6-7 translist

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Struktur dan FungsiJantung Dasar

Ken Young Lin

Elazer R. Edelman

Gary Strichartz

Leonard S. Lilly

B A B

1ANATOMI DAN HISTOLOGI JANTUNG

Perikardium

Anatomi permukaan dari Jantung

Struktur Internal dari Jantung

Impulse-Conducting System

Innervasi Jantung

Pembuluh darah Jantung

Histology of entricular !yocardial Cells

ELEKTROFISIOLOGI DASAR

Ion !ovement and Channels

"esting Potential

no#ledge of normal cardiac structure

and function is crucial to understanding

diseases that afflict the heart$ %his chapter re-

vie#s basic cardiac anatomy and electrophysi-

ology as #ell as the events that lead to cardiac

contraction$

ANATOMI DAN HISTOLOGI

JANTUNG

Although the study of cardiac anatomy dates

back to ancient times& interest in this field

has recently gained momentum$ %he devel-

opment of sophisticated cardiac imaging

procedures such as coronary angiography&

echocardiography& computed tomography&and magnetic resonance imaging has made

Potensial Aksi

Periode "efrakter

Impulse Conduction

'ormal Se(uence of Cardiac )epolari*ation

EXCITATION–CONTRACTION COULING

Contractile Proteins in the !yocyte

Calcium-Induced Calcium "elease and the

Contractile Cycle

-Adrenergic and Cholinergic Signaling

essential an intimate kno#ledge of the spatial

relationships of cardiac structures$ Such in-

formation also proves helpful in understand-

ing the pathophysiology of heart disease$ %his

section emphasi*es the aspects of cardiac

anatomy that are important to the clinician+

that is& the ,functional anatomy$

!rikardiu"

%he heart and roots of the great vessels are

enclosed by a fibroserous sac called the peri-

cardium ./ambar 1$10 Struktur ini mengandung

dua lapisan a strong outer fibrous layer and an

inner serosal layer$ %he inner serosal layer ad-

heres to the e2ternal #all of the heart and is

#

3

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4ungsi dan Struktur Jantung dasar

$

Vena

cava

superior

Vena

cava

inferior

Aorta

Arteri

Pulmonal

Jantungdengan

pericardium

Diafragma

more posteriorly& they form only a small strip

of this anterior surface$ %he in%!ri&r surface of

the heart is formed by both ventricles& primarily

the left$ %his surface of the heart lies along the

diaphragm5 hence& it is also referred to as the

diaphragmatic surface$

6bserving the chest from an anteroposte-

rior vie# .as on a chest radiograph5 see Chap-

ter 70& four recogni*ed borders of the heart are

apparent$ %he right border is established by

the right atrium and is almost in line #ith the

superior and inferior venae cavae$ %he infe-

Figur! #'#' T(! )&siti&n &% t(! (!art in t(! *(!st' %hesuperior vena cava& aorta& and pulmonary artery e2it superi-orly& #hereas the inferior vena cava pro8ects inferiorly$

called the +is*!ra, )!ri*ardiu"$ %he visceral pericardium reflects back on itself and lines

the outer fibrous layer& forming the )ari!ta,

)!ri*ardiu"$ %he space bet#een the visceral

and parietal layers contains a thin film of peri-

cardial fluid that allo#s the heart to beat in a

minimal-friction environment$

%he pericardium is attached to the sternum

and the mediastinal portions of the right and left

pleurae$ Its many connections to the surround-

ing structures keep the pericardial sac firmly

anchored #ithin the thora2 and therefore helpto maintain the heart in its normal position$

9manating from the pericardium in a supe-

rior direction are the aorta& the pulmonary ar-

tery& and the superior vena cava .see 4ig$ 1$10$

%he inferior vena cava pro8ects through the

pericardium inferiorly$

Sur%a*! Anat&"- &% t(!

H!art

%he heart is shaped roughly like a cone and

consists of four muscular chambers$ %he right

and left ventricles are the main pumping cham-

bers$ %he less muscular right and left atria de-

liver blood to their respective ventricles$

Several terms are used to describe the

heart:s surfaces and borders .4ig$ 1$;0$ %he

a)!. is formed by the tip of the left ventricle&

#hich points inferiorly& anteriorly& and to the

left$ %he /as! or posterior surface of the heart

is formed by the atria& mainly the left& and lies

bet#een the lung hila$ %he ant!ri&r surface of

the heart is shaped by the right atrium and ven-

tricle$ <ecause the left atrium and ventricle lie

rior border is nearly hori*ontal and is formed

mainly by the right ventricle& #ith a slight

contribution from the left ventricle near the

ape2$ %he left ventricle and a portion of the left

atrium make up the left border of the heart&#hereas the superior border is shaped by both

