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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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An Introduction to the Cardiovascular System
• 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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An Introduction to the Cardiovascular System
• 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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An Introduction to the Cardiovascular System
•
%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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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• 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.
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
Ascen#ingaorta
Parietalpericar#ium
Superior vena cava
Auricle o" right atrium
(*9+ A+(*$&
(ight coronaryartery
Coronary sulcus
(*9+ V,'+(*C%,
&arginal rancho" right coronary artery
Auricle o" le"t atrium
Pulmonarytrun
Firouspericar#ium
Parietal pericar#ium"use# to #iaphragm
Anterior interventricular
sulcus
%,F+V,'+(*C%,
&a5or anatomical "eatures on the anterior sur"ace.
Fi 20 3 +h S "i i l A t " th t
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Figure 20-3 +he Super"icial Anatomy o" the eartArch o" aorta
(ight pulmonaryartery
Superior
vena cava
(ightpulmonaryveins superior an# in"erior4
*n"erior vena cava
Fat an# vessels in posterior interventricular sulcus
(*9+V,'+(*C%,
%,F+V,'+(*C%,
(*9+
A+(*$&
%,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.
Fi 20 3 +h S "i i l A t " th t
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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
:
;
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10
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()*+ Anatomy of the &eart
• The &eart 2all
1. ,picar#ium
2. &yocar#ium
3. ,n#ocar#ium
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()*+ Anatomy of the &eart
•
,picar#ium 0.uter 3ayer1• Visceral pericardium
• Covers the heart
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()*+ Anatomy of the &eart
•
&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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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• Internal Anatomy and .rgani/ation
• *nteratrial septum separates atria
• *nterventricular septum separates ventricles
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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• 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
*nterventricular septum
%,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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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• 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
*nterventricular septum
%,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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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• 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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()*+ Anatomy of the &eart
• (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
() + Anatomy of the &eart
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()*+ Anatomy of the &eart
• %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
() + Anatomy of the &eart
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()*+ Anatomy of the &eart
• &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
() + Anatomy of the &eart
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()*+ Anatomy of the &eart
•
&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
() + Anatomy of the &eart
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()*+ Anatomy of the &eart
• &eart -isease * Coronary Artery -isease
• 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!
() + Anatomy of the &eart
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()*+ Anatomy of the &eart
• &eart -isease * Coronary Artery -isease
• &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
() ( The Conducting System
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()*( The Conducting System
• Cardiac 'hysiology
• Two Types of Cardiac #uscle Cells
1. Conducting system
• Controls and coordinates heartbeat
2. Contractile cells
• 'roduce contractions that propel blood
() ( The Conducting System
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()*( The Conducting System
• 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
()*( The Conducting System
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()*( The Conducting System
• 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
()*( The Conducting System
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()*( The Conducting System
• 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
()*( The Conducting System
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()*( The Conducting System
• &eart 6ate
• SA node generates ;)
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() ( The Conducting System
• 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
()*( The Conducting System
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() ( The Conducting System
• The Atrioventricular AV4 'o#e
• In floor of right atrium
• 6eceives impulse from SA node 0Step (1
• -elays impulse 0Step ?1
• Atrial contraction begins
()*( The Conducting System
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() ( The Conducting System
• Purin5e Fiers
• -istribute impulse through ventricles 0Step @1
• Atrial contraction is completed
• Ventricular contraction begins
()*( The Conducting System
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() ( The Conducting System
• 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
()*( The Conducting System
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() ( The Conducting System
• 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
()*( The Conducting System
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() ( The Conducting System
• %eatures of an "C,
• P !ave
• Atria depolari/e
• (S complex
• Ventricles depolari/e
•
+ !ave
• Ventricles repolari/e
()*( The Conducting System
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() ( The Conducting System
• 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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• 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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• 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
()*? The Cardiac Cycle
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• 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
()*? The Cardiac Cycle
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• 'hases of the Cardiac Cycle
• Atrial systole
• Atrial diastole
•
Ventricular systole
• Ventricular diastole
()*? The Cardiac Cycle
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• 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
()*? The Cardiac Cycle
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• 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
()*? The Cardiac Cycle
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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
()*? The Cardiac Cycle
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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
()*? The Cardiac Cycle
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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
()*? The 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