*C%,

Aortic valveclose#4

Pulmonaryvalve close#4A'+,(*(

Aortic valve close#

7hen the ventricles are relaxe#/ the AV valves

are open an# the semilunar valves are close#.

+he chor#ae ten#ineae are loose/ an# the

papillary muscles are relaxe#.

Figure 20-=a Valves o" the eart

F t l S ti th h % "t At i # V t i l

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Aortic valveclose#4

%,F+A+(*$&

%e"t AV icuspi#4valve open4

Chor#aeten#ineae loose4

Papillary musclesrelaxe#4

%,F+ V,'+(*C%,relaxe# an# "illing!ith loo#4

Pulmonaryveins

Frontal Sections through %e"t Atrium an# Ventricle

( e l a x e # v e

n t r i c l e s

Figure 20-= Valves o" the eart

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C o n t r a c t i n g v e n t r i c l e s

Aortic valve open

(*9+V,'+(*C%,

(ight AVtricuspi#4 valve

close#4

Car#iacseleton

%e"t AVicuspi#4 valve

close#4%,F+V,'+(*C%,

Aortic valveopen4

Pulmonaryvalve open4

7hen the ventricles are contracting/ the

AV valves are close# an# the semilunar

valves are open. *n the "rontal section

notice the attachment o" the le"t AV valve

to the chor#ae ten#ineae an# papillary

muscles.

Figure 20-= Valves o" the eart

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C o n t r a c t i n g v e n t r i c l e s

Aorta

Aortic sinus

%,F+A+(*$&

Aortic valveopen4

%e"t AV icuspi#4valve close#4

Chor#ae ten#ineaetense4

Papillary musclescontracte#4

%e"t ventriclecontracte#4

() + A t f th & t

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• The Blood Supply to the &eart

• 9 Coronary circulation

• Supplies blood to muscle tissue of heart

• Coronary arteries and cardiac veins

() + Anatom of the &eart

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• The Coronary Arteries

• 3eft and right

• .riginate at aortic sinuses

• &igh blood pressure$ elastic rebound forces blood

through coronary arteries between contractions

() + Anatomy of the &eart

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• (ight Coronary Artery

• Supplies blood to8

• 6ight atrium

• 'ortions of both ventricles

• Cells of sinoatrial 0SA1 and atrioventricular nodes

• &arginal arteries 0surface of right ventricle1

• Posterior interventricular artery


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• %e"t Coronary Artery

• Supplies blood to8

• 3eft ventricle

• 3eft atrium

• Interventricular septum

Figure 20-10 eart 8isease an# eart Attacs

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'arro!ing o" Artery

%ipi# #eposito" pla?ue

Cross-section

+unicaexterna

+unicame#ia

Cross-section

'ormal Artery


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• &eart -isease * Coronary Artery -isease

• Coronary artery #isease CA84

• Areas of partial or complete bloc!age of coronary

circulation

• Cardiac muscle cells need a constant supply of

oxygen and nutrients

• 6eduction in blood flow to heart muscle produces a

corresponding reduction in cardiac performance

• 6educed circulatory supply$ coronary ischemia/

results from partial or complete bloc!age of coronary

arteries


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•

&eart -isease * Coronary Artery -isease• :sual cause is formation of a fatty deposit$ or

atherosclerotic plaque, in the wall of a coronary

vessel

• The pla4ue$ or an associated thrombus 0clot1$ then

narrows the passageway and reduces blood flow

• Spasms in smooth muscles of vessel wall can further

decrease or stop blood flow

• .ne of the first symptoms of CA- is commonly

angina pectoris


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• Angina Pectoris

• In its most common form$ a temporary ischemia

develops when the wor!load of the heart increases

• Although the individual may feel comfortable at rest$

exertion or emotional stress can produce a sensation of

pressure$ chest constriction$ and pain that may radiate

from the sternal area to the arms$ bac!$ and nec!


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• &yocar#ial in"arction &*4/ or heart attack

• 'art of the coronary circulation becomes bloc!ed$ and

cardiac muscle cells die from lac! of oxygen

• The death of affected tissue creates a nonfunctional

area !nown as an infarct

• &eart attac!s most commonly result from severe

coronary artery disease 0CA-1

() ( The Conducting System

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()*( The Conducting System

• &eartbeat

• A single contraction of the heart

• The entire heart contracts in series

• %irst the atria

• Then the ventricles


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• Cardiac 'hysiology

• Two Types of Cardiac #uscle Cells

1. Conducting system

• Controls and coordinates heartbeat

2. Contractile cells

• 'roduce contractions that propel blood


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• The Cardiac Cycle

• Begins with action potential at SA node

• Transmitted through conducting system

• 'roduces action potentials in cardiac muscle cells

0contractile cells1

• Electrocardiogram 0ECG or EKG1

• "lectrical events in the cardiac cycle can be recorded

on an electrocardiogram


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• The Con#ucting System

• A system of speciali/ed cardiac muscle cells

• Initiates and distributes electrical impulses that

stimulate contraction

• Automaticity

• Cardiac muscle tissue contracts automatically


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• Structures of the Conducting System

