Cardiovascular- Embryology Flashcards
What does the truncus arteriosis give rise to?
ascending aorta and pulmonary trunk
What does the bulbus cordis give rise to?
smooth parts (outflow tract) of right and left ventricles
What does the primitive atrium give rise to?
trabeculated part of the left and right atria
What does the primitive ventricle give rise to?
trebaculated part of the left and right ventricles
What does the primitive pulmonary vein give rise to?
smooth part of the left atrium
What does the left horn of the sinus venosus give rise to?
coronary sinus
What does the right horn of the sinus venosus give rise to?
smooth part of the right atrium (sinus venarium)
What do the right common cardinal vein and right anterioe cardinal vein give rise to?
SVC
When can a heart beat be heard?
4 weeks
What is cardiac looping?
the primary heart tube loops to establish left-right polarity beginning at week 4 of gestation
NOTE that a defect in left-right dynein can lead to dextrocardia as seen in Kartagener syndrome
What are the first 2 steps in atrial development?
1) the septum primun grows toward the endocardial cushions, narrowing the foramen primum
2) the foramen secundum forms in the septa primum, as the foramen primum dissappears
What are the next steps in atrial development?
3) the septum secundum develops downward and covers most of the foramen secundum, with the residual foramen being the foramen ovale
4) The remaining portion of the septum primum forms the valve of the foramen ovale
What happens to the foramen ovale at birth?
It usually closes due to increasing L.A. pressure
What causes a patent foramen ovale?
failure of the septum primum and septum secundum to fuse after birth
What are the steps of ventricular development?
1) the muscular ventricular septum forms leaving a connection between the two developing ventricles called the interventricular foramen
2) Aorticopulmonary septum rotates and fuses with the muscular ventricular spetum to form the membranous interventricular septum, closing the interventricular foramen
3) growth of endocardial cushions seperate the atria from the ventricles
Ventricular septal defects (VSDs) most commonly occur where?
the membranous septum
What are the aortic and pulmonary valves derived from?
endocardial cushions of the outflow tract
What are the mitral and tricuspid valves derived from?
from fused endocardial cushions of the AV canal
What are the sites of fetal erythropoiesis?
Yolk sac (weeks 3-8)
Liver (week 6- birth)
Spleen (10-28 weeks)
Bone marrow (18 weeks to adult)
What is the primary fetal hemoglobin?
HbF (a2y2)
What is the primary adult hemoglobin?
HbA1 (a2b2)
HbF has higher affinity for O2 binding than adult hemoglobin. Why?
it has less avid binding to 2,3-BPG, allowing HbF to extract O2 from amternal hemoglobin across the placenta
Describe fetal circulation
maternal blood from the placenta is transported to the fetus via the umbilical vein (80% SaO2) where it is shunted from the liver into the IVC via the ductus venosus and into the heart where the majority passes through the foramen ovale and pumped into the aorta
AND
deoxygenated blood from the SVC passes through the right heart into the main pulmonary artery and then into the ductus arteriosus to the descending aorta
How does fetal circulation change at birth?
at the first breath, pulmonary resistance decreases drastically and left atrial pressure increases causing the foramen ovale to close
the increase in O2 and decrease in prostaglandins from palcenta seperation cause the ductus arteriosus to close
What is the remnant of the foreman ovale?
the fossa ovalis
What things can help keep the ductus arteriosis open/patent?
prostaglandins E1 and E2 kEEp it open
What can be used to close a PDA?
Indomethacin
What is the adult remnant of the allantois/urachus?
mediaN umbilical ligament
What is the adult remnant of the ductus arteriosus?
ligamentum arteriosum
What is the adult remnant of the ductus venosus?
ligamentum venosum
What is the adult remnant of the notochord?
the nucleus pulposus
What is the adult remnant of the umbilical arteries?
mediaL umbilical ligaments
What is the adult remnant of the umbilical vein?
ligamentum teres hepatis
The ligamentum teres hepatis is contained in the ________
falciform ligament
