foetal circulation

Question 1

what organ is essential for gas exchange and provision of nutrients/detoxification in foetus’?

Answer 1

placenta

Question 2

what are the 3 shunts of the foetus?

Answer 2

ductus venosus
ductus arteriosus
oval foramen

Question 3

where is the oval foramen?

Answer 3

hole between the RA to the LA (shunts blood in this direction)

Question 4

what is the physiology of the ductus venosus?

Answer 4

• shunts blood from the UMBILICAL VEIN to the CAUDAL VENA CAVA by bypassing the LIVER
• regulated by a sphincter

Question 5

what does the ductus arteriosus do?

Answer 5

shunts blood to the aorta from pulmonary arteries

Question 6

what are the branches off of the aorta?

Answer 6

coronary arteries
brachycephalic trunk
subclavian arteries

Question 7

what does the descending aorta split into?

Answer 7

iliac arteries

Question 8

what part of the body do the iliac arteries supply?

Answer 8

the hind limbs

Question 9

what do the umbilical arteries do?

Answer 9

transport oxygen and nutrient depleted blood back to the placenta

Question 10

what are the main structures of foetal circulation?

Answer 10

umbilical vein
ductus venosus
oval foramen
ductus arteriosus
umbilical arteries x2

Question 11

briefly describe foetal circulation

Answer 11

• oxygen and nutrient-rich blood is brought in from the placenta through the umbilical vein
• the blood goes through 3 shunts; ductus venosus bypassing the liver; oval foramen (flap controlled by pressure) RA to the LA; ductus arteriosus to the aorta from pulmonary trunk
• oxygen and nutrient depleted blood then carries down the descending aorta through the umbilical arteries back to the placenta
  OR
• blood is carried through the iliac arteries to supply the hind limbs

Question 12

what happens to the shunts postpartum?

Answer 12

chemical mediators, prostaglandins, control the permanent closure of the shunts through pressure