Development of the CNS Flashcards
What is responsible for inducing neural plate development and when does it start?
Notochord
Approximately the 3rd week
What are the three vesicles that comprise the three vesicle stage of brain development?
Prosencephalon - forebrain
Mesencephalon - midbrain
Rhombencephalon - hindbrain
What vesicles does the prosencephalon give rise to?
Telencephalon
Diencephalon
Optic vesicles off of the Diencephalon**
What vesicles does the Rhombenecphalon give rise to?
Metencephalon - Pons
Myelencephalon - Medulla
What are the three layers of the neural tube?
Ventricular layer
Marginal layer
Mantle layer
Describe the mantle layer of the neural tube
Contains the primary neuronal cell bodies
Becomes gray matter of CNS
Describe the Marginal layer
Neuronal axons from the mantle layer
Becomes white matter of the CNS
What is the alar plate?
Portion of the developing spinal cord that contains dorsal neurocytes
Sensory development
What is the Basal plate?
Portion of the developing spinal cord that contains ventral neurocytes
Motor development
How are the alar and basal plates organized in the medulla?
Alar is oriented laterally
Basal is oriented medially
What two areas does the neural tube not close initially?
Anterior neuropore
Rhomboid fossa
What is the main function of the choroid plexus?
Produce CSF
Act as blood/CSF barrier
What two structures make up the Pons?
Tegmentum
Basilar pons
What is the cerebellum derived from?
Dorsal alar plate as cells migrate laterally and dorsally
What does the alar plate make up in the mesencephalon?
Layers of superior colliculus and nuclei of inferior colliculus
What does the basal plate make up in the mesencephalon?
Trochlear and oculomotor nucleui
What structures arise from the diencephalon?
Epithalamus
Thalamus
Hypothalamus
Subthalamus
All derived from various aspects of the alar plate**
What two structures come together to form the hypophysis?
Infundibulum
Rathke’s pouch
What is the most common cause of hypopituitarism in children?
Craniopharyngioma
A congenital cystic tumor that compresses the optic chiasm and hypothalamus
Remnant of Rathke’s pouch
What structures does the telencephalon make up
Cerebral cortex
Corpus striatum
What are the two parts of the cerebral cortex?
Neocortex - 6 layered
Allocortex - 3 layered
What are the two layers of the allocortex?
Paleocortex - olfactory
Archicortex - hippocampus
What does the corpus striatum give rise to?
Caudate nucleus
Putamen
Amygdaloid nucleus
Claustrum
Globus pallidus
What are the four components of the basal ganglia and the associated clinical disorder?
Caudate, Putamen, Globus pallidus, Substantia nigra
Neurodegenerative movement disorders such as Huntington’s and Parkinsons’s
What is the first critical period of neuronal development?
Rapid neuronal proliferation between the 4th and 6th month of development
Zika infects neural stem cells and reduces their number during this period
What is the second critical period of neuronal development?
Neuron process growth and formation of synaptic connections from 3rd trimester to 2 years
Astrocytes facilitate formation of synapses
Synaptic refinement
What is spina bifida?
Neural tube defect where posterior neuropore fails to close properly
What is spina bifida occulta?
Vertebral arch defect - least severe
What is meningomyelocele?
Most common variation of spina bifida typicall presen in Arnold-Chiari malformation
What is Meyloschisis?
Most severe form of spina bifida; no skin/meningeal covering
What is anencephaly?
Failure of anterior neuopore closure
What is encephalocele?
Skull fails to close/ ossify
Can result in hydrocephalus, limb paralysis, ataxia
What is Dandy-Walker syndrome?
Posterior fossa cyst leads to 4th vetrical dilation
What is hydrocephalus?
Excess CSF (from blockage of circulation or overproduction) leads to dilation of ventricles
What is holoprosenccephaly?
Post-neural tube closure defect that is caused by failed ventical development
What is a tethered spinal cord?
Spinal cord is attached to the spinal canal
Causes weakness and sensory deficits in lower extremities