atria$ 4rom this description of the surface of

the heart emerge t#o basic ,rules of normal

cardiac anatomy .10 right-sided structures lie

mostly anterior to their left-sided counterparts&

and .;0 atrial chambers are located mostly to

the right of their corresponding ventricles$

Int!rna, Stru*tur! &% t(! H!art

4our ma8or valves in the normal heart direct blood flo# in a for#ard direction and prevent

back#ard leakage$ %he atrioventricular valves

.tricuspid and mitral0 separate the atria and

ventricles& #hereas the semilunar valves .pul-

monic and aortic0 separate the ventricles from

the great arteries .4ig$ 1$70$ All four heart valves

are attached to the fibrous *ardia* sk!,!t&n&

#hich is composed of dense connective tissue$

%he cardiac skeleton also serves as a site of at-

tachment for the ventricular and atrial muscles$

%he surface of the heart valves and the in-

terior surface of the chambers are lined by a

single layer of endothelial cells& termed the

!nd&*ardiu"$ %he subendocardial tissue

contains fibroblasts& elastic and collagenous

fibers& veins& nerves& and branches of the con-

ducting system and is continuous #ith the

connective tissue of the heart muscle layer& the

myocardium$ %he "-&*ardiu" is the thickest

layer of the heart and consists of bundles of

cardiac muscle cells& the histology of #hich is

described later in the chapter$ 92ternal to the

myocardium is a layer of connective tissue and

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ABrachiocephalic a. Left common carotid a.

Left subclavian a.

Superior vena cava

Aortic arch

Left pulmonary a.

Right pulmonary a.

Right pulmonary vv.

Right atrium

Right heart border

Left pulmonary vv.

Left atrial appendage

Left ventricle

Left heart border

Right ventricle

nferior vena cava

Anterior interventricular

groove

nferior heart border

B

Ape!

Left common carotid a.

Left subclavian a.Brachiocephalic a.

A"ygous v.

Aortic arch

Lig. arteriosum

Left pulmonary a.

Left pulmonary vv.

Left ventricle

Left

atrium

Superior vena cava

Right pulmonary a.

Right pulmonary vv.

Right atrium

nferior vena cava

nferior heart border

Figur! #'$' T(! (!art and gr!at +!ss!,s' A' %he anterior vie#$ 0' %he posterior aspect .or base0& as vie#edfrom the back$ a& artery5 lig& ligamentum5 vv& veins$

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Anterior

Pulmonic

valve

Aortic

valve

#itral

valve

Annulus

fibrosus

$ricuspid

valve

Annulus

fibrosus

Posterior

Figur! #'1' T(! %&ur (!art +a,+!s +i!2!d %r&" a/&+! 2it( atria r!"&+!d' %hefigure depicts the period of ventricular filling .diastole0 during #hich the tricuspidand mitral valves are open and the semilunar valves .pulmonic and aortic0 areclosed$ 9ach annulus fibrosus surrounding the mitral and tricuspid valves is thicker than those surrounding the pulmonic and aortic valves5 all four contribute to theheart:s fibrous skeleton& #hich is composed of dense connective tissue$

adipose tissue through #hich pass the larger

blood vessels and nerves that supply the heart

muscle$ %he !)i*ardiu" is the outermostlayer of the heart and is identical to& and 8ust

another term for& the visceral pericardium pre-

viously described$

"ight Atrium and entricle

6pening into the rig(t atriu" are the supe-

rior and inferior venae cavae and the coronary

sinus .4ig$ 1$=0$ %he venae cavae return de-

o2ygenated blood from the systemic veins into

the right atrium& #hereas the coronary sinus

carries venous return from the coronary arter-

ies$ %he interatrial septum forms the postero-

medial #all of the right atrium and separates

it from the left atrium$ %he tri*us)id +a,+! is

located in the floor of the atrium and opens

into the right ventricle$

%he rig(t +!ntri*,! .see 4ig$ 1$=0 is roughly

triangular in shape& and its superior aspect

forms a cone-shaped outflo# tract& #hich leads

to the pulmonary artery$ Although the inner

#all of the outflo# tract is smooth& the rest

of the ventricle is covered by a number of ir-

regular bridges .termed tra/!*u,a! *arn!a!0

that give the right ventricular #all a sponge-

like appearance$ A large trabecula that crossesthe ventricular cavity is called the "&d!rat&r

