Anatomy and physiology of the heart
Embryology of normal heart and of the T4F
The congenital heart defects and the T4F
Anatomy and Physiology
of the Heart
Fallot’ Project
http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_anatomy.html
http://www.texasheartinstitute.org/hic/anatomy/anatomy2.cfm
http://www.gwc.maricopa.edu/class/bio202/cyberheart/hartint0.htm
www.biosbcc.net/b100cardio/htm/heartant.htm
The Cardiovascular System
The heart is located between the lungs in the
middle of the chest, behind and slightly to the
left of the breastbone (sternum).
1
Location
1
2
3
2
Heterotaxia
isomerism
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
appendages
Visceral and Heart Situs
Pectinae muscles
Situs solitus
Situs inversus
Right isomerism
Isomérisme
droit
Left Isomerism
Insertions
A 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
back
right
left
front
The Cardiovascular System
Atria / Appendages
right 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 valve
3 leaflets
Chordae tendineae
Papillary muscles
3 chambers
inlet
trabecular part
outlet
The 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 anterocephalad 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.
Specific parts of the right ventricle
Mitrale valve
2 leaflets
anterior
posterior
Left ventricle
Chordae tendineae
2 papillary muscles
anterolateral
posteromedial
3 chambers
inlet
trabecular part
outlet
Left view
The conduction system
The 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.
The 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 Circulation
Coronary sinus
The Heart Valves
A 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 enddiastolic 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: diastole Phase
The 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
Cardiac Cycle: Systole Phase
Papillary muscles / Chordae tendineae