front 1 A newborn with abnormal myocardial development has disrupted formation of the primitive heart muscle layer. Which embryologic source most directly forms the myocardium? A) Neural crest ectoderm B) Paraxial mesoderm C) Splanchnic mesoderm D) Surface ectoderm | back 1 C. Splanchnic mesoderm |
front 2 During early heart tube formation, an endothelial-lined structure differentiates into the inner lining of the heart. Which pairing is most accurate? A) Endothelial tube—endocardium B) Neural crest—myocardium C) Splanchnic mesoderm—epicardium D) Aortic sac—pericardium | back 2 A. Endothelial tube—endocardium |
front 3 A mutation disrupts the embryonic endothelial tube during cardiogenesis. Which mature cardiac layer is most directly affected? A) Epicardium B) Myocardium C) Endocardium D) Fibrous pericardium | back 3 C. Endocardium |
front 4 A pathology specimen shows abnormal visceral pericardial development. Which alternate name and cellular origin are correctly paired? A) Endocardium—endothelial cells B) Epicardium—mesothelial cells C) Myocardium—neural crest cells D) Pericardium—splanchnic cells | back 4 B. Epicardium—mesothelial cells |
front 5 Visceral pericardial mesothelial cells fail to migrate from their normal embryologic source. Which source is most implicated? A) Sinus venosus B) Aortic sac C) Pharyngeal arches D) Oropharyngeal membrane | back 5 A. Sinus venosus |
front 6 During cephalocaudal folding, the primitive heart changes position relative to foregut and oropharyngeal membrane. Which relationship is correct? A) Dorsal foregut, cranial membrane B) Ventral foregut, caudal membrane C) Dorsal foregut, caudal membrane D) Ventral foregut, cranial membrane | back 6 B. Ventral foregut, caudal membrane |
front 7 A developmental anomaly places the primitive heart dorsal to the foregut after head folding. Which normal relationship has failed? A) Heart ventral to foregut B) Heart cranial to foregut C) Heart dorsal to foregut D) Heart lateral to foregut | back 7 A. Heart ventral to foregut |
front 8 After head folding, which positional relationship normally describes the heart relative to the oropharyngeal membrane? A) Dorsal B) Lateral C) Cranial D) Caudal | back 8 D. Caudal |
front 9 A researcher labels all structures derived from the embryonic bulbus cordis region. Which set matches the provided components? A) Atrium, ventricle, sinus venosus B) Truncus, conus arteriosus, conus cordis C) Aortic sac, atrium, vitelline vein D) SA valve, AV canal, ventricle | back 9 B. Truncus, conus arteriosus, conus cordis |
front 10 Which embryonic structure is listed as a component of the bulbus cordis? A) Common cardinal vein B) Primordial atrium C) Truncus arteriosus D) Transverse sinus | back 10 C. Truncus arteriosus |
front 11 A defect affects the outflow region continuous with the aortic sac. Which embryonic structure is directly continuous with it? A) Sinus venosus B) Truncus arteriosus C) Primordial atrium D) Atrioventricular canal | back 11 B. Truncus arteriosus |
front 12 Which continuity best describes early cardiac outflow anatomy? A) Sinus venosus—aortic sac B) AV canal—pharyngeal arch C) Truncus arteriosus—aortic sac D) Primordial atrium—bulbus cordis | back 12 C. Truncus arteriosus—aortic sac |
front 13 A lineage-tracing experiment marks progenitors that populate both inflow and outflow poles of the developing heart. Which embryonic field is labeled? A) First pharyngeal arch B) Second heart field C) Neural crest field D) Left-heart field | back 13 B. Second heart field |
front 14 Second heart field progenitor cells contribute most directly to which regions of the developing heart? A) Only atrioventricular cushions B) Only ventricular trabeculae C) Arterial and venous ends D) Pericardial and pleural cavities | back 14 C. Arterial and venous ends |
front 15 A venous inflow abnormality disrupts channels entering the sinus venosus. Which triplet normally drains into the sinus venosus? A) Pulmonary, hepatic, renal veins B) Umbilical, vitelline, cardinal veins C) Aortic, pharyngeal, carotid arteries D) Jugular, subclavian, iliac veins | back 15 B. Umbilical, vitelline, cardinal veins |
front 16 Which vessel-source pairing entering the sinus venosus is correct? A) Umbilical vein—chorion B) Vitelline vein—embryo C) Cardinal vein—umbilical vesicle D) Pulmonary vein—placenta | back 16 A. Umbilical vein—chorion |
