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1. Which statement is TRUE about the prenatal heart?

a. In the developing fetus, blood is shunted from the left atrium to the right atrium.
b. The fetus has greater pulmonary arterial pressure than the newborn.
c. The interatrial septum forms a solid, fused wall between left and right atrium by 8 weeks of development.
d. The prenatal left atrium is the first heart chamber to receive oxygenated blood.
e. Don't know

2. The septum primum first forms by:

a. The end of the 2nd week of development
b. The end of the 3rd week of development
c. The end of the 4th week of development
d. The end of the 5th week of development
e. Don't know

3. Which statement is TRUE about interatrial septum development?

a. The foramen (ostium) secundum is an opening in the septum secundum.
b. The septum primum is thick and muscular, compared to the thin and membranous septum secundum.
c. The foramen secundum is also known as the foramen ovale.
d. The foramen (ostium) primum disappears when the septum primum and endocardial cushions fuse.
e. Don't know

4. Where is the foramen ovale located?

a. On the posterior-inferior surface of the septum secundum.
b. On the superior surface of the septum primum.
c. On the inferior surface of the septum primum.
d. On the superior aspect of the endocardial cushions.
e. Don't know

5. What is the valve of the foramen ovale?

a. A portion of the septum secundum
b. The superior portion of the fused endocardial cushions
c. The septum primum
d. A thick flap of tissue located in the right atrium that covers the foramen ovale
e. Don't know

6. Which two structures fuse to form a solid interatrial septum?

a. Septum primum and the valve of the foramen ovale
b. Septum primum and the endocardial cushions
c. Septum secundum and the valve of the foramen ovale
d. Septum secundum and the endocardial cushions
e. Don't know

7. When a baby is born and takes its first breath, what changes occur to prevent further blood shunting between the atria?

a. The components of the interatrial septum fuse immediately after birth
b. Blood in the left atrium pushes the valve of the foramen ovale against the septum secundum, functionally closing off the foramen ovale.
c. Pressure continues to be greater on the right side of the heart versus the left side, preventing further blood shunting.
d. All of the above.
e. Don't know

Last updated 11 September 2002

For more information, contact:
Valerie Dean O'Loughlin, Ph.D.
Assistant Professor of Anatomy and
Director of Undergraduate Human Anatomy
Jordan Hall 010A
Medical Sciences
Indiana University
Bloomington, IN 47405
(812) 855-7723 (voice)
(812) 855-4436 (fax)
vdean@indiana.edu