DEVELOPMENT OF THE BRAIN, SPINAL CORD AND NERVES Reading:
Langmans Medical Embryology Chapter 20 1. Development of the
Spinal Cord and Nerves Entering the third week the ectoderm
overlying the notochord thickens and forms the neural plate. The
neural plate changes shape in the following days as it begins to
fold and the lateral edges begin to come to the midline. At this
time the neural plate is described as consisting of two neural
folds. The neural folds meet in the midline and at this point a
neural tube is formed. The neural tube first occurs in the
cervical region and the fusion of the neural folds proceeds both
cephalically and caudally. In addition to the formation of the
neural tube, a group of cells at the junction of the neural
plate and the remaining ectoderm also differentiate and become
located lateral and dorsal to the neural tube. This cluster of
cells is call the neural crest. The wall of the neural tube is
made up of neural ectodermal cells that are called the
neuroepithelium. These neuroepit