front 17 Which vessel-source pairing correctly describes sinus venosus inflow? A) Cardinal vein—chorion B) Umbilical vein—embryo C) Vitelline vein—umbilical vesicle D) Pulmonary vein—umbilical vesicle | back 17 C. Vitelline vein—umbilical vesicle |
front 18 A mapping study follows veins returning blood from the embryo proper into the sinus venosus. Which vein is being traced? A) Umbilical vein B) Vitelline vein C) Pulmonary vein D) Common cardinal vein | back 18 D. Common cardinal vein |
front 19 Which sinus venosus inflow set is fully matched to its source? A) Umbilical-chorion, vitelline-vesicle, cardinal-embryo B) Umbilical-embryo, vitelline-chorion, cardinal-vesicle C) Umbilical-vesicle, vitelline-embryo, cardinal-chorion D) Umbilical-placenta, vitelline-embryo, cardinal-foregut | back 19 A. Umbilical-chorion, vitelline-vesicle, cardinal-embryo |
front 20 A 4-week embryo has abnormal cardiac looping. Normal tubular heart looping occurs during which developmental window? A) Days 12–16 B) Days 17–22 C) Days 23–28 D) Days 35–42 | back 20 C. Days 23–28 |
front 21 A cardiac looping defect causes abnormal right-left positioning of primitive chambers. Which normal looping direction is expected? A) Sinistral looping B) Dextral looping C) Ventral looping D) Dorsal looping | back 21 B. Dextral looping |
front 22 During days 23–28, the heart tube bends to establish normal chamber relationships. What loop normally forms? A) Sinuatrial loop B) Bulboventricular loop C) Atrioventricular loop D) Pharyngeal arch loop | back 22 B. Bulboventricular loop |
front 23 Which pairing best describes normal early heart tube looping? A) Dextral, days 23–28 B) Sinistral, days 23–28 C) Dextral, days 35–42 D) Sinistral, days 17–22 | back 23 A. Dextral, days 23–28 |
front 24 Before heart tube formation, asymmetric gene expression helps establish cardiac laterality. Which transcription factor is expressed in the left-heart forming field? A) NKX2-5 B) TBX5 C) Pitx2c D) GATA4 | back 24 C. Pitx2c |
front 25 A mutation disrupts Pitx2c expression before heart tube formation. Which developmental process is most directly affected? A) Left-right heart patterning B) Myocardial calcium cycling C) Endocardial tube apoptosis D) Epicardial mesothelial migration | back 25 A. Left-right heart patterning |
front 26 Which pairing best connects Pitx2c with its embryologic role? A) Pitx2c—left-right patterning B) Pitx2c—SA valve formation C) Pitx2c—pericardial closure D) Pitx2c—phosphate transport | back 26 A. Pitx2c—left-right patterning |
front 27 During primordial heart bending, which structures normally lie dorsal to the truncus arteriosus, bulbus cordis, and ventricles? A) Aortic sac and arches B) Atrium and sinus venosus C) Foregut and oropharyngeal membrane D) Endocardium and myocardium | back 27 B. Atrium and sinus venosus |
front 28 Which spatial relationship is established as the primordial heart bends? A) Atrium dorsal to ventricles B) Ventricle dorsal to atrium C) Truncus dorsal to sinus venosus D) Bulbus dorsal to atrium | back 28 A. Atrium dorsal to ventricles |
front 29 A teratogen disrupts signaling pathways required for cardiac looping. Which set contains the relevant signaling molecules? A) FGF, VEGF, EGF, TGF B) BMP, Notch, Wnt, SHH C) PTH, ADH, ANP, BNP D) RAAS, insulin, glucagon, cortisol | back 29 B. BMP, Notch, Wnt, SHH |
front 30 Which signaling molecule is included among cardiac looping regulators? A) SHH B) PTH C) ANP D) ADH | back 30 A. SHH |
front 31 Which signaling combination is most associated with cardiac looping? A) BMP and Notch B) Insulin and glucagon C) Aldosterone and renin D) Estrogen and progesterone | back 31 A. BMP and Notch |
front 32 During heart development, a pericardial cavity communication forms between both sides around the arterial and venous poles. Which structure is this? A) Atrioventricular canal B) Transverse pericardial sinus C) Sinus venosus D) Pharyngeal arch artery | back 32 B. Transverse pericardial sinus |
front 33 The transverse pericardial sinus represents communication between which spaces? A) Right and left pericardial cavities B) Atrial and ventricular cavities C) Pleural and peritoneal cavities D) Foregut and pharyngeal cavities | back 33 A. Right and left pericardial cavities |
