heart anatomy written copy

ANATOMY OF THE HEART

Moderator: Dr. Ravi Narayan, Consultant Paediatric Cardiologist,

Presented by,

Dr. Agilan M.,

I year, PGDCC, M.S. Ramaiah- Narayana Hrudayalaya.

THE HUMAN HEART

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Heart in pericardial cavity

Figure 18.1

Pericardium

• Pericardial cavity is lined by the pericardium.• Pericardium – a double-walled sac around the

heart composed of:1. A superficial fibrous pericardium2. A deep two-layer serous pericardium

a. The parietal layer lines the internal surface of the fibrous pericardium

b. The visceral layer or epicardium lines the surface of the heart

They are separated by the fluid-filled pericardial cavity. Pericardial fluid acts as a lubricant reducing friction.

The Function of the Pericardium:Protects and anchors the heartPrevents overfilling of the heart with blood

Allows for the heart to work in a relatively friction-free environment

The clear tissue being Lifted up by the scalpel Is the pericardium

Applied anatomy- Pericarditis

• Various pathogens may infect the pericardium.

• The inflamed pericardial surfaces rub against one another.

• Makes a distinct scratching sound.• Cardiac tamponade could occur due to the

increased pericardial fluid in the pericardial cavity. This condition restricts the movement of the heart.

Cardiac Tamponade

Black looking structure is the heart bulging from the pericardial sac.Not only pathogens can cause a cardiac tamponade, but blunt force trauma can also cause it.

Chapter 18, Cardiovascular System 10

External Heart: Anterior View

Figure 18.4b

Gross Anatomy• A conical hollow muscular organ approximately the size of your fist• Location : Middle mediastinum behind sternum, costal cartilages of 3,4,5 ribs

Superior surface of diaphragmLeft of the midlineAnterior to the vertebral column,

• Directed forward and to left . • Anterior most is the apex.• Average measurement: 12cm X9cm • Weight: 325±75 g in men 275± 75 g in women

External features• Sulci:

1.Coronary (atrioventicular) sulci-

a) anterior

b) posterior

1.Interterial groove visible posteriorly

2.Interventricular sulci/ groove

3.Crux is the posterior basal surface at juction of coronary and posterior interventricular sulci and internally atrial septum joins the venticular septum

Surfaces • Diaphragmatic or inferior

• Anterior of sternocostal

• Left surface

Borders • Right- SVC and RA

• Left- LV and La

• Inferior- RV and laterally LV

• Arteries – right coronary artery (in atrioventricular groove) and the posterior interventricular artery (in interventricular groove)

• Veins – great cardiac vein, posterior vein to left ventricle, coronary sinus, and middle cardiac vein

External Heart: Vessels that Supply/Drain the Heart (Posterior View)

The anterior and posterior interventricular sulci are shallowerdepressions that mark the boundary line between the leftand right ventricles.

These areas usually contain a large amount of fat. The sulcicontain the arteries and veins that feed the heart.

The heart has an attached base and a free apex.

The inferior tip is called the apex.

In a typical adult the heart measures approximately 12.5 cmfrom the base to the tip.

The apex reaches to the fifth intercostal space, 7.5 cm to theleft of the midline.

Surface Anatomy :

Right atrium anterior and to the right of left atrium.

Left atrium a midline structure

Right ventricle anterior and to the right of left

Ventricle.

Pulmonary artery anterior and to the left of aorta

Coronary arteries on surface follow A-V groove

and interventricular septum.

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• Vessels returning blood to the heart include:1. Superior and inferior venae cavae2. Right and left pulmonary veins

• Vessels conveying blood away from the heart include:

1. Pulmonary trunk, which splits into right and left pulmonary arteries

2. Ascending aorta (three branches) –a. Brachiocephalicb. Left common carotidc. Subclavian arteries

External Heart: Major Vessels of the Heart (Anterior View)

• Arteries – right and left coronary (in atrioventricular groove), marginal, circumflex, and anterior interventricular arteries

• Veins – small cardiac, anterior cardiac, and great cardiac veins

External Heart: Vessels that Supply/Drain the Heart (Anterior View)


External Heart: Posterior View

• Vessels returning blood to the heart include:

1. Right and left pulmonary veins

2. Superior and inferior venae cavae

• Vessels conveying blood away from the heart include:

1. Aorta

2. Right and left pulmonary arteries

External Heart: Major Vessels of the Heart (Posterior View)

Anatomical position of theheart from Grays Anatomy

Anomalous-Anatomical position of the heart

OVERVIEW OF THE CARDIOVASCULAR SYSTEM

• Pulmonary circuit

• Systemic circuit

• Arteries (Including the coronary arteries)

• Veins (Including the coronary veins)