/and$ It carries a component of the right bundle

branch of the conducting system to the ventri-

cular muscle$

%he right ventricle contains three )a)i,,ar-

"us*,!s& #hich pro8ect into the chamber and

via their thin& stringlike *(&rda! t!ndin!a!

attach to the edges of the tricuspid valve leaf-

lets$ %he leaflets& in turn& are attached to the

fibrous ring that supports the valve bet#een

the right atrium and ventricle$ Contraction of

the papillary muscles prior to other regions

of the ventricle tightens the chordae tendineae&

helping to align and restrain the leaflets of

the tricuspid valve as they are forced closed$

%his action prevents blood from regurgitat-

ing into the right atrium during ventricular

contraction$

At the ape2 of the right ventricular outflo#

tract is the )u,"&ni* +a,+!& #hich leads to the

pulmonary artery$ %his valve consists of three

cusps attached to a fibrous ring$ )uring rela2ation

of the ventricle& elastic recoil of the pulmonary

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AortaPulmonary artery

Pulmonic valve

Superior vena cava

Right atrium

nferior vena cava

nterventricular septum

#oderator band

$rabeculaecarneae

%oronary sinus

$ricuspid valve Right ventriclePapillary muscles

Figur! #'3' Int!ri&r stru*tur!s &% t(! rig(t atriu" and rig(t +!ntri*,!' .!odified from /oss C!$ Gray’s Anatomy$ ;>th ed$ Philadelphia& PA1 ?ea @ 4ebiger5 1>A7B=A$0

arteries forces blood back to#ard the heart& dis-

tending the valve cusps to#ard one another$

%his action closes the pulmonic valve and pre-

vents regurgitation of blood back into the right

ventricle$

?eft Atrium and entricle

9ntering the posterior half of the ,!%t atriu" are

the four pulmonary veins .4ig$ 1$B0$ %he #all

of the left atrium is about ; mm thick& being

slightly greater than that of the right atrium$

%he mitral valve opens into the left ventricle

through the inferior #all of the left atrium$

%he cavity of the ,!%t +!ntri*,! is appro2i-

mately cone shaped and longer than that of

the right ventricle$ In a healthy adult heart& the#all thickness is > to 11 mm& roughly three

times that of the right ventricle$ %he aortic

vestibule is a smooth-#alled part of the left

ventricular cavity located 8ust inferior to the

aortic valve$ Inferior to this region& most of

the ventricle is covered by trabeculae carneae&

#hich are finer and more numerous than those

in the right ventricle$

%he left ventricular chamber .see 4ig$ 1$B<0

contains t#o large papillary muscles$ %hese are

larger than their counterparts in the right ven-tricle& and their chordae tendineae are thicker

but less numerous$ %he chordae tendineae of

each papillary muscle distribute to both leaf-

lets of the "itra, +a,+!$ Similar to the case

in the right ventricle& tensing of the chordae

tendineae during left ventricular contraction

helps restrain and align the mitral leaflets& en-abling them to close properly and preventing

the back#ard leakage of blood$

%he a&rti* +a,+! separates the left ventricle

from the aorta$ Surrounding the aortic valve

opening is a fibrous ring to #hich is attached

the three cusps of the valve$ Just above the

right and left aortic valve cusps in the aortic

#all are the origins of the right and left coro-

nary arteries .see 4ig$ 1$B<0$

Interventricular Septum%he interventricular septum is the thick #all

bet#een the left and right ventricles$ It is

composed of a muscular and a membranous

part .see 4ig$ 1$B<0$ %he margins of this sep-

tum can be traced on the surface of the heart

by follo#ing the anterior and posterior in-

terventricular grooves$ 6#ing to the greater

hydrostatic pressure #ithin the left ventricle&

the large muscular portion of the septum

bulges to#ard the right ventricle$ %he small&

oval-shaped membranous part of the septumis thin and located 8ust inferior to the cusps of

the aortic valve$

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A

Aorta

Vena pulmonal&anan

Arter i

Pulmonal

Atrium &iri

&atup Aorta

Septumnterventri'ular

(elai Posterior&atup mitral

Ventricle&anan

)tot Papilaris

Ventri'el &iri

B

Arter i pulmonalis

Asal dari arteri'oroner 'anan

Septumnterventricular parsmembrana

Septumnterventricularpars mus'ularis

mus'uluspapilarisPosterior

$rabe'ulaecarneae

A)R$A %uspid Posterior'atup aorta

Asal dari arteri'oroner 'iri

%uspid Anterior'atup mitral

&ordaetendineae

mus'uluspapilaris

Anterior

Ga"/ar #'4' Struktur /agian da,a" dari +!ntrik!, dan atriu" kiri' A' %he left)aerah masuk dan keluar ventrikel kiri .?0 dan atrium kiri 0' Struktur bagian dalamruang ventrikel kiri$ .)iubah dari Agur A!"& ?ee !J$ Grant’s Atlas of Anatomy$ 9disi ke->$<altimore& !)1 illiams @ ilkins5 1>>1B>$0

