Embryology

Question 1

Truncus Arteriosus gives rise to…

Answer 1

Ascending aorta and pulmonary trunk

Question 2

Bulbus Cordis gives rise to…

Answer 2

Smooth parts (outflow tract) of L and R ventricles

Question 3

Primitive ventricle gives rise to…

Answer 3

Trabeculated L and R ventricles

Question 4

Primitive atria gives rise to…

Answer 4

Trabeculated L and R atria

Question 5

L horn of Sinus Venosus gives rise to…

Answer 5

Coronoary Sinus

Question 6

R horn of Sinus Venosus gives rise to…

Answer 6

Smooth part of R atrium

Question 7

R common cardinal vein and R anterior cardinal vein give rise to…

Answer 7

SVC

Question 8

What is the pathway to the formation of the asc. aorta and pulm. trunk

Answer 8

Neural crest migration–>Truncal and bulbar ridges that spiral and fuse to form the AP septum–>Asc. Aorta and Pulm. Trunk

Question 9

What is the different pathology that can come from malformation of the Truncus Arteriosis

Answer 9

TGV (failure to spiral)
TOF (skewed AP septum devo)
Persistent TA (partial AP septum development)

Question 10

What is the first step in IV septum development

Answer 10

Muscular ventricular septum forms and the opening is called the IV foramen

Question 11

What is the second step in IV septum development

Answer 11

AP septum rotates and fuses with muscular ventricular septum to form membranous IV septum, closing the IV foramen

Question 12

What is the third step in IV septum development

Answer 12

Endocardial cushion growth separating the atria and ventricles and contributes to separation of atria and also to the membranous portion of the IV septum

Question 13

What is the pathology that can result from malformation of IV septum

Answer 13

TGA or Persistent TA (improper neural creast migration)

L to R shunt (membranous septal defect)–>Can reverse to R to L due to onset of pulmonary HTN (Eisenmenger’s syndrome)

Question 14

Step 1 in IA septum devo

Answer 14

-Septum primum grows toward endocardial cusions

Question 15

Step 2 in IA septum devo

Answer 15

• Froamen Primum disappears

- Perforations in septum primum forms foramen secundum

Question 16

Step 3 in IA septum devo

Answer 16

• Froamen secundum maintains R to L flow

- Septum secundum begins to grow

Question 17

Step 4 in IA septum devo

Answer 17

-Septum secundum contains foramen ovale

Question 18

Step 5 IA septum devo

Answer 18

• Upper part of septum primum degenerates

- Septum secundum enlarges

Question 19

Step 6 IA septum devo

Answer 19

-Remaining part of septum primum forms the valve of foramen ovale

Question 20

What fuses to form the atrial septum

Answer 20

-Septum secundum and septum primum

Question 21

What pathology results from malformation of IA septum

Answer 21

Patent foramen ovale (failure of septum primum and septum secundum to fuse after birth)

Question 22

Where does fetal erythropoiesis occur?

Answer 22

Young Liver Synthesizes Blood

• Yolk sac (3-10 weeks)
• Liver (6 weeks-birth)
• Spleen (15-30 weeks)
• Bone marrow (22 weeks-adult)

Question 23

What is the postnatal derivative of the umbilical vein?

Answer 23

Ligamentum teres hepatis

Note: Contained in falciform ligament

Question 24

What is the postnatal derivative of the Umbilical arteries?

Answer 24

Medial umbilical ligaments

Question 25

What is the postnatal derivative of the Ductus Arteriosus?

Answer 25

Ligamentum Arteriosum

Question 26

What is the postnatal derivative of Ductus Venosus?

Answer 26

Ligamentum venosum

Question 27

What is the postnatal derivative of Foramen ovale?

Answer 27

Fossa ovalis

Question 28

What is the fetal postnatal derivative of Allantois?

Answer 28

Urachas-median umbilical ligament
Note: Urachas part of allantoic duct that runs between the bladder and the umbilicus (Urachal cyst or sinus is a remnant)

Question 29

What is the fetal postnatal derivative of the notochord?

Answer 29

Nucleus pulposus of IV disk