| Term 
 | Definition 
 
        | as a flat sheet of mesenchymal cells |  | 
        |  | 
        
        | Term 
 
        | what does the embryonic sheet of mesenchymal cells doe |  | Definition 
 
        | forms a hole in the middle of the sheet and the cells invaginate into the hol |  | 
        |  | 
        
        | Term 
 | Definition 
 
        | the invagination of mesenchymal cells into the hole |  | 
        |  | 
        
        | Term 
 
        | what 3 primary germ layers are formed by gastrulation |  | Definition 
 
        | ectoderm, mesoderm, endoderm |  | 
        |  | 
        
        | Term 
 
        | what is the key consequence of gastrulation |  | Definition 
 | 
        |  | 
        
        | Term 
 | Definition 
 
        | cylinder of mesodermal cells that extends from anterior-posterior in the midline of the embryo |  | 
        |  | 
        
        | Term 
 
        | what is the neuroectoderm |  | Definition 
 
        | the ectoderm directly above the notochord |  | 
        |  | 
        
        | Term 
 
        | what will the neuroectoderm become |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what does the notochord do |  | Definition 
 
        | sends inductive/instructive molecular signals to neuroectoderm cells, instructing them to become neural precursor cellss |  | 
        |  | 
        
        | Term 
 
        | when does neurulation occur |  | Definition 
 | 
        |  | 
        
        | Term 
 | Definition 
 
        | formation of the primitive nervous system |  | 
        |  | 
        
        | Term 
 
        | what do the signalled neuroectoderm cells do in neurulation |  | Definition 
 
        | thicken into the neural plate |  | 
        |  | 
        
        | Term 
 | Definition 
 
        | columnar epithelium formed by neuroectoderm cells |  | 
        |  | 
        
        | Term 
 
        | how is the neural tube formed |  | Definition 
 
        | lateral margins of the neural plate fold inward and upward |  | 
        |  | 
        
        | Term 
 
        | what does the neural tube become |  | Definition 
 
        | brain and spinal cord = entire CNS |  | 
        |  | 
        
        | Term 
 | Definition 
 
        | mesoderm adjacent to the neural tube |  | 
        |  | 
        
        | Term 
 | Definition 
 
        | axial muscles and skeleton/vertebrae |  | 
        |  | 
        
        | Term 
 
        | where does the neural tube usually close |  | Definition 
 
        | first at center then at both ends |  | 
        |  | 
        
        | Term 
 
        | what do we call cells in the neural tube |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what do neural precursor cells become |  | Definition 
 
        | first neuroblasts, then neurons |  | 
        |  | 
        
        | Term 
 
        | what do neuroblasts become |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what is formed by ventral midline cells in the neural tube |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what do cells in the floor plate do |  | Definition 
 
        | tell other cells in the neural tube whether to become motor or sensory neurons |  | 
        |  | 
        
        | Term 
 
        | what determines whether cells in the neural tube will become motor or sensory neurons |  | Definition 
 
        | cells that are close to the floor plate are told to become motor neurons. Cells that are farther away don’t' get the memo and will become sensory neurons |  | 
        |  | 
        
        | Term 
 | Definition 
 | 
        |  | 
        
        | Term 
 | Definition 
 | 
        |  | 
        
        | Term 
 
        | where are motor neurons formed |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | are motor neurons formed ventrally or dorsally |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | do motor neurons come out of the spinal cord at the ventral or dorsal horn |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what are the most dorsal cells of the neural tube |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what is the sulcus limitans |  | Definition 
 
        | limit of wher eneurons will be motor or sensory neurons |  | 
        |  | 
        
        | Term 
 
        | in the brainstem, are motor nuclei medial or lateral |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | in the brainstem, are sensory nuclei medial or lateral |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what do neural crest cells do after they are formed |  | Definition 
 
        | migrate away from the neural tube along specific pathways, which influences their final destination/fate |  | 
        |  | 
        
        | Term 
 
        | what 5 things can neural crest cells eventually become, based on their final destination |  | Definition 
 
        | 1. sensory neurons in the dorsal root ganglia; 2. postganglionic autonomic nerves; 3. chromaffin cells of the adrenal gland; 4. non-neural cells (melanocytes, cartilage, bone cells); 5. schwann cells in the PNS |  | 
        |  | 
        
        | Term 
 
        | if I'm a neuron in the basal plate, what am i |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | if I'm a neuron in the alar plate, what am i |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what is the result of failure of the posterior neural tube to close completely |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what is the result of failure of the anterior neural tube to close completely |  | Definition 
 | 
        |  | 
        
        | Term 
 | Definition 
 | 
        |  | 
        
        | Term 
 
        | what are 2 potential causes for neural tube abnormalities |  | Definition 
 
        | retionic acid excess, folic acid insufficiency |  | 
        |  | 
        
        | Term 
 
        | what can retinoic acid excess do |  | Definition 
 
        | inhibit neural tube closure |  | 
        |  | 
        
        | Term 
 
        | what can folic acid insufficiency do |  | Definition 
 
        | alter proper neural tube formation by disputing cell division and motility |  | 
        |  | 
        
        | Term 
 
        | what does retinoic acid come from |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what is spina bifida occulta |  | Definition 
 
        | defect in vertebrae that doesn't affect neural tissue |  | 
        |  | 
        
        | Term 
 
        | what is spina bifida cystica |  | Definition 
 
        | neural tissue and/or meninges protrude through the defect in the vertebrae |  | 
        |  | 
        
        | Term 
 | Definition 
 
        | meninges protrude through defect in vertebrae. Can be fixed surgically |  | 
        |  | 
        
        | Term 
 | Definition 
 
        | nerves entering spinal cord don't form properly. Lower limb paralysis and bladder/bowel problems |  | 
        |  | 
        
        | Term 
 
        | what forms at the anterior bend of the neural tube |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what does the balloon at the very anterior end of the neural tube form |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what is another term for forebrain |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what forms in the cephlic flexure |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what is another term for midbrain |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what forms behind the cephalic flexure |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what is another term for hindbrain |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what bend is located behind the hindbrain |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what forms the ventricals |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what does the prosencephalon divide into |  | Definition 
 
        | telencephalon and diencephalon |  | 
        |  | 
        
        | Term 
 
        | what does the rhombencephalon divide into |  | Definition 
 
        | metencephalon and mylencephalon |  | 
        |  | 
        
        | Term 
 
        | what does the metencephalon become |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what does the mylencephalon become |  | Definition 
 | 
        |  | 
        
        | Term 
 
        | what is significant about the growth of the telencephalon |  | Definition 
 
        | grows and curls around in a C-shape |  | 
        |  |