DIT Step 1 Cardio Study Guide Questions with 100% Verified Answers 2026

DIT Step 1 Cardio Study Guide Questions with 100% Verified Answers 2026 septum primum obliterates what? - Correct Answer ostium primum what divides the left and right atria in embryology? - Correct Answer septum primum and primum secundum How is blood shunted from R to L in embryo? - Correct Answer Foramen ovale (in septum secundum), and ostium secundum (in septum primum) What syndrome increases risk for endocardial cushion defects - Correct Answer Trisomy 21 Cells of spiral septum derive from what? - Correct Answer neural crest cells Truncus arteriosus becomes what structures? - Correct Answer proximal aorta and pulmonary trunk Primitive ventricle becomes what structures - Correct Answer ventricles bulbus cordis becomes what structures? - Correct Answer ventricular outflow tracts Left horn sinus venosus becomes what structure? R horn? - Correct Answer L horn: coronary sinus R horn: smooth portion of R atrium Aortic arches derive into what? 1st, 2nd, 3rd, 4th, 6th - Correct Answer 1. part of maxillary artery 2. stapedial and hyoid artery