• Capillaries (Arterioles & Venules)

• Four chambers of the heart

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Pathway of Blood Through the Heart and Lungs

• Right atrium tricuspid valve right ventricle

• Right ventricle pulmonary semilunar valve pulmonary

arteries lungs

• Lungs pulmonary veins left atrium

• Left atrium bicuspid valve left ventricle

• Left ventricle aortic semilunar valve aorta

• Aorta systemic circulation

Heart Wall

• Epicardium – visceral layer of the serous pericardium

• Myocardium – cardiac muscle layer forming the bulk of the heart

• Fibrous skeleton of the heart – crisscrossing, interlacing layer of connective tissue

• Endocardium – endothelial layer of the inner myocardial surface

Walls of the Heart

Myocardial Thickness and Function

Thickness of myocardium varies according to the function of the chamber

Atria are thin walled, deliver blood to adjacent ventriclesVentricle walls are much thicker and stronger

– right ventricle supplies blood to the lungs (little flow resistance)

– left ventricle wall is the thickest to supply systemic circulation

Thickness of Cardiac Walls

Myocardium of left ventricle is much thicker than the right.

Chambers of the heart

• Right atrium RA

• Right ventricle RV

• Left Atrium LA

• Left Ventricle LV• When not filled with blood, the outer portion of each

atrium deflates and becomes a lumpy, wrinkled flap.• This extension is called the auricle (looks like an

external ear).

Cardiac Chambers

• a) Right atrium Wide based blunt appendage, crista terminalis separates trabeculated from non-trabeculated portion.

• b) Left atrium Long, narrow appendage, smooth walls.

• c) Right ventricle Coarsely trabeculated inlet/sinus, outlet portion.

• d) Left ventricle Fine trabeculations inlet/sinus and outlet portions.


Gross Anatomy of chambers: Frontal Section

Figure 18.4e

Atria of the Heart

• Atria are the receiving chambers of the heart

• Each atrium has a protruding auricle

• Pectinate muscles mark atrial walls

• Blood enters right atria from superior and inferior venae cavae and coronary sinus

• Blood enters left atria from pulmonary veins

Right Atrium• SVC

- IVC

- Crista terminalis

- Coronary sinus

- Tricuspid valve

- Fossa ovalis

- Triangle of Koch

- Tendon of Todaro

- Inferior isthmus

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Ventricles of the Heart• Ventricles are the discharging chambers of

the heart

• Papillary muscles and trabeculae carneae muscles mark ventricular walls

• Right ventricle pumps blood into the pulmonary trunk

• Left ventricle pumps blood into the aorta

View from the right side of the heart.

1 2

3

Chordae tendineae

Papillary muscle

Ventricular Differences

• The anatomical differences between the right and left ventricles are as follows:

• The right ventricle is relaetively thin. The left ventricle has a massive muscular wall.

Interventricular septum

InteratrialSeptum. Lateral view

The pectinate musclesare prominentmuscular ridges foundin the atrial walls

LeftVentricleHeartWall

Right Ventricle Heart Wall

Fibrous Skeleton Of The HeartFibrous Skeleton Of The Heart

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Heart Valves• Heart valves ensure unidirectional blood flow

through the heart

• Atrioventricular (AV) valves lie between the atria and the ventricles– AV valves prevent backflow into the atria when

ventricles contract

• Chordae tendineae anchor AV valves to papillary muscles

Atrioventricular Valves

• Prevent backflow of blood from the ventricles back into the atria.

• Chordae tendineae and papillary muscles play an important role in this process.

• Ventricular diastole the ventricles relax and the ventricles refill.

• The chordae tendineae are loose and offer no resistance to the flow of blood.

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Heart Valves

Heart Valves

During ventricular systole the ventricles begin to contractblood moving back towards the atria swings the cuspstogether closing the valves.

The chordae tendineae and papillary muscles stops thecusps from swinging into the atria.

If those two structures are cut or damaged the valves actas swinging doors, and there is backflow, orregurgitation.

Mitral valve damage can especially occur in womenafter pregnancy.

Mitral valve -Anatomy

Ann Thorac Surg 1998: 65:1025-1031.J Heart Valve Dis 1995; 4:70-75.Cardiol Clin. 2000; 18: 731-50.

Anatomic Classification Schema:Mitral Valve Segments

Duran Classification

Am Heart J. 2000;139: 378-87.

