AP II Fetal Circulation

From which artery does the umbilical artery branch?

Internal iliac artery

What happens to the foramen ovale after birth?

around 1 year it closes to create the fossa ovalis

Blood is carried from the placenta back to the fetus via the umbilical v. which branches near the liver. Some blood is carried into a vessel called the ___________, and from there into the inferior vena cava. The remaining blood flows into the ____________ and is carried to the liver.

ductus venosus . . . . hepatic portal vein

What happens to the ductus venosus after birth?

collapse and persist as fibrous band, called the ligamentum venosum on the inferior surface of liver

What happens to the ductus arteriosus after birth?

collapses and becomes the ligamentum arteriosum around 1-3 months

What happens to the umbilical vein after birth?

collapses and forms a fibrous ligament called the ligamentum teres that attaches the umbilicus to the liver

What happens to the placenta after birth?

is birthed by the mother roughly 15 min after vaginal birth

What happens to the umbilical arteries after birth?

persist as fibrous cords, called medical umbilical ligaments, on the inner abdominal wall

Where does exchange of nutrients and blood gasses occur between the mother and fetus

placenta

Two special shunts exist in the fetal circulation which allow most blood to bypass the pulmonary circulation. Name and describe each of these modifications.

1) Foramen ovale—an opening in the interatrial septum between the L and R atria. 1/3 of the blood passes through this structure. 2) Ductus arteriosus—small vessel connecting the pulmonary trunk to the aorta; 2/3 blood passes through here (therefore, 2/3 of fetal blood takes this path: R. ventricle -> pulmonary trunk -> aorta -> systemic circulation)

How many umbilical arteries are there? How many umbilical veins?

2 umbilical arteries 1 vein

Which of the umbilical vessels carries oxygenated blood and nutrients to the fetus? Which carries deoxygenated blood and metabolic wastes from the fetus to the placenta?

Umbilical arteries carry metabolic waste and CO2 away from the fetus, umbilical veins carry nutrients and O2 to the fetus

The two arteries and vein coil together into a structure called the _________ which attaches at the fetus' _______.

Umbilical cord, naval/umbilicus