Neurology Development Flashcards
Describe, in words, the development of the nervous system.
notochord induces overlying ectoderm to differentiate into neuro-ectorderm and form the neural plate. the neural plate gives rise to the neural tube and the neural crest cells (the neural plate rolls up in neurulation). the notochord becomes the nucleus pulposus of the intervertebral disc in adults.
What is the time line for early neural development?
Day 18: you start to get neural plate and notocord.
then, the neural. Neurulation happens soon thereafter (neurulation = rolling up neural plate)
By day 21, primary neurulation should be complete and neural crest cells are allowed to go out
Alar plate vs. basal plate
alar plate: dorsal, sensory
basal plate: ventral, motor
this is the same orientation as the spinal cord
What are the 3 primary vesicles of the developing brain?
the forebrain (prosencephalon), the midbrain/mesencephalon, and the hindbrain/rhombencephalon
What are the secondary vesicles of the developing brain? Where do they come from?
forebrain/prosencephlon goes to 2 lobes of telencephalon and the diencephalon
midbrain/mesencephlon: stays mesencephalon
hindbrain/rhombencephalon: metencephalon and myelencephalon
Adult derivatives of the telencephalon
walls: cerebral hemispheres; cavities become the lateral ventricles
Adult derivatives of the diencephalon
walls: thalamus; cavity: third ventricle
Adult derivatives of the mesencephalon
walls: midbrain; cavity: aqueduct
Adult derivatives of the metencephalon
walls: pons and cerebellum
cavity: upper part of 4th ventricle
Adult derivatives of the myelencephalon
the medulla
cavity becomes the lower part of 4th ventricle
What does the neuroectoderm become?
CNS neurons, ependymal cells (which form the inner lining of the ventricles and make CSF), oligodendroglia, and astrocytes
What are the key neural crest derivatives?
PNS neurons, Schwann cells.
melanocytes, tracheal and laryngeal cartilage, enterochromaffin cells, parafollicular cells, (odontoblasts)
What are key nervous system components derived from mesoderm?
microglia (much like macrophages)
What are neural tube defects? When do they occur? What are the associations?
this describes a condition in which neuropores fail to fuse during the 4th week of development. This causes a persistent connection btw the amniotic cavity and the spinal canal. It is associated with low folic acid intake before conception and during pregnancy.
What are some findings associated with neural tube defects?
elevated alpha fetoprotein in amniotic fluid and maternal serum. High acetylcholinesterase in amniotic fluid is a good confirmatory test, as fetal AChE in the CSF is able to flow freely across the defect into the amniotic fluid.
