Brain Development Flashcards
What does the notochordal process induce formation of? With what molecule?
Neural plate
Sonic Hedge Hog (SHH)
When does primary neurulation occur?
Day 22-23
What neuropore closes on day 25?
Rostral neuropore
When does the caudal neuropore close?
Day 27/28
What parts of the CNS form during primary neurulation?
Brain => Lumbar SC
When does secondary neurulation occur?
Days 20-42
What forms during secondary neurulation?
Caudal eminence => Sacrum and coccyx
What germ layer do microglial cells arise from?
Mesoderm
What part of the neural tube forms the brain?
Neural tube cranial to 4th somites
3 primary brain vesicles
Proencephalon - forebrain
Mesencephalon - midbrain
Rhombencephalon - hindbrain
What primary brain vesicles divide in the 5th week?
Forebrain - Prosencephalon
Hindbrain - Rhombencephalon
What does the prosencephalon divide into?
Telencephalon
Diencephalon
What does the rhombencephalon divide into?
Metencephalon
Myelencephalon
What ventricles do the divisions of the prosencephalon contain?
Telencephalon - Lateral ventricle
Diencephalon - 3rd ventricle
What does the cervical flexure divide?
Hindbrain and spinal cord
What does the pontine flexure divide?
Divides hindbrain into caudal myelecephalon and rostral metencephalon
What does the cephalic flexure divide?
Midbrain and forebrain
When does development of the basal ganglia and cerebral cortex occur?
Between weeks 6 and 32
What does the metencephalon give rise to?
Cerebellum and pons
What does the myelencephalon give rise to?
Medulla oblongata structures - olive, pyramid
Incomplete separation of cerebral hemispheres during development can result in what disorder?
Holoprosencephaly
Patient presents with epilepsy, headache, abnormal movements. Upon examination, he has a reduced frontonasal prominence and a cleft lip as well as some developmental delay. What disorder does he most likely have?
Holoprosencephaly
What embryological layer gives rise to the anterior lobe of the pituitary gland?
First Arch ectoderm
What embryological layer gives rise to the posterior lobe of the pituitary gland?
Neuroectoderm
What part of the pituitary gland arises from the diencephalic floor?
Posterior lobe
What gives rise to sensory neurons that remain contained within the CNS?
Alar plate
What is the division between the alar and basal plates?
Sulcus limitans
What is the embryological origin of motor neurons that leave the CNS to go out to skeletal muscle?
Basal plate
What is the embryological origin of preganglionic autonomics?
What layer of the spinal cord are the ependymal and choroid plexus cells located?
Ventricular layer (Line the ventricles and central canal)
What cells are contained within the intermediate layer (mantle zone)?
Neurons
Astrocytes
Glioblasts => glial cells
What layer of the spinal cord are oligodendrocytes and the neuronal axons located?
Marginal zone
What are the GSE CNs?
3, 4, 6, 12 (midline)
What are the SVE CNs?
5, 7, 9, 10
What nuclei are located within the motor region of the upper myelencephalon?
Hypoglossal nucleus (most medial)
Dorsal motor vagal nucleus
Nucleus ambiguus
What nuclei are located in the sensory region of the upper myelencephalon?
Vestibular nucleus
Cochlear nucleus (most lateral)
Solitary nucleus
Spinal trigeminal tract and nucleus
What nuclei are located in the sensory region of the lower myelencephalon?
Cuneate and gracile nuclei
What nuclei arise from the alar plate in the metencephalon?
Cochlear nuclei
Vestibular nuclei
Solitary nuclei
Pontine nuclei
What nuclei arise from the basal plate in the metencephalon?
Abducens nuclei (most medial)
Facial motor nucleus
Trigeminal motor nucleus
Superior salivatory nucleus
What part of the mesencephalon does the alar plate give rise to?
Superior and inferior colliculi
What nuclei arise from the basal plates of the mesencephalon?
Edinger-Westphal nucleus
Red nucleus
Oculomotor nucleus
Trochlear nucleus
Spastic cerebral palsy is caused by damage to what?
Corticospinal tract adjacent to ventricles
Athetoid cerebral palsy is caused by damage to what?
Basal ganglion
Damage to the basal ganglion and VL thalamus can cause what disorder?
Dyskinetic cerebral palsy
Damage to the cerebellum can cause what kind of cerebral palsy?
Ataxic
What major structure is the caudate nucleus located adjacent to?
Lateral ventricle
What disorder is found here?
Syringomyelia/Arnold-Chiari Type 1
What disorder is syringomyelia highly associated with?
Chiari Type I
What levels are syrinx formations generally found?
C2-T9
Pt with a neurological disorder is seen walking on her toes with her knees and hips flexed. What disorder does she most likely have?
Spastic cerebral palsy
What is the difference between hemiplegia and diplegia?
Hemiplegia - affects both limbs on one side of body
Diplegia - affects lower limbs more than upper limbs
How would a patient with athetoid cerebral palsy present?
Slow, writhing movements of extremities and/or trunk
A patient with cerebral palsy shows incoordination, weakness, and shaking during voluntary movement. What kind is this?
Ataxic
20 y/o patient presents with headache, difficulty moving his tongue, and dizziness with decreased hearing. What disorder does he most likely have?
Arnold-Chiari Type 1
What disorder is found here?
Hydranencephaly
What structures are still intact in hydraencephaly?
Brainstem
During development, when does the cortex begin folding in on itself?
6th and 7th months gestation
What lamina appears largest in sensory areas?
Lamina IV (input from thalamus)
What lamina appears largest in motor areas?
Lamina V (output to subcortical structures: brainstem, spinal cord, basal ganglia)
Development of which laminae occurs first?
VI and V (deep layers from the cortical plate)
Which lamina is formed last?
Lamina II (from subplate)
Failure of neuronal migration during weeks 12-24 can result in what brain disorder?
Lissencephaly (agyria, smooth brain)
What is Lissencephaly characterized by?
Microcephaly
Ventriculomegaly
Minimal operculum of insula
Complete/partial agenesis of corpus collosum
Fetal brain injury by what microorganisms can cause microcephaly?
Cytomegalovirus
Rubella
Toxoplasma gondii
What are the layers of the cerebellum?
Pia mater
Cerebellar cortex
Molecular layer
Purkinje cell layer
Granular layer
White matter
Cerebellar nucleus
What is the embryological origin of the spinal ganglion cells and sensory neurons in the periphery?
Neural Crest Cells
What is the embryological origin of the motor neurons in the PNS?
Neuroectoderm
When does CNS myelination occur?
6th month gestation through puberty
When does PNS myelination occur?
4th month (motor before sensory)
What vitamin can prevent spina bifida?
Folic Acid