Development of Nervous System Flashcards
What does the neural tube form?
the CNS, neural plate, neural fold, neural groove
Embryonic ectoderm becomes what on the body?
skin
What does the neural crest become?
PNS and ANS
Cranial 2/3 becomes what?
future brain
Caudal 1/3 becomes what?
spinal cord
How many days does it take for the cranial/rostral neuropore to close?
25 days
How many days does it take for the caudal neuropore to close?
27 days
The walls of the neural tube are initially composed of what?
pseudostratified columnar
What is the sulcus limitans?
- differential thickening of lateral walls
- separates alar and basal plate
The neuroepithelial cells constitue what zones?
- intermediate
- ventricular
- marginal
What is the intermediate zone?
- contains alar and basal plates
- gray matter
What is the ventricular zone?
gives rise to macroglial cells and neurons
What is the marginal zone?
- consists of outer parts of neuroepithelial cells
- becomes white matter
What is the process for the formation of neuroblasts?
- mesenchymal cell -> microglial cell
- apolar neuroblast -> neuron
The alar is responsible for what neurons and forms what horn of the spinal cord?
sensory; dorsal
Where does the conus medullaris end on an adult and at birth?
- birth: L3
- adults: L1-L2
Schwann cells are derived from what cells?
neural crest cells
Oligodendrocytes are derived from what?
neural tube
What is spina bifida occulta?
- most common
- unfused arch
- occurs at L5/S1
- presents with small dimple and tufted hair/dermal sinus
What is spina bifida meningocele?
- unfused arch
- meninges
What is spina bifida meningomyelocele?
- unfused arch
- meninges
- spinal cord
What is spina bifida myeloschisis?
- most severe
- spinal cord is open
- neural folds failed to close
- results in permanent paralysis/wekness in lower limbs
What is dermal sinus?
failure of surface ectoderm to detatch from neuroectoderm and meninges that envelop it
The lumen of neural tube becomes what?
brain ventricles
What is the path of the forebrain (prosencephalon)?
- telencephalon> cerebral hemispheres> lateral ventricles
- diencephalon> thalami> 3rd ventricle
What is the path of the midbrain (mesencephalon)?
mesencephalon> midbrain> aqueduct
What is the path for the hindbrain (rhombencephalon)?
- metencephalon> pons and cerebellum> upper part of 4th ventricle
- mylencephalon> medulla> lower part of 4th ventricle
What is the neurohypophysial diverticulum in pituitary gland development?
- neuroectodermal downgrowth from diencephalon
- forms neurohyphysis
- post. pituitary
What is the hyperphysial diverticulum in pituitary gland development?
- ectodermal upgrowth from stomodeum
- forms adenohypophysis
- ant. pituitary
What is the role of the pontine flexure?
divides hindbrain into metencephalon and mylencephalon
What is the special somatic afferents?
sense of balance and gravity
What is the special visceral afferents?
“special sense” taste and olfaction
What is the special visceal efferents?
skeletal muscles of branchial arch origin
What does the ventral portion of the metencephalon include?
pons
What does the dorsal portion of the metencephalon include?
cerebellum
The roof of the 4th ventricle include what?
- choroid plexus
- 3 foramina: foramen of Luschka (2) and foramen of Magendie
What is the cranial most extent of the sulcus limitans?
mesencephalon
What does the lumen within the mesencephalon include?
cerebral aqueduct
What is the end of the neural tube?
diencephalon
What do the lateral walls of diencephalon contain?
thalamus, hypothalamus, epithalamus
The nuclei within the diencephalon is composed of what?
alar lamina
The rostral wall is formed by the what?
lamina terminalis (cranial most end of the original neural tube)
The lumen of the diencephalon is what ventricle?
3rd
What does the telencephalon form?
cerebral hemispheres and lateral ventricles
Where is the telencephalon located?
on either side of diencephalon
What is cranial meningocele?
meninges with CSF
What is meningocephalocele?
- meninges with CSF
- portion of cerebellum
What is meningohydroencephalocele?
- meninges with CSF
- portion of occipital lobe
- portion of post. horn of lateral ventricle
What is the hydrochalus disease?
- excess CSF
- enlargement of the head
What is merocephaly disease?
forebrain, midbrain, most of hindbrain is absent
What is microcephaly disease?
reduction in brain growth but face is normal size
