Anatomy and physiology of the heart

Embryology of normal heart and of the T4F

The congenital heart defects and the T4F

Anatomy and Physiologyof the Heart

Fallot’ Projecthttp://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_anatomy.htmlhttp://www.texasheartinstitute.org/hic/anatomy/anatomy2.cfmhttp://www.gwc.maricopa.edu/class/bio202/cyberheart/hartint0.htmwww.biosbcc.net/b100cardio/htm/heartant.htm

The Cardiovascular System

LocationThe heart is located between the lungs in the middle of the chest, behind and slightly to the left of the breastbone (sternum).

11

2

23

Heterotaxiaisomerism

definitions

• Dextrocardie:

– dextrocardie, traduisant la seule inversion de la pointe du cœur (normalement orientée à gauche).

– Mésocardie / lévocardie

• Hétérotaxie:

– Le terme « hétérotaxie » signifie étymologiquement « positionnement différent » (heteros, différent ; taxos, positionnement).

– désigne une malformation congénitale se traduisant par un mauvais placement des organes internes, pairs ou non, dans le thorax et/ou la cavité abdominale, par rapport à un axe de symétrie droite/gauche.

– (1) situs inversus ou situs totalis, traduisant une inversion complète des organes internes « en miroir » par rapport à un sujet dit normal ; (2) situs ambigus, traduisant une inversion partielle

• Isomérisme:

– Dédoublement d’un côté droit ou gauche

Visceral and Heart Situs

Pectinae muscles

Isomérisme droit

Left Isomerism

appendages

Situs inversus

Situs solitus

Right isomerism

InsertionsA double-layered membrane called the pericardium surrounds your heart like a sac.

The outer layer of the pericardium surrounds the roots of your heart's major blood vessels and is attached by ligaments to your spinal column, diaphragm, and other parts of your body.

The inner layer of the pericardium is attached to the heart muscle. A coating of fluid separates the two layers of membrane, letting the heart move as it beats, yet still be attached to your body.

Position of the cavities and great arteries

front

back

leftright

The Cardiovascular System

Atria / Appendagesright atrial appendage : a small conical muscular pouch attached to the right atrium The LAA is a windsock-like structure that

is long, tubular and hooked.

Right ventricle

Tricuspid valve3 leaflets

Chordae tendineae

Papillary muscles

3 chambersinlettrabecular partoutlet

Specific parts of the right ventricleThe muscular strap reinforcing the septal surface, extending into the apical trabecular component is named the septomarginal trabeculation (septal band in USA), which has two limbs, the antero-cephalad or antero-superior limb going towards the papillary muscles of the tricuspid valve and the postero-caudal or postero-inferior limb running towards the pulmonary leaflets.

The multiple muscular bundles extending from the septomarginal trabeculation and ran onto the parietal wall of the outflow tract is named the septoparietal trabeculations. One of them is named moderate band, which run towards the medio papillary muscle of the tricuspid valve.

Left ventricleMitrale valve2 leaflets

anteriorposterior

Chordae tendineae

2 papillary musclesanterolateralposteromedial

3 chambersinlettrabecular partoutlet Left view

The conduction systemThe electrical signal begins in the sinoatrial (SA) node, located at the top of the right atrium. The SA node is sometimes called the heart's "natural pacemaker." When an electrical impulse is released from this natural pacemaker, it causes the atria to contract.

The signal then passes through the atrioventricular (AV) node. The AV node checks the signal and sends it through the muscle fibers of the ventricles, causing them contract.

The SA node sends electrical impulses at a certain rate, but the heart rate may still change depending on physical demands, stress, or hormonal factors.

Coronary CirculationThe aorta branches off into two main coronary blood vessels (also called arteries). These coronary arteries branch off into smaller arteries, which supply oxygen-rich blood to the entire heart muscle.

The right coronary artery supplies blood mainly to the right side of the heart. The right side of the heart is smaller because it pumps blood only to the lungs.

The left coronary artery, which branches into the left anterior descending artery and the circumflex artery, supplies blood to the left side of the heart. The left side of the heart is larger and more muscular because it pumps blood to the rest of the body.

Coronary sinus

The Heart Valves

Cardiac Cycle: diastole PhaseA heartbeat is a two-part pumping action that takes about a second. This part of the two-part pumping phase (the longer of the two) is called diastole.

Diastole begins as the ventricles start to relax. Soon the pressures within the aorta and pulmonary artery exceed ventricular pressures, causing the semilunar valves to close (B2 murmur). As the ventricular pressure falls below the atrial pressure the AV valves open and the ventricles fill with blood. The ventricles fill to about 80% of capacity prior to contraction of the atria, the last event in diastole.

Atrial contraction forces the final 20% of the end-diastolic volume (the volume of blood that exists in the ventricles at the end of diastole) into the ventricles. / SA node contracts

Summary of Diastole:Ventricles relax pulmonary and aortic valves close AV valves open ventricles fill (about 80% of capacity) atria contract (ventricles fill another 20%) / Contraction reaches AV node…

Cardiac Cycle: Systole PhaseThe second part of the pumping phase begins when the ventricles are full of blood. The electrical signals from the SA node travel along a pathway of cells to the ventricles, causing them to contract. This is called systole.

As the ventricles start to contract, the ventricular pressure soon exceeds the atrial pressure, causing the AV valves to close (B1 murmur). As the ventricles continue to contract, the ventricular pressure exceeds the arterial pressures causing the semilunar valves open. Blood is forcefully ejected out of the ventricles and into the aorta and pulmonary artery.

Summary of Systole :ventricles contract AV valves close aortic and pulmonary valves open blood is ejected atria relax and fill with blood

Papillary muscles / Chordae tendineae