front 34 By the end of the fourth week, the embryonic heart has achieved which functional pattern? A) Random contraction, bidirectional flow B) Coordinate contraction, unidirectional flow C) Coordinate contraction, bidirectional flow D) Random contraction, unidirectional flow | back 34 B. Coordinate contraction, unidirectional flow |
front 35 A sonographic study at the end of week 4 evaluates early cardiac function. Which finding is expected? A) Uncoordinated flow only B) Coordinated bidirectional flow C) Coordinated unidirectional flow D) Silent myocardial tube | back 35 C. Coordinated unidirectional flow |
front 36 Which source-to-sinus venosus drainage pairing is correct? A) Embryo—common cardinal veins B) Placenta—vitelline veins C) Umbilical vesicle—cardinal veins D) Chorion—pulmonary veins | back 36 A. Embryo—common cardinal veins |
front 37 Venous drainage from the placenta reaches the sinus venosus through which veins? A) Vitelline veins B) Common cardinal veins C) Umbilical veins D) Pulmonary veins | back 37 C. Umbilical veins |
front 38 Venous drainage from the umbilical vesicle reaches the sinus venosus through which veins? A) Common cardinal veins B) Umbilical veins C) Vitelline veins D) Anterior cardinal veins | back 38 C. Vitelline veins |
front 39 Which complete venous drainage set enters the sinus venosus? A) Cardinal-embryo, umbilical-placenta, vitelline-vesicle B) Cardinal-placenta, umbilical-embryo, vitelline-vesicle C) Cardinal-vesicle, umbilical-placenta, vitelline-embryo D) Cardinal-embryo, umbilical-vesicle, vitelline-placenta | back 39 A. Cardinal-embryo, umbilical-placenta, vitelline-vesicle |
front 40 Blood entering the sinus venosus next passes into which chamber, through which regulating structures? A) Primordial atrium, SA valves B) Primordial ventricle, AV valves C) Bulbus cordis, semilunar valves D) Aortic sac, truncal valves | back 40 A. Primordial atrium, SA valves |
front 41 Which sequence correctly describes inflow from the sinus venosus to the primitive ventricle? A) Sinus, atrium, AV canal, ventricle B) Sinus, ventricle, AV canal, atrium C) Atrium, sinus, AV canal, ventricle D) Sinus, AV canal, atrium, ventricle | back 41 A. Sinus, atrium, AV canal, ventricle |
front 42 After blood enters the primordial atrium, it reaches the primordial ventricle through which structure? A) Aortic sac B) Sinuatrial valve C) Atrioventricular canal D) Truncus arteriosus | back 42 C. Atrioventricular canal |
front 43 Which embryonic valves regulate blood flow from the sinus venosus into the primordial atrium? A) Semilunar valves B) Sinuatrial valves C) Atrioventricular valves D) Spiral valves | back 43 B. Sinuatrial valves |
front 44 Blood pumped from the primordial ventricle travels through which immediate outflow structure? A) Sinus venosus B) Atrioventricular canal C) Bulbus cordis D) Primordial atrium | back 44 C. Bulbus cordis |
front 45 Which outflow sequence correctly follows blood pumped from the primordial ventricle? A) Bulbus, aortic sac, arch arteries B) Aortic sac, bulbus, arch arteries C) Arch arteries, bulbus, aortic sac D) Bulbus, atrium, arch arteries | back 45 A. Bulbus, aortic sac, arch arteries |
front 46 A developmental diagram traces blood from the primordial ventricle to systemic embryonic outflow. Which final vascular destination is reached after the aortic sac? A) Umbilical veins B) Common cardinal veins C) Pharyngeal arch arteries D) Sinus venosus | back 46 C. Pharyngeal arch arteries |
front 47 Which paired embryonic blood-flow relationship is correct? A) Sinus venosus to atrium B) Atrium to aortic sac C) Ventricle to sinus venosus D) Bulbus cordis to AV canal | back 47 A. Sinus venosus to atrium |
front 48 Which comparison of primitive inflow and outflow is most accurate? A) Inflow uses sinus venosus B) Inflow begins at bulbus cordis C) Outflow ends at sinus venosus D) Outflow bypasses aortic sac | back 48 A. Inflow uses sinus venosus |
front 49 A 5-week embryo begins forming separate cardiac chambers. During which interval does partitioning of the primordial heart normally occur? A) Weeks 2–4 B) Weeks 3–6 C) Weeks 4–8 D) Weeks 6–10 | back 49 C. Weeks 4–8 |