• inoatrial !"# node * wall of right atrium

• "trio$entricular !"%# node * 5unction between atria

and ventricles

• Conducting cells * throughout myocardium

Figure 20-11a +he Con#ucting System o" the eart

Sinoatrial

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AV un#le

Components o" the con#uctingsystem

Purin5e"iers

un#leranches

Atrioventricular AV4 no#e

*nterno#al

path!ays

SinoatrialSA4 no#e


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• &eart 6ate

• SA node generates ;)

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• The Sinoatrial SA4 'o#e

• In posterior wall of right atrium

• Contains pacemaer cells

• Connected to AV node by internodal pathways

• Begins atrial activation 0Step +1


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• The Atrioventricular AV4 'o#e

• In floor of right atrium

• 6eceives impulse from SA node 0Step (1

• -elays impulse 0Step ?1

• Atrial contraction begins


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• Purin5e Fiers

• -istribute impulse through ventricles 0Step @1

• Atrial contraction is completed

• Ventricular contraction begins


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• Abnormal 'acema!er %unction

• ra#ycar#ia * abnormally slow heart rate

• +achycar#ia * abnormally fast heart rate

• ,ctopic pacemaer

• Abnormal cells

• ,enerate high rate of action potentials

• Bypass conducting system

• -isrupt ventricular contractions


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• The ,lectrocar#iogram 0,C9 or ,@91

• A recording of electrical events in the heart

• .btained by electrodes at specific body locations

• Abnormal patterns diagnose damage


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• %eatures of an "C,

• P !ave

• Atria depolari/e

• (S complex

• Ventricles depolari/e

•

+ !ave

• Ventricles repolari/e


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• Time Intervals between "C, 2aves

• PB( interval

• %rom start of atrial depolari/ation

• To start of 6S complex

• B+ interval

• %rom ventricular depolari/ation

• To ventricular repolari/ation

Figure 20-13a An ,lectrocar#iogram

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,lectro#e placement "or

recor#ing a stan#ar# ,C9.

Figure 20-13 An ,lectrocar#iogram

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=00 msec

S

(S interval

ventricles #epolarie4

&illivolts

(

PB( segment+ !ave

ventricles repolarie4

(

P !ave

atria

#epolarie4

SB+

segment

SB+interval

B+

interval

PB(

interval

Figure 20-1 Car#iac Arrhythmias

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Premature Atrial Contractions PACs4

Paroxysmal Atrial +achycar#ia PA+4

Atrial Firillation AF4

PPP

PPPPPP

Figure 20-1 Car#iac Arrhythmias

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Premature Ventricular Contractions PVCs4

Ventricular +achycar#ia V+4

Ventricular Firillation VF4

PPP

P

+++

Figure 20-1:a +he Action Potential in Seletal an# Car#iac &uscle

(api# 8epolariation +he Plateau (epolariation

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p p (epolariationCauseD 'aE entry

8urationD 3B: msec

,n#s !ithD Closure o"

