Development Of The Nervous System Flashcards
What is the embryological tissue origin of the central nervous system?
The ectoderm
Which process separates forms the neural tube and separates it from the rest of the ectoderm?
Neurulation
What process occurs to covert the neural plate into the neural tube?
Neurulation
The notochord arises within the mesoderm and induces invagination of the neural plate to form a separate tube called the neural tube.
Neural crest cells come from the dorsal part of the neural tube. What is their adult derivative?
Dorsal root ganglia Sympathetic ganglia Supra renal gland Preaortic ganglia Enteric ganglia
What defects of neural crest cell migration can occur?
Hirshprungs disease- aganglionic megacolon
Digeorge syndrome- thyroid deficiency, immunodeficiency, cardiac defects, abnormal facies
What is the sulcus limitans?
What does it divide?
What do the different parts do?
It is a fissure which divides the neural tube into an alar plate and a basal plate
Alar plate is dorsal, mainly sensory function
Basal plate is ventral- mainly motor function
What defect can arise from failure of the neural tube to close at the cranial end?
Anencephaly- incompatible with life
What defect can arise from failure of the neural tube to close at the caudal end?
Spina bifida. Most common in lumbosacral region.
What types of spina bifida exist?
Spina bifida occulta- missing vertebra- no other defect
Meningocoele- CSF only
Myelomeningocoele- CSF and spinal cord
What maternal blood marker can indicate a neural tube defect?
Raised serum alpha feto protein
What is commonly given to the mother during pregnancy to reduce the risk of neural tube defect?
Folic acid
After neurulation, the tube enlarges and can now be split into 4 sections. What are these and where are they relative to each other?
At the most cranial end- prosencephalon
Next most cranial- mesencephalon
Then- rhombencephalon
At the most caudal end- spinal cord
Which two divisions does the prosencephalon divide into?
The diencephalon and telencephalon
Which structure does the mesencephalon develop into?
Midbrain
Which two structures does the rhombencephalon divide into?
The metencephalon and myelencephalon