front 50 A congenital heart defect is traced to abnormal early cardiac partitioning. Which developmental timing best matches this process? A) Starts week 4, ends week 8 B) Starts week 5, ends week 7 C) Starts week 6, ends week 10 D) Starts week 3, ends week 5 | back 50 A. Starts week 4, ends week 8 |
front 51 A researcher studies the extracellular matrix precursor that gives rise to AV endocardial cushions. Which source is most directly involved? A) Neural crest B) Cardiac jelly C) Septum secundum D) Sinus venosus | back 51 B. Cardiac jelly |
front 52 A mutation disrupts formation of AV endocardial cushions. Which embryonic material normally develops into these cushions? A) Cardiac jelly B) Epicardial mesothelium C) Truncal ridges D) Primitive myocardium | back 52 A. Cardiac jelly |
front 53 During the 5th week, AV endocardial cushions approach each other. What is the main anatomic result? A) Closure of foramen ovale B) Division of AV canal C) Formation of coronary sinus D) Expansion of left horn | back 53 B. Division of AV canal |
front 54 The AV canal fails to divide normally during the 5th week. Which embryologic structures most likely failed to approximate? A) Bulbar ridges B) Septum secundum folds C) AV endocardial cushions D) Pulmonary vein buds | back 54 C. AV endocardial cushions |
front 55 Mesenchymal transformation of AV cushions contributes directly to which mature cardiac structures? A) Valves and membranous septa B) Trabeculae and coronary arteries C) Epicardium and myocardium D) Semilunar valves only | back 55 A. Valves and membranous septa |
front 56 A neonate has defects involving membranous septa and valves. Abnormal transformation of which embryonic structure best explains both findings? A) Sinus venosus B) AV endocardial cushions C) Septum primum D) Primordial pulmonary vein | back 56 B. AV endocardial cushions |
front 57 Which cell type transforms the AV cushions before they contribute to valves and membranous septa? A) Endothelial cells B) Mesenchymal cells C) Neural crest cells D) Myocardial cells | back 57 B. Mesenchymal cells |
front 58 Which set contains signaling factors involved in AV endocardial cushion cell transformation? A) PTH, ADH, ANP, BNP B) TGF-β1, TGF-β2, BMP-2A, BMP-4 C) Pitx2c, Wnt, SHH, Notch D) VEGF, FGF, EGF, PDGF | back 58 B. TGF-β1, TGF-β2, BMP-2A, BMP-4 |
front 59 A gene expression study of AV cushion transformation detects transcriptional regulators and signaling molecules. Which molecule belongs in this process? A) Slug B) Troponin C) Myosin D) Elastin | back 59 A. Slug |
front 60 Which combination best matches AV cushion transformation factors? A) Slug and ChALK2 B) Renin and ACE C) Pitx2c and SHH D) NKX2-5 and TBX5 | back 60 A. Slug and ChALK2 |
front 61 Which pair of septa contributes to mature interatrial septum formation? A) Septum primum and secundum B) Bulbar ridge and truncal ridge C) Crista terminalis and SA valve D) Endocardial cushion and conus cordis | back 61 A. Septum primum and secundum |
front 62 A fetal echocardiogram shows abnormal interatrial septation. Which embryonic septa normally form the mature interatrial septum? A) Bulbar and truncal septa B) Primum and secundum septa C) Membranous and muscular septa D) Right and left SA valves | back 62 B. Primum and secundum septa |
front 63 Foramen primum and foramen secundum develop within which embryonic structure? A) Septum secundum B) Endocardial cushion C) Septum primum D) Sinus venosus | back 63 C. Septum primum |
front 64 A defect specifically prevents formation of both foramen primum and foramen secundum. Which septal structure is most affected? A) Septum primum B) Septum secundum C) Bulbar ridge D) Crista terminalis | back 64 A. Septum primum |
front 65 Septum secundum growth occurs during which developmental window? A) Weeks 3–4 B) Weeks 5–6 C) Weeks 7–8 D) Weeks 9–10 | back 65 B. Weeks 5–6 |
front 66 A 6-week embryo is undergoing interatrial septation. Which structure should be actively growing at this time? A) Septum secundum B) Coronary sinus C) Crista terminalis D) Primordial pulmonary vein | back 66 A. Septum secundum |
front 67 Before birth, atrial blood normally shunts in which direction? A) Left to right B) Right to left C) Ventricle to atrium D) Pulmonary to systemic | back 67 B. Right to left |
