Lecture 2-NS Development Flashcards
Which process produces the notochord?
Gastrulation
What does the notochord induce?
Neurulation -> neural plate
What is the depressed mid-region of the neural plate called?
Neural groove
How is the neural tube formed?
Neural folds approach each other in the midline and fuse
What is the notochord?
Solid rod of cells running in the midline which directs the conversion of overlying ectoderm to neurectoderm
What is anencephaly?
Anterior neuropore doesn’t close -> no brain
What is spina bifida?
Posterior neuropore defect
Where does spina bifida most commonly occur?
In lumbosacral region
What are the two forms of spina bifida?
- meningocoele: only meninges herniate, hydrocephalus
- myelomeningocoele: meninges, bone and parts of cord herniate + hydrocephalus -> neurological deficit due to neuronal tissue in cyst
What is rachischisis?
Failure of neural fold elevation -> splayed nervous tissue across the surface of the embryonic back
How are NTDs diagnosed?
- raised maternal serum alpha fetoprotein
- USS
How can NTDs be prevented?
Folic acid
Describe how the cauda equina forms
- Neural tube gives rise to spinal cord
- at 3rd month, spinal cord is same length as vertebral column but after, vertebral column grows after
- spinal roots must elongate because they exit at intervertebral foramen -> cauda equina
What are the three primary brain regions formed during neurological fold formation?
- forebrain = prosencephalon
- midbrain = mesencephalon
- hindbrain = rhombencephalon
Which secondary brain vesicles form from the prosencephalon and what are their derivatives?
- telencephalon -> cerebral hemispheres
- diencephalon -> thalamus
Which secondary brain vesicles form from the mesencephalon and what are their derivatives?
Mesencephalon -> midbrain
Which secondary brain vesicles form from the rhombencephalon and what are their derivatives?
- mesencephalon -> pons, cerebellum
- myelencephalon -> medulla oblongata
What are flexures?
When neural tube folds up as it runs out of space to grow
Where is the cervical flexure?
Spinal cord - hindbrain junction
Where is the cephalic fixture?
Midbrain region
What is the role of the ventricular system?
To cushion the brain and spinal cord within their bony cases
How can spina bifida be treated?
Shunting fluid into abdominal cavity
Describe the organisation of the neural tube from the inside out
- neuroepithelial layer
- intermediate (mantle) layer: neuroblasts
- marginal layer: processes
True or false: the alar plate is responsible for motor function
FALSE - sensory (basal is motor)
