Develops into the nervous system. Eventually forms the neural groove and the neural fold.Appears at the 3rd week.
Form from the neural plate within 20 days, become elevated and the ends fuse together forming the neural tube. The tube later forms the brain (rostral portion) and spinal cord (caudal portion).
Formation of the neural tube
Spina bifida occulta
Less serious form, the vertebral arch doesn't close--does not affect meninges, or cause deficits
Most common and serious form of spina bifida cystica- vertebral column lengthens and pulls on the cerebrum cutting off flow of CSF and causing hydrocephalus
Also known as a lipoma or lipocele- fatty tissue that can occur in spina bifida- extends thru the dura
Failure of the rostral neural tube to close- meninges can project thru the defect with our without brain matter. Causes motor, sensory and cognitive defects
Failure of neurocranium and brain to develop. Most common cause for stillborn births.
Differentiates in week 5 into the telencephalon (later becoming the hemispheres) and the diencephalon (becoming the thalamus, subthalamus, hypothalamus, and retina)
Midbrain- remains undivided
splits into two parts- the metencephalon (after brain) which becomes pons and cerebellum, and the myelencephalon (marrowbrain) which becomes the medulla
Theree flexures/bends occur in the neural tube- the cervical, pontine and the cephalic. The cephalic is most important and is responsible for the horizontal orientation of the brain and the vertical orientation of the spinal cord
Prosencephalon fails to divide- lose midline structures of the brain and face--worse case have single eye and nose. Impairments in feeding, cognitive deficits, MR, CP
Agenesis of corpus callosum
Partially or complete absence of corpus callosum with impairments in bilateral coordination, motor function, visual perception, MR, CP
Borders the cavity of the tube, consists of neuronal stem cells that eventually become neuroblasts
Surround the neuroepithelium which eventually becomes gray matter of SC
Surrounds the mantle layer and consists of axons. Becomes white matter when they become myelinated