Question

The brain and spinal cord develop from ectoderm arranged in a tubular structure called the neural tube. The anterior part of the neural tube expands, and constrictions appear that create multiple regions. Arrange the parts of the embryonic brain chambers in a 5 week embryo from top to bottom.
A. Diencephalon
B. Myelencephalon
C. Metencephalon
D. Mesencephalon
E. Telencephalon
Choose the most appropriate answer from the options given below:

• A. A, B, C, D, E
• B. A, E, C, D, B
• C. E, A, D, C, B
• D. C, B, D, A, E

Hint:

Remember the alphabetical and hierarchical order. The forebrain divides into T and D. The midbrain (Mesencephalon) stays the same. The hindbrain divides into Met- and Mye-. Alphabetically, Met- comes before Mye-. This gives the sequence T, D, Mes, Met, Mye.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The development of the central nervous system begins with the formation of the neural tube. The anterior (rostral) end of this tube undergoes differentiation to form the brain. Initially, three primary brain vesicles form: the prosencephalon (forebrain), mesencephalon (midbrain), and rhombencephalon (hindbrain). By the fifth week of development, these three vesicles further differentiate into five secondary vesicles. The question asks for the correct order of these five vesicles from anterior to posterior (top to bottom).

Step 2: Detailed Explanation of the Sequence:
The development from three to five vesicles is as follows:
- The Prosencephalon (forebrain) divides into: 1. E. Telencephalon (most anterior), which will become the cerebral hemispheres. 2. A. Diencephalon, which will become the thalamus, hypothalamus, etc. - The Mesencephalon (midbrain) remains as: 3. D. Mesencephalon. - The Rhombencephalon (hindbrain) divides into: 4. C. Metencephalon, which will become the pons and cerebellum. 5. B. Myelencephalon (most posterior), which will become the medulla oblongata.

Step 3: Final Answer:
Arranging these five secondary vesicles in order from top (anterior) to bottom (posterior), we get: Telencephalon \(\rightarrow\) Diencephalon \(\rightarrow\) Mesencephalon \(\rightarrow\) Metencephalon \(\rightarrow\) Myelencephalon.
This corresponds to the letter sequence E, A, D, C, B. Therefore, option (C) is correct.