Fetal conditions - Fetal circulation

Question 1

Shunt closure

• Ductus venosus
• Ductus arteriosus
• Foramen ovale

Answer 1

• Ductus venosus
  
  • Functional – 10-96 hours
  • Anatomic – 2-3 weeks
• Ductus arteriosus
  
  • Functional – 10-12 hours
  • Anatomic – 2-3 weeks
• Foramen ovale
  
  • Functional – Several minutes
  • Anatomic – 3 months
• Memory aid:*
• Magic number is 3 for anatomic closure

Question 2

Shunt remnant

• Ductus venosus
• Ductus arteriosus
• Foramen ovale

Answer 2

• Ductus venosus
  
  • Ligamentum venosum
  • Falciform ligament
• Ductus arteriosus
  
  • Ligamentum arteriosum
• Foramen ovale
  
  • Fossa ovalis
• Summary:*
• The ductus becomes ligamentum

Question 3

Blood vessel closure

• When
• Remnant
  
  • Umbilical artery
  • Umbilical vein

Answer 3

• When
  
  • Umbilical artery
    
    • 3-4 days
  • Umbilical vein
    
    • 3-4 days
• Remnant
  
  • Umbilical artery
    
    • Umbilical ligament
  • Umbilical vein
    
    • Ligamentum teres
• Memory aid:*
• AVA become UL-L_T-UL

Question 4

Pathway of oxygenated blood

Answer 4

Umbilical vein → ductus venosus → IVC → RA → foramen ovale → LA → LV → Aorta

Question 5

Pathway of unoxygenated blood

Answer 5

SVC → RA → RV → pulmonary trunk → ductus arteriosus → aorta

Question 6

The ____ may persist as the ____ arteries which supply the urinary bladder

Answer 6

• Proximal portion of the umbilical artery
• Superior vesical