chapter 2 fetal gas exchange and circulation Flashcards
when is the heart developed
during the 3rd week
what happens during the 4th week of gestation to the heart
bulbis corids, ventricular bulge, atrial bulge
what are the 3 fetal shunts
foramen ovale, ductus venous, ductus arteriousus
what is the purpose of the fetal circulation pathway
it allows for shunting of blood flow around the fetal liver and lungs
how much blood does the ductus venous shunt
30-50% of the oxygen rich blood around the fetal liver and flows into the right atrium
where does the blood flow through the foramen ovale shunt
blood flows from the RA into the LA
where does blood flow from pulmonary veins
it goes into LA then into the LV, out the aortic valve - supplying blood with the highest oxygen content to the head, right arm, and coronary circulation
how does blood flow through the ductus arteriousus
the high PVR causes most of the pulmonary artery blood flow from the RV to bypass the lungs, flowing through the ductus arteriosus
what happens on day 21 in the heart
it is formed
what happens on day 22 in the heart
the heart beats
what changes are seen with pressure during the transition to uterine life
decreased PVR
decreased pressure in right heart
increased pressure in left heart