front 68 A fetal circulation question asks why oxygenated placental blood bypasses the lungs. Which atrial flow pattern is normal before birth? A) Right atrium to left atrium B) Left atrium to right atrium C) Left ventricle to right atrium D) Pulmonary trunk to aorta | back 68 A. Right atrium to left atrium |
front 69 The sinus venosus initially opens into which location? A) Ventral right ventricle B) Dorsal primordial atrium C) Left atrial appendage D) Caudal truncus arteriosus | back 69 B. Dorsal primordial atrium |
front 70 A developmental model traces early venous inflow into the primitive heart. The sinus venosus first opens into the dorsal wall of which chamber? A) Primordial atrium B) Primordial ventricle C) Bulbus cordis D) Aortic sac | back 70 A. Primordial atrium |
front 71 Two left-to-right shunts enlarge the right horn of the sinus venosus. Which process is one contributor? A) Pulmonary vein regression B) Vitelline-umbilical transformation C) Septum primum apoptosis D) Bulbar ridge fusion | back 71 B. Vitelline-umbilical transformation |
front 72 Which second process helps enlarge the right horn of the sinus venosus through left-to-right shunting? A) Anterior cardinal anastomosis B) Posterior cardinal apoptosis C) Pulmonary venous separation D) AV canal obliteration | back 72 A. Anterior cardinal anastomosis |
front 73 Which pair of events enlarges the right sinus horn? A) Vitelline-umbilical transformation, anterior cardinal anastomosis B) Pulmonary vein fusion, septum primum growth C) Bulbar ridge fusion, AV cushion regression D) Coronary sinus enlargement, left SA fusion | back 73 A. Vitelline-umbilical transformation, anterior cardinal anastomosis |
front 74 The superior vena cava is derived from which venous system? A) Vitelline veins B) Umbilical veins C) Cardinal veins D) Pulmonary veins | back 74 C. Cardinal veins |
front 75 A congenital venous anomaly affects the embryologic precursor of the superior vena cava. Which embryonic veins are implicated? A) Cardinal veins B) Vitelline veins C) Umbilical veins D) Hepatic veins | back 75 A. Cardinal veins |
front 76 The left horn of the sinus venosus normally becomes which mature structure? A) Smooth right atrium B) Coronary sinus C) Superior vena cava D) Left atrial wall | back 76 B. Coronary sinus |
front 77 The right horn of the sinus venosus normally contributes to which adult heart region? A) Smooth right atrium B) Trabeculated left atrium C) Coronary sinus D) Pulmonary venous wall | back 77 A. Smooth right atrium |
front 78 Which sinus venosus derivative pairing is correct? A) Left horn—coronary sinus B) Left horn—smooth right atrium C) Right horn—coronary sinus D) Right horn—left atrium | back 78 A. Left horn—coronary sinus |
front 79 A pathology specimen identifies the smooth-walled portion of the right atrium. Which embryonic structure primarily forms it? A) Left sinus horn B) Septum primum C) Right sinus horn D) Bulbus cordis | back 79 C. Right sinus horn |
front 80 The cranial part of the right sinuatrial valve is represented by which adult structure? A) Crista terminalis B) Valve of IVC C) Valve of coronary sinus D) Fossa ovalis | back 80 A. Crista terminalis |
front 81 The caudal part of the sinuatrial valve forms which adult structures? A) Mitral and tricuspid valves B) IVC and coronary sinus valves C) Aortic and pulmonary valves D) AV and semilunar valves | back 81 B. IVC and coronary sinus valves |
front 82 Which embryologic pairing is accurate for the right SA valve? A) Cranial part—crista terminalis B) Cranial part—IVC valve C) Caudal part—septum secundum D) Caudal part—left atrium | back 82 A. Cranial part—crista terminalis |
front 83 The left sinuatrial valve normally fuses with which developing septal structure? A) Septum primum B) Septum secundum C) Bulbar ridge D) Endocardial cushion | back 83 B. Septum secundum |
front 84 A defect prevents normal fusion of the left SA valve. Which structure does it normally fuse with? A) Septum secundum B) Septum primum C) Crista terminalis D) Coronary sinus | back 84 A. Septum secundum |
front 85 The primordial pulmonary vein contributes directly to formation of which chamber? A) Right atrium B) Right ventricle C) Left atrium D) Left ventricle | back 85 C. Left atrium |
