<P> In the developing chordate ( including vertebrates ) , the neural tube is the embryo 's precursor to the central nervous system , which comprises the brain and spinal cord . The neural groove gradually deepens as the neural folds become elevated , and ultimately the folds meet and coalesce in the middle line and convert the groove into the closed neural tube . In humans , neural tube closure usually occurs by the fourth week of pregnancy ( 28th day after conception ) . The ectodermal wall of the tube forms the rudiment of the nervous system . The centre of the tube is the neural canal . </P>
<P> In the developing chordate ( including vertebrates ) , the neural tube is the embryo 's precursor to the central nervous system , which comprises the brain and spinal cord . The neural groove gradually deepens as the neural folds become elevated , and ultimately the folds meet and coalesce in the middle line and convert the groove into the closed neural tube . In humans , neural tube closure usually occurs by the fourth week of pregnancy ( 28th day after conception ) . The ectodermal wall of the tube forms the rudiment of the nervous system . The centre of the tube is the neural canal . </P>
as part of embryonic development the neural tube will become the
as part of embryonic development the neural tube will become the
central nervous system
central nervous system