FIRST AID FOR NBME QUESTIONS AND 100%CORRECT ANSWERS 2023/2024

FIRST AID FOR NBME QUESTIONS AND 100%CORRECT ANSWERS 2023/2024 Heart Embryological Structures (8)CORRECT ANSWER-Truncus Arteriosus (TA) --> ascending Aorta & Pulmonary Trunk Bulbus Cordis --> Smooth Parts (outflow tract) of L and R Ventricles Primitive Atria --> Trabeculated part of the L and R Atria Primitive Ventricle --> Trabeculated part of the L and R ventricles Primitive Pulmonary Vein --> Smooth part of the L Atrium Left Horn of Sinus Venosus (SV) --> Coronary Sinus Right Horn of SV --> Smooth part of R Atrirum Right Common Cardinal Vein and Right Anterior Cardinal Vein --> SVC Heart Embryological Structures (8)CORRECT ANSWER-Truncus Arteriosus (TA) --> ascending Aorta & Pulmonary Trunk Bulbus Cordis --> Smooth Parts (outflow tract) of L and R Ventricles Primitive Atria --> Trabeculated part of the L and R Atria Primitive Ventricle --> Trabeculated part of the L and R ventricles Primitive Pulmonary Vein --> Smooth part of the L Atrium Left Horn of Sinus Venosus (SV) --> Coronary Sinus Right Horn of SV --> Smooth part of R Atrirum Right Common Cardinal Vein and Right Anterior Cardinal Vein --> SVC Heart MorphogenesisCORRECT ANSWER-First functional organ in vertebrate embryos, beats spontaneously by week 4 Heart MorphogenesisCORRECT ANSWER-First functional organ in vertebrate embryos, beats spontaneously by week 4 Cardiac LoopingCORRECT ANSWER-Primary heart tube loops to establish L/R polarity (begins in gest week 4) Defect in L-R Dynein (involved in L/R asymmetry) can lead to dextrocardia, as seen in Kartagener syndrome (primary ciliary dyskinesia) Cardiac LoopingCORRECT ANSWER-Primary heart tube loops to establish L/R polarity (begins in gest week 4) Defect in L-R Dynein (involved in L/R asymmetry) can lead to dextrocardia, as seen in Kartagener syndrome (primary ciliary dyskinesia) Atrial SeparationCORRECT ANSWER-1. Septum primium 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 R to L shunt 4. Septum secundum expands and covers most of the foramun secundum. Residual foramen is foramen ovale 5. Remaining portion of septum primum forms valve of foramen ovale 6. Septum secundum and septum primum fuse to form atrial septum 7. Foramen ovale usually closes soon after birth because of inc. LA pressure Atrial SeparationCORRECT ANSWER-1. Septum primium 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 R to L shunt 4. Septum secundum expands and covers most of the foramun secundum. Residual foramen is foramen ovale 5. Remaining portion of septum primum forms valve of foramen ovale 6. Septum secundum and septum primum fuse to form atrial septum 7. Foramen ovale usually closes soon after birth because of inc. LA pressure Ventricle SeparatiionCORRECT ANSWER-1. Muscular ventricular septum forms. Opening is called interventricular foramen 2. Aorticopulmunary 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 Ventricle SeparatiionCORRECT ANSWER-1. Muscular ventricular septum forms. Opening is called interventricular foramen 2. Aorticopulmunary 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 Outflow Tract FormationCORRECT ANSWER-Truncus arteriosus rotates; neural crest and endocardial cell migrations --> truncal and bulbar ridges that spiral and fuse to form aorticopulmonary septum --> ascending aorta and pulmonary trunk Conotruncal abnormalities: - Transposition of great vessels - Tetrology of Fallot - Persistent truncus arteriosus Outflow Tract FormationCORRECT ANSWER-Truncus arteriosus rotates; neural crest and endocardial cell migrations --> truncal and bulbar ridges that spiral and fuse to form aorticopulmonary