Cardio FA - Embryo p 278-280 Flashcards
Bulbus Cordis gives rise to?
Smooth parts (outflow tract) of left and right ventricles
Endocardial cushion gives rise to?
Atrial septum, membranous inter ventricular septum, AV and semilunar valves
Left horn of sinus venosus gives rise to?
Coronary sinus
Posterior, sub cardinal, supracardinal vein gives rise to?
IVC
Primitive Atrium gives rise to?
Trabeculated part of left and right atria
Primitive pulmonary vein gives rise to?
Smooth part of left atrium
Primitive ventricle gives rise to?
Trabeculated part of left and right ventricles
Right common cardinal vein and right anterior cardinal vein gives rise to?
SVC
Right horn of sinus venosus gives rise to?
Smooth part of right atrium (sinus venarum)
Truncus arteriosus gives rise to?
Ascending aorta and pulmonary trunk
Primary heart tube loops to establish left and right polarity at what week of gestation?
Week 4
Defect in cardiac looping leads to what?
Defect in left-right Dynein ( involved in L/R asymmetry) can lead to dextrocardia as seen in Kartagener syndrome aka primary ciliary dyskinesia
Septation of chambers in the atria name the 7 steps ? ( sorry for the length)
1-Septum primum grows toward endocardial cushions, narrowing foramen primum. 2-Foramen secundum forms in septum primum (foramen primum disappears). 3-Septum secundum develops as foramen secundum maintains right-to-left shunt. 4-Septum secundum expands and covers most of the foramen secundum. The residual foramen is the foramen ovale. 5-Remaining portion of septum primum forms valve of foramen ovale. 6. (Not shown) Septum secundum and septum primum fuse to form the atrial septum. 7. (Not shown) Foramen ovale usually closes soon after birth because of increased LA pressure and and decreased RA pressure.
What is the cause of Patent Foramen Ovale and what does it lead to?
caused by failure of septum primum and septum secundum to fuse after birth; most are left untreated. Can lead to paradoxical emboli (venous thromboemboli that enter systemic arterial circulation), similar to those resulting from an ASD.
Name the 3 steps for separation of ventricles
1-Muscular interventricular septum forms. Opening is called interventricular foramen. 2-Aortico-pulmonary septum rotates and fuses with muscular ventricular septum to form membranous interventricular septum, closing interventricular foramen. 3- Growth of endocardial cushions separates atria from ventricles and contributes to both atrial septation and membranous portion of the interventricular septum.
Most common congenital cardiac anomaly, usually occurs in membranous septum?
VSD
Outflow tract formation how?
Neural crest and endocardial cell migrations–>>> truncal and bulbar ridges that spiral and fuse to form aorticopulmonary septum —>>> ascending aorta and pulmonary trunk.
Name 3 Conotruncal abnormalities associated with failure of neural crest cells to migrate?
- Transposition ofgreat vessels. • Tetralogy of Fallot. • Persistent truncus arteriosus.
Heart Valves development derived from where?
Aortic/pulmonary: derived from endocardial cushions of outflow tract. Mitral/tricuspid: derived from fused endocardial cushions of the AV canal.
Name a few common valvular anomalies which are commonly seen?
Valvular anomalies may be stenotic, regurgitant, atretic (eg, tricuspid atresia), or displaced (eg, Ebstein anomaly).
Umbilcal vein vs Umbilical Artery ( in terms of differences in O2 saturation)
Blood in umbilical vein has a Po2 of = 30 mm Hg and is = 80% saturated with 0xygen. Umbilical arteries have low 0xygen saturation
Name the 3 important shunts in fetal circulation?
1-) Blood entering fetus th rough the umbilical vein is conducted via the ductus venosus into the IVC, bypassing hepatic circulation. 2-) Most of the highly Oxygenated blood reaching the heart via the IVC is directed through the foramen Ovale and pumped into the aorta to supply the head and body. 3-) Deoxygenated blood from the SVC passes through the RA–>RV–> main pulmonary artery—>Ductus arteriosus—> Descending aorta; shunt is due to high fetal pulmonary artery resistance (due partly to low 0xygen tension).
What happens when baby takes 1st breath?
At birth, infant takes a breath —>decreases resistance in pulmonary vasculature—>>> Leading to increase left atrial pressure vs right atrial pressure—-> foramen ovale closes (now called fossa ovalis); increase in Oxygen (from respiration) and decrease in prostaglandins (from placental separation) - closure of ductus arteriosus.
What closes a PDA?
indomethacin ( PDA becomes ligamentum arteriosum–remnant of PDA)
What keeps PDA open?
PGE1, PGE2
allantois becomes what?
median umbilical ligament
What is the urachus part of and found where?
urachus is part of allantoic duct b/w bladder and umbilicus
postnatal remnant of ductus arteriosus?
ligamentum arteriosum
postnatal remnant of ductus venosus?
ligamentum venosum
postnatal remnant of foramen oval?
fossa ovalis
postnatal remnant of notochord?
nucleus pulposus
postnatal remnant of umbilical arteries?
Medial umbilical ligaments
postnatal remnant of umbilical vein? where is this remnant found?
Ligamentum teres hepatis ( aka round ligament) contained in the faliciform ligament
When does the heart begin to form in embryo?
week 4
What is the tissue of origin of the heart?
Embryonic mesoderm
Embryonic origin of coronary sinus?
left horn of sinus venosus
Causes a harsh holosystolic murmur?
VSD - most common congenital heart anomaly,
Due to failure of neural crest cells to migrate?
Transposition of great vessels Tetralogy of Fallot Persistent truncus arteriosus
What is the O2 saturation of umbilical vein/arteries?
Vein = 80% saturation, A= very low
What is the change in pressure that allows the foramen ovale to close?
At birth, the infant takes a breath - there is a decreased resistance in pulmonary a/v and the LA pressure increases versus the R atrial pressure makes the foramen ovale closes
What process leads to the closure of ductus arteriosus?
Higher levels of O2 from respiration and decrease in prostaglandins due to placental separation lead to closure of ductus arteriosus
Which drug aids in closing PDA? What keeps it open?
Close PDA - Indomethacin Keep PDA open - PGE1; PGE2
With what disease would you want to keep a PDA open?
Transposition of vessels, Pulm atresia
What is the origin of the nucleus pulposus?
notochord
