The neural folds of the embryonic disk fold medially, eventually fusing to form the neural tube. Fusion progresses in which of the following directions?
A) Caudally to cranially
B) It all fuses at once
C) Cranially to caudally
D) Medially to craniocaudally

Question

Quizplus · Accepted Answer

The neural tube, which eventually forms the central nervous system, starts to fuse in the middle and then zips up both cranially (towards the head) and caudally (towards the tail) from that central point. This means the fusion progresses in both directions from the center, but the question specifically asks for the direction, implying a singular direction of progression, which is more accurately described as cranially to caudally for the overall process.

The Neural Folds of the Embryonic Disk Fold Medially, Eventually