Which factors contribute to maintaining a patent ductus ...

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Which factors contribute to maintaining a patent ductus arteriosus during fetal life? 1. Large amounts of fetal hemoglobin 2. Low PaO2 3. Presence of LDH 4. Presence of prostaglandins
 
  a. 1, 2, and 3
  b. 2 and 4
  c. 3 only
  d. 1, 2, 3, and 4

Question 2

In the fetal heart, the foramen ovale allows blood to flow between which two structures?
 
  a. Bypass the liver and enter the inferior ve-na cava.
  b. Pulmonary artery to aortic arch.
  c. Right atrium to left atrium.
  d. Right atrium to left ventricle.

[samiel-sayed]

Answer to Question 1

ANS: B
The relatively low PO2 and various prostaglandins in fetal blood cause the ductus arteriosus, a muscular vessel attached to the trunk of the pulmonary artery and the aorta, to dilate and the pulmonary arteries to constrict.

Answer to Question 2

ANS: C
Approximately 50 of this blood is shunted from the right atrium into the left atrium through an opening in the interatrial septum called the foramen ovale.

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TYSM

[lcapri7]

Excellent