front 86 A newborn has pulmonary veins that fail to connect with the left atrium. What is this condition called? A) Tricuspid atresia B) TAPVR C) Tetralogy of Fallot D) Ebstein anomaly | back 86 B. TAPVR |
front 87 Which embryologic failure defines total anomalous pulmonary venous return? A) Pulmonary veins miss left atrium B) Cardinal veins miss right atrium C) AV cushions fail division D) Bulbar ridges fail looping | back 87 A. Pulmonary veins miss left atrium |
front 88 Closure of the interventricular foramen normally occurs by the end of which week? A) Week 5 B) Week 6 C) Week 7 D) Week 8 | back 88 C. Week 7 |
front 89 The interventricular foramen closes when which structures fuse? A) Septum primum and secundum B) Bulbar ridges and endocardial cushion C) SA valve and crista terminalis D) Pulmonary vein and left atrium | back 89 B. Bulbar ridges and endocardial cushion |
front 90 A fetus has persistent interventricular communication after week 7. Failure of which fusion best explains this? A) Bulbar ridges with cushion B) Septum secundum with valve C) Pulmonary vein with atrium D) Cardinal veins with SVC | back 90 A. Bulbar ridges with cushion |
front 91 The membranous interventricular septum is derived from which embryonic region? A) Left endocardial cushion B) Right endocardial cushion C) Septum secundum D) Right sinus horn | back 91 B. Right endocardial cushion |
front 92 A ventricular septal defect involves the membranous septum. Which embryologic source is most relevant? A) Right endocardial cushion B) Left sinus horn C) Septum primum D) Primordial pulmonary vein | back 92 A. Right endocardial cushion |
front 93 After closure of the interventricular foramen and membranous septum formation, which structures can communicate properly? A) Left atrium and coronary sinus B) Right ventricle and pulmonary trunk C) Right atrium and left atrium D) Left ventricle and sinus venosus | back 93 B. Right ventricle and pulmonary trunk |
front 94 Which developmental event allows the right ventricle to communicate with the pulmonary trunk? A) Interventricular foramen closure B) Septum primum perforation C) Left horn regression D) Cardinal vein anastomosis | back 94 A. Interventricular foramen closure |
front 95 Routine fetal cardiac screening is first performed during which gestational window? A) 10–14 weeks B) 14–18 weeks C) 18–22 weeks D) 24–28 weeks | back 95 C. 18–22 weeks |
front 96 A pregnant patient asks when fetal cardiac screening is first typically performed. Which timing is most appropriate? A) 8–12 weeks B) 12–16 weeks C) 18–22 weeks D) 28–32 weeks | back 96 C. 18–22 weeks |
front 97 Active mesenchymal proliferation in the bulbus cordis occurs during which week and forms which structure? A) Week 4, septum primum B) Week 5, bulbar ridges C) Week 6, coronary sinus D) Week 7, pulmonary veins | back 97 B. Week 5, bulbar ridges |
front 98 A developmental defect prevents bulbar ridge formation. Which embryonic process most directly failed? A) Mesenchymal proliferation in bulbus cordis B) Mesothelial migration from sinus venosus C) Pulmonary venous incorporation D) Septum secundum apoptosis | back 98 A. Mesenchymal proliferation in bulbus cordis |
front 99 Which timing-structure pairing best matches bulbus cordis development? A) Week 5—bulbar ridges B) Week 6—septum primum C) Week 7—left sinus horn D) Week 8—cardiac jelly | back 99 A. Week 5—bulbar ridges |
front 100 During normal cardiac septation, when does partitioning of the primordial heart begin and end? A) Weeks 2–6 B) Weeks 3–7 C) Weeks 4–8 D) Weeks 5–9 | back 100 C. Weeks 4–8 |
front 101 A 5-week embryo has failed division of the atrioventricular canal. Which source and event are normally involved? A) Cardiac jelly; AV cushions meet B) Neural crest; bulbar ridges fuse C) Sinus venosus; SA valves fuse D) Pulmonary vein; atrium forms | back 101 A. Cardiac jelly; AV cushions meet |
front 102 AV cushions undergo mesenchymal transformation during heart development. Which mature structures do they help form? A) Atria and coronary sinus B) Myocardium and epicardium C) Pulmonary veins and SVC D) Valves and membranous septa | back 102 D. Valves and membranous septa |
front 103 Which set contains factors involved in AV endocardial cushion transformation? A) Pitx2c, Wnt, SHH, Notch B) TGF-β1/2, BMP-2A/4, Slug, ChALK2 C) PTH, ADH, ANP, aldosterone D) VEGF, FGF, EGF, renin | back 103 B. TGF-β1/2, BMP-2A/4, Slug, ChALK2 |