Mitral Valve Prolapse

Tricuspid Valve

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Semilunar Heart Valves• Semilunar valves prevent backflow of

blood into the ventricles

• Aortic semilunar valve lies between the left ventricle and the aorta

• Pulmonary semilunar valve lies between the right ventricle and pulmonary trunk


Atrioventricular Valve Function

Figure 18.9


Semilunar Valve Function

Figure 18.10

Aortic valve – Anatomy

The AORTIC ROOT has four anatomic components:

• The aortic sinuses or sinuses of Valsalva

• The aortic annulus or aortoventricular junction

• The leaflets

• The sinotubular junction

SINGLE FUNCTIONAL

UNIT

Aortic Root - Anatomy

Sinotubular Junctinon

MyocardiumFibrous tissueAnterior leaflet of the mitral valve Membranous septum

Normal: 55% 45%Marfan/Bicuspid aortic valve: 65% 35%

N L R

Histology:

The aortic root is in fibrous continuity with the anterior leaflet of the mitral valve and the membranous septum; connective tissue (fibrous strands) unites the aortic root to the interventricular septum.

Aortic Annulus (aortoventricular junction)

The highest point of the trigone where the leaflets meet is called the commissure. The commissures are localised immediately below the Sinotubular Junction.

They are attached to the aortic root in a semilunar fashion

Valve Leaflets

The triangular space underneath the leaflet (trigone) is part of the left ventricle.

The 2 trigones underneath the commissures of the noncoronary leaflet are fibrous structures, whereas the other underneath the commissure between the right and the left leaflets is mostly a muscular structure.

Sinuses of ValsalvaSinuses of Valsalva

The segment of the arterial wall of the aortic root delineated by a leaflet proximally and by the sinotubular junction distally is called the aortic sinus or sinus of Valsalva.

They are 3 elliptical inlets that have a very important role in the dynamics of circulation :• Guaranteeing coronary artery perfusion during systole;•Creating eddies to close the aortic leaflets during diastole

It represents the terminal edge of the aortic root and it is constituted by the imaginary line that connects together the 3 commissures.

Young adults

AA>STJ

AdultsAA = STJ

ElderlyAA<STJ

BASE = Aortic Annulus (AA)

Sinotubular Junction

aortic stenosis

aortic valve fibrosis

aortic valve calcification

AORTIC VALVE PATHOLOGY

AR due to Abnormalities of the Leaflets

Cusp perforation

Infective endocarditis

Trauma

Iatrogenic cause

• Excess of tissue• Disrupted commissure• Commissural malposition

Cusp prolapse


Restrictive motion

Fibrous thickening


Sinotubular junction dilatation

Dilatation of the sinotubular junction displaces the commissures outward and prevents

the aortic leaflets from coapting, with resulting central aortic insufficiency

AR - Abnormalities of the Aortic Wall

Annular dilatation

AR - Abnormalities of the Aortic Wall

•

• Marfan syndrome

• Connective tissue diseases

• Ventricular dilatation

• Chronic hypertension

Aortic root aneurysm:

ST junction dilatation

+

Sinuses of Valsalva aneurysm

AI due to Abnormalities of the Aortic Wall

CONDUCTION SYSTEM

Conduction System

• Sinoatrial node - anterolateral RA

• Interatrial conduction pathways - not well defined and somewhat controversial

• Inferior isthmus (right atrium) anterior Bachman's bundle (left atrium), middle Wenkebachs, posterior Thorel

• Atrioventricular node - triangle of Koch

• Bundle of His - AV node to membranous septum, usually located on the inferior/posterior wall of the membranous septum

• Left bundle branch - left ventricular septal surface into multiple branches

• Right bundle branch - below medial papillary muscle via septal and moderator bands to anterior papillary muscle

IMPULSE

SA NODE

Heart Blood Supply

• Coronary circulation demands high oxygen and nutrients for the cardiac muscle cells.

• Coronary arteries originate at the base of the ascending aorta.

• Interconnections between arteries called anastomoses ensure a constant blood supply.

Coronary Circulation: Arterial Supply


Coronary Circulation: Venous Supply

Figure 18.7b

Great, Posterior, small,Anterior, Middle CardiacVeins carry blood fromThe coronary capillariesTo the coronary sinus.

Left coronary artery suppliesThe left ventricle. CirculflexCurves left meeting withThe right coronary artery.Left anterior decendingSupplies the posteriorDecending artery (interventricular).

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Microscopic Anatomy of Heart Muscle

• Cardiac muscle is striated, short, fat, branched, and interconnected

• The connective tissue endomysium acts as both tendon and insertion

• Intercalated discs anchor cardiac cells together and allow free passage of ions

• Heart muscle behaves as a functional syncytium

InterActive Physiology®: Cardiovascular System: Anatomy Review: The Heart


Microscopic Anatomy of Heart Muscle

Figure 18.11

Extrinsic Innervation of the Heart• Heart is

stimulated by the sympathetic cardioacceleratory center

• Heart is inhibited by the parasympathetic cardioinhibitory center

Thank You !!!

heart anatomy written copy

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