The development of the nervous system begins in the third week of gestation with gastrulation, forming the germ layers: ectoderm, mesoderm, and endoderm. The notochord induces the formation of the neural plate, which folds and fuses to form the neural tube, the precursor of the central nervous system. This process, called neurulation, culminates in the third week with the closure of the anterior and posterior neuropores. Failure to close properly causes neural tube defects. Neural crest cells migrate and differentiate into various cell types, including sensory neurons, ganglia, Schwann cells, melanocytes, and other structures of the peripheral and vegetative nervous system. The neural tube segments into primary and secondary vesicles, forming brain structures and ventricles. Segmentation is crucial for determining the formation of motor and sensory nuclei of the cranial nerves. The rhombomeres of the hindbrain generate neuronal cells specific to various cranial nerves. The spinal cord is differentiated into ventricular areas, mantle and marginal areas, with motor basal plates and sensory wing plates. From the fourth week, motor and sensory nerve fibers develop, forming the spinal nerves. The vegetative nervous system, derived from the neural crest, forms sympathetic chains and parasympathetic ganglia, essential for autonomic function.