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

C. Splanchnic mesoderm

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

A. Endothelial tube—endocardium

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

C. Endocardium

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

B. Epicardium—mesothelial cells

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

A. Sinus venosus

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

B. Ventral foregut, caudal membrane

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

A. Heart ventral to foregut

After head folding, which positional relationship normally describes the heart relative to the oropharyngeal membrane? A) Dorsal B) Lateral C) Cranial D) Caudal

D. Caudal

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

B. Truncus, conus arteriosus, conus cordis

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

C. Truncus arteriosus

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

B. Truncus arteriosus

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

C. Truncus arteriosus—aortic sac

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

B. Second heart field

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

C. Arterial and venous ends

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

B. Umbilical, vitelline, cardinal veins

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

A. Umbilical vein—chorion

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

C. Vitelline vein—umbilical vesicle

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

D. Common cardinal vein

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

A. Umbilical-chorion, vitelline-vesicle, cardinal-embryo

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

C. Days 23–28

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

B. Dextral looping

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

B. Bulboventricular loop

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

A. Dextral, days 23–28

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

C. Pitx2c

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

A. Left-right heart patterning

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

A. Pitx2c—left-right patterning

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

B. Atrium and sinus venosus

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

A. Atrium dorsal to ventricles

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

B. BMP, Notch, Wnt, SHH

Which signaling molecule is included among cardiac looping regulators? A) SHH B) PTH C) ANP D) ADH

A. SHH

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

A. BMP and Notch

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

B. Transverse pericardial sinus

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

A. Right and left pericardial cavities

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

B. Coordinate contraction, unidirectional flow

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

C. Coordinated unidirectional flow

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

A. Embryo—common cardinal veins

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

C. Umbilical veins

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

C. Vitelline veins

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

A. Cardinal-embryo, umbilical-placenta, vitelline-vesicle

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

A. Primordial atrium, SA valves

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

A. Sinus, atrium, AV canal, ventricle

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

C. Atrioventricular canal

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

B. Sinuatrial valves

Blood pumped from the primordial ventricle travels through which immediate outflow structure? A) Sinus venosus B) Atrioventricular canal C) Bulbus cordis D) Primordial atrium

C. Bulbus cordis

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

A. Bulbus, aortic sac, arch arteries

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

C. Pharyngeal arch arteries

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

A. Sinus venosus to atrium

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

A. Inflow uses sinus venosus

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

C. Weeks 4–8

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

A. Starts week 4, ends week 8

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

B. Cardiac jelly

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

A. Cardiac jelly

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

B. Division of AV canal

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

C. AV endocardial cushions

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

A. Valves and membranous septa

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

B. AV endocardial cushions

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

B. Mesenchymal cells

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

B. TGF-β1, TGF-β2, BMP-2A, BMP-4

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

A. Slug

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

A. Slug and ChALK2

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

A. Septum primum and secundum

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

B. Primum and secundum septa

Foramen primum and foramen secundum develop within which embryonic structure? A) Septum secundum B) Endocardial cushion C) Septum primum D) Sinus venosus

C. Septum primum

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

A. Septum primum

Septum secundum growth occurs during which developmental window? A) Weeks 3–4 B) Weeks 5–6 C) Weeks 7–8 D) Weeks 9–10

B. Weeks 5–6

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

A. Septum secundum

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

B. Right to left

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

A. Right atrium to left atrium

The sinus venosus initially opens into which location? A) Ventral right ventricle B) Dorsal primordial atrium C) Left atrial appendage D) Caudal truncus arteriosus

B. Dorsal primordial atrium

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

A. Primordial atrium

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

B. Vitelline-umbilical transformation

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

A. Anterior cardinal anastomosis

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

A. Vitelline-umbilical transformation, anterior cardinal anastomosis

The superior vena cava is derived from which venous system? A) Vitelline veins B) Umbilical veins C) Cardinal veins D) Pulmonary veins

