Which set of plates run the length of the spinal cord?

Which set of plates run the length of the spinal cord?

• A. The ventral (basal) plates, the dorsal (alar) plates, the root plate, and the floor plate
• B. The ventral (basal) plates and dorsal (alar) plates only
• C. The root plate and the floor plate only
• D. The ventral (basal) plates, the root plate only

Answer: (A)

In spinal cord development, several longitudinal plates extend from one end to the other, shaping the entire cord. The ventral (basal) plate runs along the full length and becomes the ventral horn with motor neurons. The dorsal (alar) plate also runs the length and forms the dorsal horn with sensory interneurons. The floor plate sits at the ventral midline and extends the entire length, guiding axon growth and contributing to patterning. The root plate is a longitudinal region associated with where the nerve roots emerge, also running the full length of the spinal cord. Because each of these plates extends along the entire spinal cord, this set—ventral basal plate, dorsal alar plate, the floor plate, and the root plate—is the complete answer.

In spinal cord development, several longitudinal plates extend from one end to the other, shaping the entire cord. The ventral (basal) plate runs along the full length and becomes the ventral horn with motor neurons. The dorsal (alar) plate also runs the length and forms the dorsal horn with sensory interneurons. The floor plate sits at the ventral midline and extends the entire length, guiding axon growth and contributing to patterning. The root plate is a longitudinal region associated with where the nerve roots emerge, also running the full length of the spinal cord. Because each of these plates extends along the entire spinal cord, this set—ventral basal plate, dorsal alar plate, the floor plate, and the root plate—is the complete answer.