front 104 Which septa contribute to the mature interatrial septum? A) Septum primum and secundum B) Bulbar and truncal ridges C) Right and left SA valves D) Muscular and membranous septa | back 104 A. Septum primum and secundum |
front 105 Foramen primum and foramen secundum form in which structure? A) Septum secundum B) Endocardial cushion C) Bulbar ridge D) Septum primum | back 105 D. Septum primum |
front 106 Septum secundum normally grows during which developmental window? A) Weeks 3–4 B) Weeks 4–5 C) Weeks 5–6 D) Weeks 7–8 | back 106 C. Weeks 5–6 |
front 107 Before birth, normal atrial blood flow occurs in which direction? A) Left to right B) Right to left C) Ventricle to atrium D) Pulmonary to systemic | back 107 B. Right to left |
front 108 The sinus venosus initially opens into which embryonic heart region? A) Dorsal primordial atrium B) Ventral primordial ventricle C) Cranial bulbus cordis D) Caudal aortic sac | back 108 A. Dorsal primordial atrium |
front 109 Which two left-to-right shunts enlarge the right horn of the sinus venosus? A) Pulmonary incorporation; septal perforation B) Bulbar fusion; cushion migration C) Cardinal regression; venous apoptosis D) Vitelline-umbilical transformation; cardinal anastomosis | back 109 D. Vitelline-umbilical transformation; cardinal anastomosis |
front 110 Which embryonic veins give rise to the superior vena cava? A) Umbilical veins B) Cardinal veins C) Vitelline veins D) Pulmonary veins | back 110 B. Cardinal veins |
front 111 Which sinus venosus derivative pairing is correct? A) Left horn—smooth right atrium B) Right horn—coronary sinus C) Left horn—coronary sinus D) Right horn—left atrium | back 111 C. Left horn—coronary sinus |
front 112 The smooth part of the right atrium is derived from which structure? A) Right sinus horn B) Left sinus horn C) Septum primum D) Pulmonary vein | back 112 A. Right sinus horn |
front 113 Which right SA valve derivative pairing is correct? A) Cranial—IVC valve B) Caudal—crista terminalis C) Cranial—coronary sinus valve D) Cranial—crista terminalis | back 113 D. Cranial—crista terminalis |
front 114 The caudal part of the SA valve forms which adult valves? A) Mitral and tricuspid valves B) IVC and coronary sinus valves C) Aortic and pulmonary valves D) Pulmonary and venous valves | back 114 B. IVC and coronary sinus valves |
front 115 The left SA valve normally fuses with which structure? A) Septum primum B) Endocardial cushion C) Septum secundum D) Bulbar ridge | back 115 C. Septum secundum |
front 116 Which embryonic structure forms the left atrium? A) Primordial pulmonary vein B) Right sinus horn C) Left sinus horn D) Common cardinal vein | back 116 A. Primordial pulmonary vein |
front 117 Failure of pulmonary veins to connect with the left atrium causes which anomaly? A) Tricuspid atresia B) Ebstein anomaly C) Tetralogy of Fallot D) TAPVR | back 117 D. TAPVR |
front 118 Closure of the interventricular foramen normally occurs when which structures fuse by week 7? A) Septum primum and secundum B) Bulbar ridges and cushion C) SA valve and septum secundum D) Pulmonary vein and atrium | back 118 B. Bulbar ridges and cushion |
front 119 The membranous interventricular septum derives from which embryonic structure? A) Left sinus horn B) Septum primum C) Right endocardial cushion D) Primordial pulmonary vein | back 119 C. Right endocardial cushion |
front 120 After interventricular foramen closure and membranous septum formation, which structures communicate? A) Right ventricle and pulmonary trunk B) Left atrium and coronary sinus C) Right atrium and left atrium D) Left ventricle and sinus venosus | back 120 A. Right ventricle and pulmonary trunk |
front 121 Initial fetal cardiac screening is typically performed during which gestational window? A) 10–14 weeks B) 14–18 weeks C) 24–28 weeks D) 18–22 weeks | back 121 D. 18–22 weeks |
front 122 Active mesenchymal proliferation in the bulbus cordis occurs during week 5 and forms what? A) Septum secundum B) Bulbar ridges C) Coronary sinus D) AV canal | back 122 B. Bulbar ridges |