Dntuk menyimpulkan poin-poin fungsi

anatomis yang di8abarkan dalam bagian ini&

berikut ini ada tin8auan aliran darah melalui

8antung darah miskin oksigen masuk ke 8antung

melalui vena kava superior dan inverior& yang

memasuki atrium kanan$ Aliran darah berlan8ut

mele#ati orifisium katup trikuspidalis ke ventrikel

kanan$ 3ontraksi dari ventrikel kanan mengalirkan

darah melalui katup pulmonal ke arteri pulmonalis

lalu ke paru& di mana karbon dioksida dilepaskan

dan oksigen diserap$ )arah kaya oksigen

selan8utnya masuk ke 8antung melalui vena

pulmonalis menu8u atrium kiri dan kemudian

melalui katup mitral menu8u ventrikel kiri$

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kontraksi ventrikel kiri memompa darah kaya

oksigen mele#ati katup aorta menu8u aorta& yang

kemudian didistribusikan ke seluruh 8aringan

tubuh$

Sist!" I")u,s5K&nduksi

Sistem impuls-konduksi ./br$ 1$E0 terdiri dari

berbagai sel khusus yang memicu denyut 8antung

dan secara kelistrikan mengkoordinasi kontraksi

ruang-ruang 8antung$ N&dus sin&atria, 6SA7

merupakan sebuah massa kecil serabut otot 8antung

khusus di dinding atrium kanan$ 'odus ini terletak

di sebelah kanan 8alan masuk vena kava superior

dan normalnya memicu impuls listrik untuk

kontraksi$ N&dus atri&+!ntriku,ar 6A87 terletak di ba#ah endokardium di bagian inferoposteror

bagian septum interatrial$

)i ba#ah nodus A terdapat /und!, His& yang

terletak menembus posterior septum

interventrikular$ )i dalam septum& bundel his

bercabang men8adi serabut pipih yang men8alar

hingga ke sebelah kiri septum& yang dikenal

sebagai cabang bundel kiri .left bundle branch

(LBB)0$ dan struktur padat mirip kabel di bagian

kanan& cabang bundel kanan .right bundle branch

(BB)0$

"<< tebal dan terletak 8auh di dalam otot

septum interventikular dan meman8ang hingga ke

apeks$ )i dekat persambungan antara septum

interventrikular dan dinding anterior ventrikel

kanan& "<< men8adi subendokartial dan

bercabang dua$ satu cabang ber8alan men8adi

moderator band mele#ati ruang ventrikel kanan&

sedangkan cabang satunya meman8ang hingga

u8ung ventrikel$ Cabang-cabang tersebut akhirnya

men8alar men8adi pleksus yang beranastomosis

dengan rapi di sepan8ang ventrikel kanan$

Secara fungsional& ?<< terbagi men8adi

fasikulus anterior dan posterior serta cabang

kecil menu8u septum$ 4asikulus anterior

ber8alan menu8u apeks& membentuk pleksus

subendokardial di daerah muskulus papilaris

anterior$ 4asikulus posterior ber8alan menu8udaerah muskulus papilaris posterior5 yang

kemudian terbagi men8adi pleksus

subendokardial yang menyebar ke seluruh

ventrikel kiri$

Pleksus subendokardial dari kedua ventrikel

menyebarkan s!ra/ut urkin9! ke otot ventrikel$

Impuls dalam sistem His-Purkin8e a#alnya di

transmisikan ke

*odus Sinoatrial

Sinus %oronaria

*odus Atrioventri'ular

Bundel (is

Right bundle branch

#oderator band

&atup #itral

Pars #embranosa septum 'e V

Bifur'asiobundle (is

Pars #us'ularis

Septum 'e V

Left bundle branch

Serabut Pur'in+e diba,ah endo'ardiummus'ulus papilaris

Ga"/ar #':' K&")&n!n uta"a sist!" k&nduksi 9antung' Sistem ini yaitu nodus sino-atrial&nodus atrioventrikular& bundel His kanan dan kiri& d an serabut Purkin8e$ Moderator and menyalurkan bagian be sar bun dle kanan $ I& interventrikular$

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