Heart Development Flashcards
Truncus arteriosus
blood out top of developing heart
one artery - develops into aorta and pulmonary trunk
continuous with aortic sac
Bulbus cordis
outflow part of ventricles, before semilunar valves
becomes conus arteriosus and aortic vestibule leading to valves
proximal to truncus arteriosus
Sinus venosus
blood in, bottom
recieves blood from vitelline, umbilical, and cardinal vv.
Develops into right and left horns
vitelline v.
drains yolk sac
umbilical v.
from mom
cardinal v.
early v. of embryonic body
Bulboventricular loop
bend between inflow and outflow parts
causes atrium and sinus venosus to come to lie dorsal
Semilunar valves develop from
3 swellings of subendocardial tissue
restructred into cusps
AV valves develop from
proliferation of endocardial cushions - cardiac jelly - around AV canals
Septum Primum
first septum between atriums
closes Foramen primum - opening
Foramen Secondum
opens in septum primum to allow flow between atriums
Septum secundum
2nd wall, crescent shaped
Overlaps foramen secondum
Foramen Ovale
opening in septum secundum
Forms a flap valve with septum primum between atrium
Fossa Ovalis
after birth two septums fuse, causing fossa ovalis
membrane of fossa ovalis (over old foramen ovale) is from septum primum
border of fossa ovalis is from septum secundum
only seen in RA
Right horn of sinus venosus
becomes posterior wall of right atrium - sinus venarum
Atrial septal defects
No overlap in septum between atriums
Secundum - occurs in area of oval fossa (defects in either or both septums)
Endocardial cushion - defect in septum primum (doesn’t fuse with endocardial cushions)
Sinus venosus - incomplete absorption of sinus venosus into RA, abnormal development of septum secundum or both
Common atrium - all three types of defects
Ventricular septal defects
Membranous - membranous IV septum doesn’t close
Muscular - muscular septum doesn’t close at some point
Abnormal division of truncus arteriosus
Persistent truncus arteriosus - aorta and pulmonary trunk don’t separate (failure of truncal ridges and aorticopulmonary septum to develop) - single arterial trunk
Pulmonary stenosis
cusps of pulmonary valve fused together with a narrow opening
obstruct blood flow
Tetralgy of Fallot
Pulmonary stenosis - obstructed right ventricular outflow
VSD
Overriding aorta
Right ventricular hypertrophy
1st pharyngeal arch a.
largely disappears
forms parts of maxillary arteries
2nd pharyngeal arch a.
stapedial arteries
3rd pharyngeal arch a.
form common carotid arteries
4th pharyngeal arch a.
part of aortic arch
right subclavian a.
5th pharyngeal arch a.
disappears
6th pharyngeal arch a.
pulmonary arteries
ductus arteriosus - becomes ligamentum arteriosum (between pulmonary artery and aorta)