front 123 A newborn has complete absence of the interatrial septum. Which congenital defect does this describe? A) Common atrium B) Ostium secundum ASD C) Membranous VSD D) Cor triatriatum | back 123 A. Common atrium |
front 124 A neonate has a probe-patent foramen ovale found incidentally. Which statement best describes its significance? A) Always causes severe cyanosis B) Usually clinically insignificant C) Requires urgent closure D) Prevents all right-left shunting | back 124 B. Usually clinically insignificant |
front 125 Which congenital heart defect is the most common overall? A) Atrial septal defect B) Persistent truncus arteriosus C) Ventricular septal defect D) Tetralogy of Fallot | back 125 C. Ventricular septal defect |
front 126 A child has the most common type of VSD. Which region is most likely defective? A) Muscular septum B) Membranous septum C) Inlet septum D) Outlet septum | back 126 B. Membranous septum |
front 127 Failure of the interventricular foramen to close most directly reflects failed development of which structure? A) Muscular interventricular septum B) Septum secundum C) Membranous interventricular septum D) Aorticopulmonary septum | back 127 C. Membranous interventricular septum |
front 128 Multiple small defects are scattered throughout the muscular interventricular septum. Which diagnosis fits best? A) Swiss cheese VSD B) Membranous VSD C) Common atrium D) Persistent truncus arteriosus | back 128 A. Swiss cheese VSD |
front 129 Complete absence of the interventricular septum produces which cardiac anatomy? A) Two-chambered heart B) Three-chambered heart C) Four-chambered heart D) Single atrium only | back 129 B. Three-chambered heart |
front 130 Persistent truncus arteriosus results from failure of which structures to develop? A) AV cushions and septum primum B) Truncal ridges and AP septum C) SA valves and sinus horns D) Pulmonary veins and left atrium | back 130 B. Truncal ridges and AP septum |
front 131 Which defect is always present with persistent truncus arteriosus? A) ASD B) PDA C) VSD D) TAPVR | back 131 C. VSD |
front 132 Persistent truncus arteriosus involves arrested development of which structures? A) Outflow tract, semilunar valves, aortic sac B) Inflow tract, AV valves, sinus venosus C) Septum primum, atria, pulmonary veins D) Cardinal veins, SVC, coronary sinus | back 132 A. Outflow tract, semilunar valves, aortic sac |
front 133 An abnormal window connects the aorta and pulmonary trunk. Which defect is this? A) Persistent truncus arteriosus B) Aorticopulmonary septal defect C) Transposition of great arteries D) Tetralogy of Fallot | back 133 B. Aorticopulmonary septal defect |
front 134 Which finding distinguishes aorticopulmonary septal defect from persistent truncus arteriosus? A) Absent semilunar valves B) Mandatory ventricular septal defect C) Pulmonary/aortic valves, intact septum D) Single arterial trunk only | back 134 C. Pulmonary/aortic valves, intact septum |
front 135 In transposition of the great arteries, which ventricular-arterial pairing is correct? A) Aorta-LV, pulmonary trunk-RV B) Aorta-RV, pulmonary trunk-LV C) Aorta-RA, pulmonary trunk-LA D) Aorta-LA, pulmonary trunk-RA | back 135 B. Aorta-RV, pulmonary trunk-LV |
front 136 Transposition of the great arteries results from failure of which process? A) AV cushion fusion B) Septum primum perforation C) Pulmonary vein incorporation D) Aorticopulmonary septum spiraling | back 136 D. Aorticopulmonary septum spiraling |
front 137 In infundibular stenosis, which embryologic structure is underdeveloped? A) Conus arteriosus B) Sinus venosus C) Septum secundum D) Primordial atrium | back 137 A. Conus arteriosus |
front 138 Which combination defines tetralogy of Fallot? A) ASD, PDA, LVH, cyanosis B) PS, RVH, overriding aorta, VSD C) VSD, TAPVR, SVC, stenosis D) AP window, LVH, ASD, PDA | back 138 B. PS, RVH, overriding aorta, VSD |
front 139 Aortic valve stenosis causes hypertrophy of which chamber? A) Right atrium B) Right ventricle C) Left atrium D) Left ventricle | back 139 D. Left ventricle |
front 140 A neonate has a small nonfunctional left ventricle and atretic tricuspid valve. Which defect matches these findings? A) Tetralogy of Fallot B) Hypoplastic left heart syndrome C) Persistent truncus arteriosus D) Aorticopulmonary septal defect | back 140 B. Hypoplastic left heart syndrome |