C. Cardinal veins

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

A. Cardinal veins

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

B. Coronary sinus

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

A. Smooth right atrium

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

A. Left horn—coronary sinus

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

C. Right sinus horn

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

A. Crista terminalis

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

B. IVC and coronary sinus valves

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

A. Cranial part—crista terminalis

The left sinuatrial valve normally fuses with which developing septal structure? A) Septum primum B) Septum secundum C) Bulbar ridge D) Endocardial cushion

B. Septum secundum

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

A. Septum secundum

The primordial pulmonary vein contributes directly to formation of which chamber? A) Right atrium B) Right ventricle C) Left atrium D) Left ventricle

C. Left atrium

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

B. TAPVR

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

A. Pulmonary veins miss left atrium

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

C. Week 7

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

B. Bulbar ridges and endocardial cushion

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

A. Bulbar ridges with cushion

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

B. Right endocardial cushion

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

A. Right endocardial cushion

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

B. Right ventricle and pulmonary trunk

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

A. Interventricular foramen closure

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

C. 18–22 weeks

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

C. 18–22 weeks

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

B. Week 5, bulbar ridges

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

A. Mesenchymal proliferation in bulbus cordis

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

A. Week 5—bulbar ridges

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

C. Weeks 4–8

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

A. Cardiac jelly; AV cushions meet

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

D. Valves and membranous septa

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

B. TGF-β1/2, BMP-2A/4, Slug, ChALK2

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

A. Septum primum and secundum

Foramen primum and foramen secundum form in which structure? A) Septum secundum B) Endocardial cushion C) Bulbar ridge D) Septum primum

D. Septum primum

Septum secundum normally grows during which developmental window? A) Weeks 3–4 B) Weeks 4–5 C) Weeks 5–6 D) Weeks 7–8

C. Weeks 5–6

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

B. Right to left

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

A. Dorsal primordial atrium

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

D. Vitelline-umbilical transformation; cardinal anastomosis

Which embryonic veins give rise to the superior vena cava? A) Umbilical veins B) Cardinal veins C) Vitelline veins D) Pulmonary veins

B. Cardinal veins

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

C. Left horn—coronary sinus

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

A. Right sinus horn

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

D. Cranial—crista terminalis

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

B. IVC and coronary sinus valves

The left SA valve normally fuses with which structure? A) Septum primum B) Endocardial cushion C) Septum secundum D) Bulbar ridge

C. Septum secundum

Which embryonic structure forms the left atrium? A) Primordial pulmonary vein B) Right sinus horn C) Left sinus horn D) Common cardinal vein

A. Primordial pulmonary vein

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

D. TAPVR

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

B. Bulbar ridges and cushion

The membranous interventricular septum derives from which embryonic structure? A) Left sinus horn B) Septum primum C) Right endocardial cushion D) Primordial pulmonary vein

C. Right endocardial cushion

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

A. Right ventricle and pulmonary trunk

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

D. 18–22 weeks

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

B. Bulbar ridges

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

A. Common atrium

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

B. Usually clinically insignificant

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

C. Ventricular septal defect

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

B. Membranous septum

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

C. Membranous interventricular septum

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

A. Swiss cheese VSD

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

B. Three-chambered heart

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

B. Truncal ridges and AP septum

Which defect is always present with persistent truncus arteriosus? A) ASD B) PDA C) VSD D) TAPVR

C. VSD

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

A. Outflow tract, semilunar valves, aortic sac

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

B. Aorticopulmonary septal defect

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

C. Pulmonary/aortic valves, intact septum

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

B. Aorta-RV, pulmonary trunk-LV

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

D. Aorticopulmonary septum spiraling

In infundibular stenosis, which embryologic structure is underdeveloped? A) Conus arteriosus B) Sinus venosus C) Septum secundum D) Primordial atrium

A. Conus arteriosus

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

B. PS, RVH, overriding aorta, VSD

Aortic valve stenosis causes hypertrophy of which chamber? A) Right atrium B) Right ventricle C) Left atrium D) Left ventricle

D. Left ventricle

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

B. Hypoplastic left heart syndrome