Chapter 13, Problem 1RAC

Which of these parts of the embryonic brain is correctly matched with the structure it becomes in the adult brain?

1. Mesencephalon —midbrain
2. metencephalon—medulla oblongata
3. myelencephalon—cerebrum
4. telencephalon— pons and cerebellum

Summary Introduction

Introduction:

The brain is divided into three parts, each of which performs a complex set of functions. The three parts of the brain are forebrain, midbrain, and hindbrain. The brain has three visual portions that are cerebrum, cerebellum and medulla oblongata.

Answer to Problem 1RAC

The correct answer is option (a) mesencephalon-midbrain.

Explanation of Solution

Explanation/justification for the correct answer:

Option (a) mesencephalon-midbrain. The midbrain is formed by the mesencephalon. The midbrain connects the forebrain to the hindbrain. The mesencephalon forms the future or adult midbrain along with adult tectum, pretectum, cerebral aqueduct, and cerebral peduncle. So, the correct answer is option (a).

Explanation for incorrect answer:

Option (b) metencephalon-medulla oblongata. The metencephalon is the part of the embryonic brain that forms the hindbrain. This hindbrain then differentiates into pons and cerebellum. So, this is an incorrect option.

Option (c) myelencephalon-cerebrum. The myelencephalon forms the posterior part of the hindbrain in adults. The posterior portion forms medulla oblongata. So, this is an incorrect answer.

Option (d) telencephalon-pons and cerebellum. Telencephalon forms the cerebrum that forms that major part of the brain and subcortical structures and pathways. So, this is an incorrect answer.

Conclusion

The mesencephalon forms the adult midbrain that functions to connect the midbrain with the hindbrain and forms other structures like tectum, and pretectum. Hence, the correct answer is option (a) mesencephalon-midbrain.