Embryo Flashcards
Prosencephalon gives rise to what?
Telencephalon
Diencephalon
Mesencephalon gives rise to what?
Midbrain
Rhombencephalon gives rise to what?
Metencephalon (Pons + Cerebellum)
Myencephalon (Medulla)
Where is the lateral ventricle located?
Telencephalon
Where is the third ventricle located?
Diencephalon
Where is the cerebral aqueduct located?
Mesencephalon
Where is the fourth ventricle located?
Between metencephalon and myencephalon
What week do the forebrain and hindbrain divide?
Week 5
Where do microglial cells derived from
Blood monocytes
What day does rostral neuropore close?
Day 25
What day does caudal neuropore close?
Day 27
Cervical flexure
Between hindbrain and spinal cord
Pontine Flexure
Divide hindbrain into metencephalon and myencephalon
Cephalic Flexure
Separates midbrain from forebrain (persists)
What weeks to basal ganglia develop
Week 6-23
Holoprosencephaly
Incomplete separation of cerebral hemispheres
*Associated with hypotelorism (close eyes), microcephaly, intellectual disability, pituitary dysfunction
Where does APG come from
Rathke’s Pouch (First arch ectoderm)
Surface ectoderm
Where does PPG come from
Neuroectoderm
What does the alar plate of the neural plate give rise to?
Dorsal horn; sensory fibers that stay within CNS
What does the basal plate give rise to?
Motor neurons that go to skeletal muscle
Preganglionic autonomics
Zone I of neural canal
[Ventricular Zone] Germinal Stem cells Ependymoblasts Ependymal Cells Choroid Plexus Cells
Zone II of neural canal
[Intermediate Zone]
Grey matter
Cell bodies
Astrocytes
Glioblasts
Zone III of neural canal
[Marginal Zone]
White matter
Oligodendrocytes
Axon tracts
Order of nuclei midline to lateral
GSE (3 4 6 12) GVE SVE (5 7 9) GVA/SVA SSA GSA
Medial to lateral orientation of nuclei in upper medulla
MOTOR
Hypoglossal nucleus
Vagal nuclei
Nucleus ambiguus
SENSORY
Vestibulococchlear nuceli
Solitary nucleus
Spinal Trigeminal
What plate gives rise to the cuneate and gracilis nuclei?
Alar plate (since they are both sensory- PCML tract!)
What side is more medial in the brain stem, motor stuff or sensory stuff?
Motor
What is derived from the basal plate in the Pons?
Facial motor nucleus
Trigem motor nucleus
Superior salivatory nucleus
Abducens nucleus
What are derived from the basal plate in the Midbrain?
Edinger-Westphal
Red nucleus
Oculomotor
Trochlear
What are derived from the alar plate in the Midbrain?
Superior colliculus
Interior colliculus
Spastic Cerebral Palsy
Damage to CST
Scissor Gait
Dyskinetic Cerebral Palsy
Damage to basal ganglia
Slow snake like movements
Ataxic Cerebral Palsy
Damage to cerebellum
Drunken sailor gait
Fall towards side of lesion
Chiari Type I
Present in adulthood
Associated with syringomyelia
Herniation of cerebellar tonsils through foramen magnum
- Lower cranial nerve issues
Chiari Type II
Present in infancy/childhood
Associated with spina bifida (meningomyelocele)
Herniation of medulla + cerebellum through the foramen magnum
Associated with hydrocephaly - due to blockage of cerebral aqueduct
Lower cranial nerve issues
Dandy Walker Malformation
Posterior fossa cyst, continuous with FOURTH ventricle
Hypoplasia of cerebellum, absence of vermis
Can also see GI/Heart problems
Hydraanencephaly
Absence of cerebral hemispheres, with membranous sacs
- Big heads
What is the order of cytodifferentiation of the Cerebrum?
Inside –> Out
Ventricular Zone
Preplate
Then axons grow inbetween and give rise to the intermediate zone
Where are the 2. neurons formed in the cerebrum cytodifferentiation?
Middle of preplate:
Marginal Zone
Cortical Plate
Subplate
What does Marginal zone of the preplate correspond to?
Lamina I
What does the cortical plate correspond to?
Lamina 5 and 6
Lissencephaly (Agyria)
Smooth brain due to failure of neuronal migration weeks 12-24
Order of Cerebellum development
ITS ALL NEUROECTODERM! :)
- Ventricular cells migrate towards Pia matter
- External germination center migrates up and around pia
- External germ cells migrate back down and in to form the granular layer
What tissue are schwann cells, autonomic ganglia, spinal ganglion cells and peripheral sensory neurons derived from?
Neural Crest