voltage-gate# "ast

so#ium channels

CauseD Ca2E entry

8urationD 1

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y

• The Car#iac Cycle

• Is the period between the start of one heartbeat

and the beginning of the next

• Includes both contraction and relaxation

()*? The Cardiac Cycle

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y

• Two 'hases of the Cardiac Cycle

• 2ithin any one chamber

1. Systole 0contraction1

2. 8iastole 0relaxation1

Figure 20-1; Phases o" the Car#iac Cycle

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Car#iac

cycle

3

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y

• Blood 'ressure

• In any chamber

• 6ises during systole

• %alls during diastole

• Blood flows from high to low pressure

• Controlled by timing of contractions

• -irected by one*way valves


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y

• Cardiac Cycle and &eart 6ate

• At @ beats per minute 0bpm1

• Cardiac cycle lasts about ;)) msec

• 2hen heart rate increases

• All phases of cardiac cycle shorten$ particularly diastole


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y

• 'hases of the Cardiac Cycle

• Atrial systole

• Atrial diastole

•

Ventricular systole

• Ventricular diastole


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y

• Atrial Systole

+ Atrial systole

• Atrial contraction begins

• 6ight and left AV valves are open

( Atria e5ect blood into ventricles

• %illing ventricles

? Atrial systole ends

• AV valves close

• Ventricles contain maximum blood volume

• Dnown as en#-#iastolic volume ,8V4


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y

• Ventricular Systole

= Ventricles contract and build pressure

• AV valves close cause isovolumetric contraction

:. Ventricular e5ection

• Ventricular pressure exceeds vessel pressure opening the

semilunar valves and allowing blood to leave the ventricle

•

Amount of blood e5ected is called the stroe volume SV4


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• Ventricular Systole

> Ventricular pressure falls

• Semilunar valves close

•

Ventricles contain en#-systolic volume ,SV4$ about =)Eof end*diastolic volume

Figure 20-1< Pressure an# Volume (elationships in the Car#iac CycleA+(*A%

S)S+%,A+(*A%

8*AS+%,

V,'+(*C$%A(8*AS+%,

V,'+(*C$%A(S)S+ ,

A+(*A% 8*AS+%,

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8*AS+%, S)S+%,

Stroevolume

,n#-#iastolic

volume

% e " t

v e n t r i c u l a r

v o l u m e 3 m % 4

P r e s s u r e

3 m m 1

g 4

Aortic valveopens

Aorta

%e"tventricle

%e"t atrium %e"t AVvalve closes AV valves open6 passive ventricular

"illing occurs.

*sovolumetric relaxation occurs.

Semilunar valves close.

Ventricular e5ection occurs.

*sovolumetric ventricular contraction.

Atrial systole en#s6 AV valves close.

Atria e5ect loo# into ventricles.

Atrial contraction egins.

+ime msec4


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• Ventricular -iastole

Ventricular diastole

• Ventricular pressure is higher than atrial pressure

• All heart valves are closed

• Ventricles relax isovolumetric relaxation4

; Atrial pressure is higher than ventricular pressure

• AV valves open

• 'assive atrial filling

• 'assive ventricular filling

Figure 20-1< Pressure an# Volume (elationships in the Car#iac CycleA+(*A%

S)S+%,A+(*A% 8*AS+%,

V,'+(*C$%A(S)S+%,

V,'+(*C$%A( 8*AS+%,

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S)S+%,

AV valves open6 passive ventricular "illing occurs.

*sovolumetric relaxation occurs.

Semilunar valves close.

Ventricular e5ection occurs.

*sovolumetric ventricular contraction.

Atrial systole en#s6 AV valves close.

Atria e5ect loo# into ventricles.

Atrial contraction egins.

+ime msec4

,n#-systolicvolume

Aortic valvecloses

8icroticnotch

%e"t AVvalve opens

% e " t

v e n t r i c u l a r

v o l u m e 3 m % 4

P r e s s u r e

3 m m 1

g 4


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• &eart Sounds

• S+

• 3oud sounds

• 'roduced by AV valves

• S(

• 3oud sounds

• 'roduced by semilunar valves

AI#ATI. The &eart8 Cardiac Cycle


http://heart_card_cycle.mpg/

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• S?$ S=

• Soft sounds

• Blood flow into ventricles and atrial contraction

• eart &urmur

• Sounds produced by regurgitation through valves

Figure 20-1=a eart Soun#s

AorticvalveValve location

Soun#s hear#

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Pulmonaryvalve

Valve location

Soun#s hear#

%e"tAV

valve

(ightAVvalve

Placements o" a stethoscope "or listening to the #i""erent soun#spro#uce# y in#ivi#ual valves

Valve location

Soun#s hear#

Valve location

Soun#s hear#

Figure 20-1= eart Soun#s

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Semilunar valves close

AV valvesopen

AV valvesclose

G8uHG%uH

+he relationship et!een heart soun#s an# ey events in thecar#iac cycle

eart soun#s

P r e s s u r e

3 m m 1

g 4

Ao r t a

Semilunar valves open

%e"tventricle

%e"tatrium

S1SS S

2S3

Figure 20-21 Autonomic *nnervation o" the eart

Car#ioinhiitorycenter

Vagal nucleus

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Car#ioacceleratorycenter

&e#ullaolongata

Vagus ' I4

Spinal cor#

Parasympathetic

Parasympatheticpreganglionic"ier

Synapses incar#iac plexus

Parasympatheticpostganglionic"iers

Car#iac nerve

Sympatheticpostganglionic "ier

Sympatheticpreganglionic"ier

Sympathetic

ganglia cervical

ganglia an#superior thoracic

ganglia J+1 B+K4

Sympathetic

()*= Cardiodynamics

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• &ormonal "ffects on &eart 6ate

• Increase heart rate 0by sympathetic stimulation of

SA node1

•

"pinephrine 0"1

• orepinephrine 0"1

• Thyroid hormone

Corazon 241

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