Embryology

Question 1

Cardinac looping is primarily due to ______?

Answer 1

Differential growth of bulbous cordis and primative left ventricle

Question 2

What is the embryological source of the ductus arteriosus?

Answer 2

Sixth aortic arch

Question 3

A 24-year-old woman underwent a physical examination that revealed an apex beat located on 5th right intercostal space. What is the primary cause of this anomaly?

Answer 3

Dextrocardia

Question 4

Sinoatrial (SA) node is formed from what structure?

Answer 4

VLPM

Question 5

Neural tube formation is induced by what structure?

Answer 5

Notocord

Question 6

A patent foramen ovalis is due to a defect in which area?

Answer 6

Septum primum

Question 7

Incomplete fusion of the endocardial cushions with the septum intermedium is usually associated with which of the type of atrial septal defect (ASD)?

Answer 7

Primum type atrial septal defect

Question 8

Closure of foramen secundum results from fusion of the:

Answer 8

Septum secundum and atrial walls

Question 9

The truncus arteriosus of the primitive heart is partitioned by:

Answer 9

The conotruncal/ aorticopulmonary septum

Question 10

What do the subcardinal veins form?

Answer 10

Part of the inferior vena cava, renal veins and gonadal veins

Question 11

What do the supracardinal veins form?

Answer 11

Part of the inferior vena cava, the intercostal veins, hemiazygos vein and azygos vein

Question 12

What does the membranous ventricular septum form from?

Answer 12

Neural crest cells

Question 13

From what structure does the portal vein form?

Answer 13

Viteline vein

Question 14

What are the four defects of Tetralogy of Fallot

Answer 14

1) Ventricular septal defect (VSD)
2) Pulmonary valve stenosis
3) Misplaced aorta
4) Thickened right ventricular wall (right ventricular hypertrophy)

Question 15

A patent foramen ovalis is due to a defect in which area?

Answer 15

Septum primum

Question 16

The narrowing of the pyloric lumen in congenital pyloric stenosis results primarily from:

Answer 16

Hypertropy of the circular muscular layer

Question 17

The junction of the endodermal epithelium of the hindgut and the ectodermal epithelium of the proctodeum is believed to be indicated by the:

Answer 17

Pectinate line

Question 18

Annular pancreas is due to which of the following malformed processes

Answer 18

Ventral pancreatic bud rotating ventrally to fuse with dorsal pancreatic bud

Question 19

The cloaca is divided into the following structures:

Answer 19

Hindgut and proctoderm

Question 20

The midgut is located only on 1 side. This anomaly would be caused by disruption of which normal embryological processes?

Answer 20

Midgut undergoes 270 degrees of rotation

Question 21

A infant is brought into the clinic with complaints of chronic discharge from the umbilicus. The embryological basis of this pathology is:

Answer 21

Urachal fistula

Question 22

Pulmonary surfactant is produced by:

Answer 22

Type II alveolar epithelial cells

Question 23

What are the stages of lung development and when do they occur?

Answer 23

Weeks 4-5 = Embryonic 
Weeks 5-17 = Pseudoglandular
Weeks 16-25 = Canalicular
Weeks 24-40 = Saccular
Fetal-8 y.o. = Alveolar

Question 24

Hyaline membrane disease causes respiratory distress and may cause death in newborn infants. It is commonly associated with:

Answer 24

Surfactant deficiency

Question 25

Tracheofistula is commonly associated with:

Answer 25

Esophageal atresia

Question 26

Trachea and bronchi are derived from what embryological source?

Answer 26

Visceral lateral plate mesoderm

Question 27

What does the superior vena cava form from?

Answer 27

Right cardinal vein and right vitelline vein