Chapter 13, Problem 1CYU

Summary Introduction

To review:

The parts of an adult brain that develop from the telencephalon and mesencephalon.

Introduction:

Brain is one of the major organs of an animal body made up of a large mass of nerve tissues, secured inside the skull. It is involved in various essential functions, such as controlling the blood pressure, heart and respiratory rate. It helps in the maintenance of the internal body environment by regulating the endocrine and nervous system.

Explanation of Solution

During the 4th week of development, the brain seems like a rostral part of the neural tube. The expansion and constriction of the brain begins in the 4th week of development. This results in the appearance of its three basic vesicles, namely rhombencephalon, prosencephalon, and mesencephalon. The caudal part of the neural tube develops as the spinal cord.

During the fifth week, five secondary vesicles develop from these three primary vesicles. The five secondary vesicles are telencephalon and diencephalon (from prosencephalon) myelencephalon, and metencephalon (from rhombencephalon). The mesencephalon remains undivided. The telencephalon gives rise to the cerebral hemispheres or cerebrum. The midbrain is formed by the mesencephalon.