17- Neurulation drawing

Neurulation is the process of folding of the neural plate and closure of the neural tube. This classic drawing illustrates the sequence of neural tube folding in three shades of blue, starting from the upper left image and moving clockwise.

• The notochord induces the ectoderm in the dorsal midline to thicken and form the neural plate.
• The edges of the neural plate, the neural folds, bend toward each other.
• The neural folds meet dorsally and form the neural tube and the overlying epidermis. 

Ectoderm illustrated in light blue becomes the neural tube and develops into the central nervous system (brain, brainstem, and spinal cord). Ectoderm colored dark blue gives rise to neural crest cells that migrate throughout the body and develop into the peripheral nervous system. Ectoderm that forms epidermis is shown in medium blue and forms the skin covering the spine.