W5 Nervous system structure through development Flashcards
Neural plate
17 days
Endoderm = viscera lining,
Mesoderm = bones and muscles.
Ectoderm = skin and nervous system (neural plate)
Neurulation (22days)
Neural plate curves and forms a neural tube. Neural tube becomes every cell in the CNS. And the neuronal crest becomes the PNS.
Somatic nervous system
voluntary control, moves all of our muscles. Innovation of things coming from the soma (the neural tube)
What neurons form from the nerual crest?
Sensory neurons whose cell bodies lie in the dorsal root ganglia (spinal cord).
Autonomic neurons ( post ganglionic parasympathetic neurons, enteric neurons)
Not neurons but other cells such as chromaffin cells and Schwann cells derive from the neural crest.
Why are women advice to take folic acid when trying to conceive and during pregancy
Failure to appropriately close the nural tube, specific sequence of gene expression adn influened by environement, folic acid = reduces 90%. Because it influences DNA synthesis.D
Differentiation
Different parts of the neural tube differentiated. At the rostral face more differentiation because the forebrain is very complex. Separate into 3 primary brain vesicles.
Differentiation- 3 primary brain vesicles
Separate into 3 primary brain vesicles:
Rostral = prosencephalon or forebrain.
The middle of the neural tube = midbrain or mesencephalon
Caudal part of the neural tube = hindbrain or rhombencephalon
Motor neuron
Efferent transmission
Sensory Neuron
Afferent Transmission
Forebrain differentiation
White matter = coming in and out of the brain. Corpus callsum = huge white matter tracked, connects both hemispheres, feeding information from one to another.
Midbrain differentiation
Midbrain = has the cerebral aqueduct. Tectum = dorsal aspect of midbrain. Tegmentum in the middle. Huge white matter tracks bring information from motor cortex to the spinal cord.
Superior colliculus = in vision
Hindbrain differentiation
Cerebellum formed by the rhombic lips. (rostral part of the hindbrain)
Medulla pyramids form at the front.
Cerbellum
Co-oridnatin of movement, balance, posture. 10% CNS volume, 50% CNS neurons.
Vestibulocerebellum = oldest, balance. Spinocerebellum = muscle stretch receptors. Cerebrocerebellum = projections from sensorimotor cortex = motor coordination.
The cerebral cortex = 3 types
Hippocampus, Olfactory, Neocortex.
Hippocampus
(first developed) = memory, if you sense chemical you want to remember not to go to it again (survival) found in each temporal love memory, only 3 layers.
Olfactory cortex
= receives sensor information. (Smells), when we sense chemicals around use, the information gets sent to this cortex. (even in primitive animals, for survival (food or poison?) (simple, bellow the hippocamps (orange and green)
Neocortex
= (new ish, all mammals have the neocortex, part of the brain that differentiates between animals’ mammals) = the neocortex is far bigger than other animals. (not just survival)
Neocortex is divided into
into different lobs. Looks for key gory and sulci
lateral sulcus + central sulcus + parieto-occipital sulcus
Frontal lobe, Temporal lobe, occipital love, parietal lobe.
The neocortex has 6 layers
Layers = the exact structure of these layer different between regions of the neocortex.
Thin layer, clinging to the whole brain = Pia
Molecular layer = just dendrite and axons, but no cell bodies (lots of synapses.)
Example of Layers in the Neocortex
Ext. Granular layer, Ext Pyramidal layer, Int. Granular Layer, Int. Pyramidal Layer (often larger than the other layer, larger cells), Fusiform Layer = cellular layers