Nervous system

Nervous system

1. Neural plate

   • Comes from ectoderm
   • Formed at week 3
   • The edges approach and form the neural groove
     • They continue to fold until they joint and form the...

2. Neural tube

   • leaves 2 openings, cranial and caudal pores
     • Cranial closes at day 25, whilecaudal two days later
   • forms the brain and spinal cord
     • Brain
       • Primary vesicles
         • Prosencephalon
         • Mesencephalon
         • Rhombencephalon
       • Secondary vesicles
         • Telencephalon
           • Forms cerebral hemispheres
             • lamina terminalis
         • Diencephalon
           • Forms optic outgrowth
           • thalamus
           • hypothalamus
             • Neurohypophysis
               • Adenohypophysis
                 • Rathke's pouch
         • Metencephalon
           • Cerebellum
           • Pons
         • Myelencephalon
           • medulla oblongata
     • Spinal cord
       • Alar plate
         • Sensory nerons
         • posterior
       • Basal plate
         • Motor neurons
         • anterior
       • spinal nerves
       • neuroepithelial cells
         • neuroblasts
           • neurons
           • glial cells
             • Ependymal cells
             • Oligodendroglia
             • astrocytes
             • microglia comes from vascular mesenchyma
     • Week 4
   • Neural crest
     • forms dorsal root ganglia, autonomic ganglia, adrenal medulla, pia-arachnoid sheath, skin melanocytes, connective tissue of cardiac outflow, thyroid parafollicular cells, craniofacial skeleton and teeth odontoblasts.

3. Genes

   • HOX genes
     • anteroposterior axis in the hindbrain and specify rhombomere identity
   • FGF8
     • signal for
       • anterior neural ridge and the rhombencephalic isthmus
   • FOXG1
     • regulates development of the telencephalon
   • SHH
     • ventralizes the forebrain and midbrain
   • BMP 4/7
     • dorsalizing genes