2.2 Development of nervous system Flashcards
What are the 6 cortices and lobes of the brain?
- motor (movement)
- somatosensory (receives sensory input)
- occipital lobe (vision)
- temporal lobe
- auditory cortex
- parietal lobe
What is neural induction?
assigning of neural potential to region of embryoW
What is neurulation?
formation of rudimentary nervous system
What is morphogenesis?
patterning of the neural tube
What is neurogenesis?
production of neurons and glia from precursor cells
What is neural migration?
neurons move from sites of production to their positions in the mature brain
What is axon growth and pathfinding?
neurons find appropriate targets for dendritic arborisation to occur
What is synaptogenesis?
refines and makes synaptic connections, followed by myelination
What are the steps of construction of NS?
- neural induction
- neurulation
- morphogenesis
- neurogenesis
- neural migration
- axon growth
- synaptogenesis
What layer of acquires neural fate?
dorsal ectoderm
What part of embryo is CNS formed from?
neural plate
How is epidermal fate decided?
through BMP gene. signals from organiser regions block BMP signals inducing neural fate
Where does gastrulation occur?
uterine wall after implantation
What occurs during neurulation?
neural plate folds fusing in the dorsal midline to form neural tube
What causes spina bifida/
neural tube does not close, neural tube zips up bi-directionally from initial points of closure
Where do neural crest cells originate?
cells at end of neural plate
What do neural crest cells give rise to?
peripheral and enteric NS ganglia
What causes the primary and secondary vesicles to form?
morphogenesis and patterning of neural tube after neural tube closes
What are the 3 main vesicles that form at cranial end of neural tube?
- prosencephalon (forebrain)
- mesencephalon (midbrain)
- rhombencephalon (hindbrain)
What are the 5 vesicles in the 5 vesicle stage?
- telencephalon
- diencephalon
- mesencephalon
- metencephalon
- myelencephalon
What doe the telencephalon become?
olfactory bulb, cerebral cortex hippocampus, striatum/basal ganglia
What does the diencephalon become?
thalamus and hypothalamus
What does the mesencephalon become?
midbrain
What does the metencephalon become?
pons and cerebellum
What does myelencephalon become?
medulla
What are three examples of moralising morphogens?
BMPS, FGF, Wnts
What does the notochord develop from?
mesoderm
How does dorsal and ventral regions of the brain form?
competing dorsalising and centralising morphogens in the neural tube
What determines if an area becomes an interneuron or a motor neuron?
closer to roof plate = interneuron
closer to floor plate = motor neuron
Which is the apical and basal side of the neuroepithelium?
apical - close to ventricles
basal - close to where spinal cord will develop
What is special about neuroepithelial cells and radial glia (hint: progenitor)
both are multipoint neural progenitor cells
Where are neural progenitor cells produced and where do they migrate?
produced in ventricular zone, as they develop, move towards basal surface
What do radial glia become?
astrocytes
What do symmetric divisions result in?
expansion of neuroepithelial layer or two identical daughter cells (neurons)
What do asymmetric divisions result in?
radial glia which divide and produce more radial glia and a differentiated neuron, so produce two different daughter cells
How do excitatory neurons grow?
inside out sequence
grow in dorsal and move towards surface of brain
How do inhibitory neurons grow?
come from MGE so produced in diff regions
Which comes first - neurogenesis or gliogenesis
Neurogenesis. They block each others actions.
Where does the information flow in neurons start and end?
Starts at dendrites, collecting electrical signals. Sends to cell body, generating outgoing signals to axon. Axon passes electrical signals to dendrites of other cel.
What is seen on the end of a growing axon?
Growth cone
What are pyramidal neurons?
Excitatory long range projection neurons. Axons project to other cortical hemisphere or spinal cord
What are interneurons?
Locally projecting inhibitory neurons which modulate cortical excitatory output
How many layers in the cortex?
6
What happens in dendrite and axon growth?
Repulsion of outgrowing axon caused by Sema3A and Slit1, attraction of main apical dendrite , elongation/retraction and branching of apical/basal dendrites
What do actin filaments do?
Regulate shape and directed growth of growth cone
What do microtubules do?
Provide structure
What do filopodia do?
Receive signals from environment to determine where to go
