Foetal circulation Flashcards
circulation in an adult
Nutrition storage/detoxification - Liver
Gas Exchange - Lungs
circulation in foetus
Nutrition storage/detoxification - Placenta
Gas Exchange - Placenta
Foetus develops 3 major shunts and openings to restrict blood flow to the liver and the lungs.
Foetus develops 3 major shunts and openings to restrict blood flow to the liver and the lungs:
Ductus Venosus
Ductus Arteriosus
Oval foramen
Protection
Nourishment
Ductus Venosus
Shunts 50% blood from umbilical vein to the caudal vena cava bypassing the liver
Regulated by sphincter
Ductus Arteriosus
90% Blood in pulmonary artery shunted to aorta to bypass the developing lungs
Protects lungs from overload
Exercises and develops the right ventricle
Oval Foramen
Shunts blood from right atrium to left atrium, away from developing lung
Foetal circulation
1 x umbilical vein 2 x umbilical arteries Ductus venosus shunt Oval foramen shunt Ductus arteriosus shunt
Peri partum changes in foetal circulation
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