Kaplan challenge Q6 - rei

[ArchivalUser]

A 10-year-old boy is brought to his pediatrician because of exercise intolerance. Gradually, over the past six months, he has not been able to do the things he used to. He can no longer run for any significant period of time without getting out of breath and having to stop and sit down. On examination, the pediatrician hears a loud systolic ejection murmur over the midsternal border and the splitting of the second heart sound is wide and fixed. Which of the following is the most likely cause of this defect?

A. Absence of the atrioventricular septum
B. Failure of complete formation of the membranous intraventricular septum
C. Failure of complete formation of the muscular intraventricular septum
D. Failure of complete formation of the septum secundum
E. Persistence of the foramen ovale

Correct answer is D. Why can't it also be E?

[ArchivalUser]

persistent foramen ovale is a "benign" finding and i think its present in about 25% of the population

[ArchivalUser]

so it's a smaller opening that does not cause symptoms? Thanks!

[ArchivalUser]

I was very surprised at this questions. I guess i have to review embriology ... again!

A developmental neuroscientist discovers a marker that is unique to neuroepithelial cells. The marker can be detected using immunofluorescent methods. Which of the following cell types would most likely show positivity for this marker?
A. Astrocytes
B. Enterochromaffin cells
C. Melanocytes
D. Odontoblasts
E. Schwann cells

I'll post the correct answer shortly.

[ArchivalUser]

nice and easy... astrocytes... the rest are neural crest
there's a nice tbl in kaplan that summarizes the derivatives

[ArchivalUser]

good job! I've read that stuff 2-3 times now. Still get it wrong. You're right, answer A