Foetal circulation

Question 1

circulation in an adult

Answer 1

Nutrition storage/detoxification - Liver

Gas Exchange - Lungs

Question 2

circulation in foetus

Answer 2

Nutrition storage/detoxification - Placenta
Gas Exchange - Placenta
Foetus develops 3 major shunts and openings to restrict blood flow to the liver and the lungs.

Question 3

Foetus develops 3 major shunts and openings to restrict blood flow to the liver and the lungs:

Answer 3

Ductus Venosus
Ductus Arteriosus
Oval foramen

Protection

Nourishment

Question 4

Ductus Venosus

Answer 4

Shunts 50% blood from umbilical vein to the caudal vena cava bypassing the liver

Regulated by sphincter

Question 5

Ductus Arteriosus

Answer 5

90% Blood in pulmonary artery shunted to aorta to bypass the developing lungs
Protects lungs from overload
Exercises and develops the right ventricle

Question 6

Oval Foramen

Answer 6

Shunts blood from right atrium to left atrium, away from developing lung

Question 7

Foetal circulation

Answer 7

1 x umbilical vein
2 x umbilical arteries
Ductus venosus shunt
Oval foramen shunt
Ductus arteriosus shunt

Question 8

Peri partum changes in foetal circulation

Answer 8

Pressure changes within the lungs as the newborn breathes and placenta is abrupted
Oval foramen closes
Ductus arteriosus closes
Ductus venosus closes
These closures are functional within hours and anatomical/permanent within days
Controlled by pressure changes and chemical mediators, e.g. prostaglandins