In neurulation, what does the neural tube become in the development of the nervous system?

During neurulation, the neural tube forms from the neural plate as a precursor to the central nervous system (CNS). This process is a critical stage in embryonic development and sets the foundation for the brain and spinal cord. The neural tube undergoes complex morphogenetic movements that ultimately delineate the CNS from other tissues in the developing embryo.

As the neural tube develops, it differentiates into various structures, including the forebrain, midbrain, hindbrain, and spinal cord. The proper closure and formation of the neural tube are essential for normal development; defects in this process can lead to serious conditions such as spina bifida or anencephaly.

In contrast, the peripheral nervous system (PNS) arises from neural crest cells, which are not part of the neural tube itself. This distinction is key to understanding the roles of different embryonic tissues in forming the nervous system. Options related to all body tissues or the placenta do not directly pertain to the formation of the nervous system and can be ruled out based on their lack of relevance to the specific developmental pathway of the neural tube. Thus, the neural tube’s direct transformation into the CNS supports the accuracy of the correct answer.