development of the heart and great vessels Flashcards
where do the heart tubes develop from
lateral plate mesoderm of the cranial end of the embryonic germ disc
In 4th week , cephalic and lateral fold of embryonic disc results in fusion to form a angle primitive heart tube
Between week 5-8 the primitive heart tube folds , remodels and septates, reustling in separation of pulmonary and systemic circulation
two shunts in the development of the heart
foramen ovale
ductus arteriosus
what side does the aortic arch normally lie
Right paired dorsal aorta will normally involute so result in left sided aortic arch
Persistence of both primitive arotic results in a vascular ring
Portenilaly constrict both the esophagus and trachea - dysphagia and dyspnoea
The sinus venosus is the most caudal of the primitive heart chambers. By the fourth week (DAY21) of development, it receives blood from the three sets of veins; on each side:
anterior and posterior cardinal veins via the common cardinal vein
umbilical vein
vitelline vein
These veins merge on each side to form the sinus horns which enter the sinus venosus. Cephalically, the sinus venosus is in continuity with the primitive common atrium. The communication between the two is the sinuatrial junction. Folding and enlargement of the heart shift the junction cepahlically and to the right.
the three veins - umbilical, cardinal and vitelline merge to form the sinus horns. Cephalically the sinus venous is a continuation of what
primitive common atrium
cranial to the sinus horns there is the primitive ventricle and the primitive atrium what separates these
atrioventricular sulcus
what does the bulbs cortis ( conus cortis ) form - this is created from the bulboventricular sulcus
truncus arteriosus
aorta and pulmonary trunks
at day 23 which way does the primitive ventricle move and bulbs cordis respectively
Primitive ventricle displaced to the left
bulbs cordis inferiorly to the right
what does the blubus cordis form
primitive right ventricle
what does the conus cordis allow
outflow of tracts of left and right ventricles
what is dextrocardia
heart points toward the right side of your chest instead of the left
gastrulation
what does situs solitus mean
normal position of thoracic and abdominal organs. This means the heart is on the left with the pulmonary atrium on the right and the systemic atrium on the left
situs inversus
congenital(present from birth) condition major visceral organs are reversed or mirrored from their normal positions
levocardia
heart on norma side of the body
what does the sinus venousus from
vena cava receiving blood from the sinus horns
From week five onwards, the following veins are obliterated:
right umbilical
left vitelline
left common cardinal
There is shunting of blood to the right and the the right sinus horn enlarges. Consequently, little remains of the the left sinus horn at birth except the coronary sinus and the oblique vein of the left atrium. Conversely, the dominant right horn assumes the role of the sinus venosus. It becomes incorporated into the wall of the right atrium as its smooth part - the sinus venarum at birth.
The entrance of the sinus venosus into the right atrium is flanked by two folds, the right and left venous valves. Their edges fuse superiorly to form the septum spurium. When fusion of the right horn occurs, the left valve and the septum spurium fuse with the atrial septum. The inferior part of the right valve produces two structures in the mature heart: the valves at the orifice of the inferior vena cava and the orifice of the coronary sinus. The superior part forms the crista terminalis
Umbilical and left vitelline veins obliterate and left cardinal - right sinus horn enlarges and becomes incorporated into atrium( interception) to form smooth wall part called sinus vineerium - opening of the vena cava
Left sinus horn remains small and forms oblique vein of the left atrium and coronary sinus
where do the primitive pulmonary veins develop from
left atrium
Border between right atrium and smooth muscle part is demarcated by ridge called
cristis terminalis
at the end of the 4th week 4 endocardial cushions from dividing atrioventricular canal into right and left atrioventricular orifices from the basis for separation of what two systems
pulmonary and systemic
high pressure In what atrium closes the foramen ovale
Higher pressure in the left atrium resulting from increased pulmonary venous flow from the lungs causes the septum primum of the interatrial septum to close the opening. Over time, the tissue will seal the foramen and become the fossa ovalis.
a patent foramen ovale occurs to failure of fusion of primum and secundum atrial septa leading to flap valve opening
this shunt normally when right atrial pressure exceeds left atrial pressure
what could be a possible consequence ?
paradoxical embolus
atrial septal defect is a deficiency in atrial septum resulting in failure of overlap (hole in the atrial septum) - continuous left to right shunting what problems could this cause
volume loading in right here may increase pulmonary artery pressure and promote arrhythmia.
when does formation the ventricular septum start
end of week 4
muscular interventicualr septum forms closing the foramen
ventriculospetal defect VSD can occur due to failure of formation which is normally diagnosed in children
true
when do the outflow tracts normally form
at week 5
failure of formation of the conotruncal septa result in persistent truncus arterioles - single blood vessel what does this present as
deoxygenated blood
cyanosis in 24hr in babies
At brith pulmonary vascular resistance falls and blood circulates through the lungs
The patents ductus arteriosus normally close forming the ligamentum arteriosum and fossa ovalis respectively
patent ductus arteriosus more common in which gender
females
