Embryology 2 Flashcards
What are the final closures of the……
anterior and posterior neuropour
What are the secondary vesicles of the prosencephalon?
telencephalon
diencephalon
What is the secondary vesicle of the mesencephalon?
mesencephalon
What are the secondary vesicles of the rhombencephalon?
Metencephalon
Myelencephalon
What brain structures does the prosencephalon eventually form?
telencephalon
- cerebrum
Diencephalon
- thalamus, hypothalamus, epithalamus and retina
What brain structures does the mesencephalon eventually form?
midbrain
What brain structures does the rhombencephalon eventually form?
Metencephalon
- pons, cerebellum
Myelencephalon
- Medulla oblongata
What are the three initial brain flexures that occur in the 4th week?
neural tube bends to form:
1) midbrain flexure (between prosencephalon and mesencephalon)
2) Cervical flexure ( bet hind brain and spinal cord)
3) Pontine flexure (within hindbrain)
At what period of gestation does do the secondary vesicles develop?
5 weeks
How do the ventricles form from the neural tube?
neural canal within neural tube dilate to form ventricles
What do prosencephalon dilations create?
lateral and third ventricles
From what are the cerebral aqueducts formed?
Mesencephalon (caves inward to form smaller gap)
What structures are formed from dilation of rhombencephalon?
fourth ventricle
What is the innermost layer of the neural tube called?
Ependymal layer (made of neuroepithelial cells which are stem cells) - these cells give rise to neuroblasts (neurones) and glioblasts (astrocytes/oligodendrocytes)
What are the other layers of the neural tube?
Ependymal layer (innermost)
Mantle Layer
Marginal Layer (outermost)
- ependymal layer differentiates to form other layers
What are the plates which make up the mantle layer of the neural tube?
1) Alar plate (dorsal, sensory)
2) Basal plate (ventral, motor)
What are the mantle and marginal layers composed of?
mantle - cell bodies of motor neurones
marginal - axons of motor neurones
What are the four plates of the neural tube and what parts of the spinal cord do they become?
Roof plate - posterior median septum
Alar plate - dorsal gray columns
Basal plate - ventral gray columns
Floor plate - ventral medial fissure
What is Neurogenesis?
Process by which neurones and glia proliferate, migrate and are specified to form mature brain
What are the neuroepithelial cells?
Neuroblasts
Glioblasts
What is cell layering?
neuroblasts move toward periphery of neural tube following set patterns
How do glial cells migrate?
Move along the radial glial cells
How do somal bodies migrate?
Translocation is self directed
What occurs to neurones after elongation?
Synaptogenesis
- establishment of initial synapses
- which are constantly reconfigured throughout life
What is synaptic pruning?
- targeted elimination of functional synapses