septum --> ascending aorta and pulmonary trunk Conotruncal abnormalities: - Transposition of great vessels - Tetrology of Fallot - Persistent truncus arteriosus Valve DevelopmentCORRECT ANSWER-Aortic/pulmonary: derived from endocardial cushions of outflow tract Mitral/Tricuspid: derived from fused endocardial cushions of the AV canal Valvular anomalies may be stonetic, regurgitant, atretic, or displaced Valve DevelopmentCORRECT ANSWER-Aortic/pulmonary: derived from endocardial cushions of outflow tract Mitral/Tricuspid: derived from fused endocardial cushions of the AV canal Valvular anomalies may be stonetic, regurgitant, atretic, or displaced Fetal ErythropoeisisCORRECT ANSWER-Occurs in: Yolk Sac (3-8 weeks) Liver (6 weeks - birth) Spleen (10-28 weeks) Bone Marrow (18 weeks to adult) Young Liver Synthesizes Blood Fetal ErythropoeisisCORRECT ANSWER-Occurs in: Yolk Sac (3-8 weeks) Liver (6 weeks - birth) Spleen (10-28 weeks) Bone Marrow (18 weeks to adult) Young Liver Synthesizes Blood Hemoglobin DevelopmentCORRECT ANSWER-Fetal Hemoglobin (HbF) = a2y2 Adult Hb = a2b2 HbF has higher affinity due to less avid binding of 2,3 BPG. Allows HbF to extract from mother's HbA Alpha Always, Gamma Goes, Becomes Beta Hemoglobin DevelopmentCORRECT ANSWER-Fetal Hemoglobin (HbF) = a2y2 Adult Hb = a2b2 HbF has higher affinity due to less avid binding of 2,3 BPG. Allows HbF to extract from mother's HbA Alpha Always, Gamma Goes, Becomes Beta Fetal CirculationCORRECT ANSWER-Umbilical Vein PO2 = 30mm Hg, 80% Sat Shunts: 1. Blood entering fetus through umbilical vein is conducted via the ductus venosus into the IVC to bypass hepatic circulation 2. Most highly oxygenated blood reaching heart via IVC is diverted through the foramen ovale and pumped out the aorta to the head and body 3. Deoxygenated blood reentering the RA goes from SVC goes: RA --> RV --> main PA --> Patent Ductus arteriosus --> Descending aorta At birth, infant takes breath --> Dec. resistance in pulmonary vasculature --> inc. L atrial pressure v. R atrial pressure foramen ovale closes (becomes fossa ovalis) inc. in O2 from respiration and dec. in prostaglandins --> closure of ductus arteriosus indomethacin helps close PDA (patent) --> DA remnant (i.e. ligamentum arteriosus) Prostaglandins E1 and E2 keep PDA open Fetal CirculationCORRECT ANSWER-Umbilical Vein PO2 = 30mm Hg, 80% Sat Shunts: 1. Blood entering fetus through umbilical vein is conducted via the ductus venosus into the IVC to bypass hepatic circulation 2. Most highly oxygenated blood reaching heart via IVC is diverted through the foramen ovale and pumped out the aorta to the head and body 3. Deoxygenated blood reentering the RA goes from SVC goes: RA --> RV --> main PA --> Patent Ductus arteriosus --> Descending aorta At birth, infant takes breath --> Dec. resistance in pulmonary vasculature --> inc. L atrial pressure v. R atrial pressure foramen ovale closes (becomes fossa ovalis) inc. in O2 from respiration and dec. in prostaglandins --> closure of ductus arteriosus indomethacin helps close PDA (patent) --> DA remnant (i.e. ligamentum arteriosus) Prostaglandins E1 and E2 keep PDA open Fetal-postnatal DerivativesCORRECT ANSWER-Umbilical Vein --> Ligamentum teres hepatis Umbilical Arteries --> Medial umbilical ligaments Ductus Arteriosus --> Ligamentum arteriosum Ductus Venusus --> Ligamentum venosum Foramen Ovale --> Fossa Ovalis Allantois --> Urachus-median umbilical ligament Notochord --> Nucleus pulposus of intervertebral disc The uranchus is part of the allantoic duct between the bladder and umbilicus. Fetal-postnatal DerivativesCORRECT ANSWER-Umbilical Vein --> Ligamentum teres hepatis