NBME CBSE TERMS AND EXPLANATIONS 2022 A+ MATERIAL
Bulbus cordis - Gives rise to Smooth parts (outflow tract) of left and
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ventricles
Endocardial cushion - Gives rise to atrial septum, membranous interventricular septum; AV and semilunar valves
Left horn of sinus venosus - gives rise to coronary sinus
Posterior, subcardinal, and supracardinal veins - Gives rise to Inferior Vena cava
Primitive atrium - gives rise to trabeculated part of left and right atria
Primitive ventricle - Gives rise to trabeculated parts of LV and RV
Primitive pulmonary vein - Gives Rise to Smooth part of left atrium
Right common cardinal vein and right anterior cardinal vein - Gives rise to Superior vena cava (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
Heart - First functional organ in vertebrate embryos; beats spontaneously by week 4 of development.
Cardiac looping - Primary heart tube loops to establish left-right polarity; begins in week 4 of gestation
Defect in left-right Dynein - involved in L/R asymmetry can lead to Dextrocardia, as seen in Kartagener syndrome(1°ciliary Dyskinesia).
Patent foramen ovale - caused by failure of septum primum and septum secundumto 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
Ventricular septal defect - most common congenital cardiac anomaly, usually occurs in membranous septum.
Septation of atria (7 Steps) - 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 ofLA pressure.
Septation of Ventricle - 1. Muscular interventricular septum forms. Opening is called interventricular foramen
2. Aorticopulmonary 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
Aorticopulmonary septum - rotates and fuses
with muscular ventricular septum to form membranous interventricular septum, closing interventricular foramen
Septum primum - grows toward endocardial cushions, narrowing foramen primum
Foramen secundum - forms in septum primum (foramen primum disappears).
Septum secundum - develops as foramen secundum maintains right-to-left shunt
expands and covers most of the foramen secundum
foramen ovale - connects the two atria in the fetal heart
usually closes soon after birth because of inceased LA pressure and
decreased RA pressure.
Conotruncal abnormalities - associated with failure of neural crest cells to migrate
1.Transposition of great vessels
2.Tetralogy of Fallot.
3.Persistent truncusarteriosus.
Neural crest and endocardial cell migrations - - truncal and bulbar ridges that spiral and fuse to form aorticopulmonary septum -
ascending aorta and pulmonary trunk
Aortic/pulmonary Valve Development - derived from endocardial cushions of outflow tract
Mitral/tricuspid Valve Development - derived from fused endocardial cushions of the AV canal
Valvular anomalies - may be stenotic, regurgitant, atretic (eg, tricuspid atresia), or displaced (eg, Ebstein anomaly).
umbilical vein - blood has a Po2 of 30 mm hg and is 80% saturated w/ O2
Umbilical arteries - have lower O2 saturation than veins in fetus
ductus venosus - Blood entering fetus the rough the
umbilical vein is conducted into the IVC, by passing hepatic circulation.
foramen Ovale - Most of the highly Oxygenated blood reaching the heart via the IVC is directed through and pumped into the aorta to supply the head and body
Ductus arteriosus - a blood vessel in a fetus that bypasses pulmonary circulation by connecting the pulmonary artery directly to the Descending aorta aorta
shunt is due to high fetal pulmonary artery resistance
At birth - infant takes a breath - decreases resistance
in pulmonary vasculature - increases left atrial pressure vs right atrial pressure- foramen ovale doses ; increase in 02 (from respiration) and I in prostaglandins (from placental separation) - closure of ductus arteriosus.
Indomethacin - helps close PDA - ligamentum arteriosum (remnant of ductus arteriosus)
ligamentum arteriosum - remnant of ductus arteriosus
Prostaglandins E1/2 - keep PDA open
Allantois - urachus - Postnatal Derivative: Median umbilical ligament
Urachus - part of allantoic duct between
bladder and umbilicus
Ductus arteriosus - Postnatal Derivative: Ligamentum arteriosum
Near the left recurrent laryngeal nerve.
Ductus venosus - Postnatal Derivative: Ligamentum venosum
Foramen Ovale - Post Natal Derivative: Fossa ovalis
Notochord - Postnatal Derivative: Nucleus pulposus [Show Less]