The Development of the Heart and Anomalies of the Heart Flashcards
location of heart
in the midline, slightly to the left side of the body
what is the first organ to start functioning in the fetus
the heart
what sides of the heart deals with what
right half = venous blood
left half = arterial blood
pulmonary circulation
push deoxygenated blood to the lungs for oxygentation
systemic circulation
left half to push oxygenated blood to various tissues
4 chambers of the heart
right and left atria: receiving chambers
right and left ventricles: distributing chambers
4 valves of the heart
two atrio ventricular valves: tricuspid and mitral
two semilunar valves: pulmonary and aortic
blood circulation
-right atrium receives venous blood from superior and inferior venacavae
-through tricuspid valve blood goes to right ventricle from the right right atrium
-right ventricle pumps blood into the pulmonary trunk which takes the blood to the lungs for oxygenation
-from the lungs oxygenated blood reaches the left atrium through the pulmonary veins
-through the mitral valve blood from the left atrium goes to the left ventricle
-the left ventricle pumps blood into the aorta which takes to all parts of the body
embryonic heart
heartbeat can be detected at 4th week
heart not fully formed
primordial cardiovascular system consists of
paired endocardial heart tubes
development of the heart
-mainly from the mesoderm and some neural crest cells
-initially cranial to the oropharyngeal membrane
-cranial folding of the embryo brings it to its postnatal location
-lateral folding causes fusion of the right and left endocardial heart tubes to form a single heart tube
heart tube with its chambers
-truncus arteriosis: forms ascending aorta and pulmonary trunk
-conus cordis: absorbed into ventricle to form right and left ventricles
-primitive ventricle
-primitive atria: partioned into right and left atria
-sinus venosus with right and left sinus horns: absorbed into right atrium
differential growth and looping of the heart tube
some parts grow at a faster rate and some grow at a slower rate to allow the atrium to rotate upwards
partitioning of AV canal
-connection between primitive atrium and primitive ventricle
-partioned into right and left sides
-formation of Dorsal and Ventral endocardial cushions which fuse with each other
-fused endocardial cushions divide the AV canal into right and left
interatrial septum
-formation of septum primum: downward growth from roof of primitive atrium
-foramen primum continues right and left parts of primitive atrium
-after fusion of septum primum to endocardial cushions, roof connection is lost giving rise to foramen secundum
-formation of septum secundum: downward growth from primitive atrium
-formation of foramen ovale: gap between floppy septum primum and rigid septum secundum
why do we need the right and left atrium interconnected in the fetus?
lungs are not active yet
foramen ovale
-remains open and connects right atrium with left atrium until birth
-closes after birth
-patent foramen ovale
development of the interventricular system
muscular part: develops as an upward growth from the floor of the primitive ventricular chamber
membranous part: from fusion of the truncal ridges
spiral septum
septation of the outflow tract
-two cono-truncal ridges arise form walls of Truncus arteriosus and fuse to form spiral septum
-cardiac neural crest cells
-triple relationship between aorta and pulmonary trunk retained
cardiac malfunctions
-ventricular septal defects
-atrial septal defects: shunting of blood from RA to LA
-persistence of embryonic structures: persistent foramen ovale, persistent ductus arteriosus
-inadequate oxygenation: cyanosis
persistent truncus arteriosis
-defective division of the outflow tract
-associated with ventricular septal defect
-left to right shunting
fallot’s teratology
-unequal division of the outflow tract, favouring the aorta
1. pulmonary trunk stenosis
2. VSD - ventricular septal defect
3. rightward displacement of aorta
4. right ventricular hypertrophy
transposition of great vessels
-LV pumps blood into the pulmonary trunk and right ventricle into the (aorta) systemic circulation
-can be fatal
dextrocardia
heart juts to the right side because of differential growth flipping
