1. Fetal Circulation pp

3. Fetal Circulation Fetal heart develops in 3rd-4th week
At end of 8th week, heart is functioning
The fetus does not use pulmonary circuit (can’t breath air inside the womb!)
All nutrients & waste are taken care of via mom

4. Fetal Circulation
Placenta - organ responsible for delivery of nutrients, removal of waste products and delivery of oxygenated blood to the fetus via diffusion and active transport mechanisms. 

5. Fetal Circulation – 4 differences
Umbilical cord
Umbilical vein delivers oxygenated & nutrient rich blood from the placenta to the fetus.
Umbilical artery travels towards the placenta with wastes & connects to iliac arteries
Venous duct
receives blood from the umbilical vein & directs it to the fetus’ inferior vena cava
Function: acts as a liver bypass & this is why chemicals ingested by mom can seriously affect fetus

6. 3. Oval opening (foramen ovale)
an opening between the right atrium and left atrium
Function – to bypass the lungs
If the opening doesn’t close after birth, it can cause mixing of oxygenated & deoxygenated blood
“blue baby”
Corrected with open heart surgery
4. Arterial duct (ductus arteriosus)
connects the pulmonary artery to the aorta
Function – to bypass pulmonary circuit.

8. The path of the blood through the fetus:
Begin with blood collecting in Right Atrium
From there, blood can go into Left Atrium through Oval opening plus into Right Ventricle through atrioventricle valve.
Right Ventricle to Pulmonary Artery. Most of blood will go through arterial duct into aorta.
D. Aorta to tissue.

9. Umbilical arteries lead to placenta, where exchange of gases and nutrients take place.
Umbilical vein carries O2 rich blood.
It enters the venous duct, passes through liver.
H. Venous duct joins with inferior vena cava (it mixes here with deoxygenated blood) and this mixed blood goes back to the heart.