9/25 Development Of Nervous System - Dennis (Completed) Flashcards
What occurs in gastrulation? 5
Development of the three germ layers (Epiblast, Mesoderm, Endoderm)
What germ tissue does neuralation occur in? 6
Ectoderm
What induces induction of the neural tube (neurulation)? 6
The Notochord
Besides the neural tube, what does the PNS develop from? 8
Neural crest cells
Neuroectoderm
Ectodermal placodes
What are the two types of sensory sensations of the PNS? 9
Somatic sensory
Visceral sensory
What information does the visceral sensory collect? 9
nausea, hunger
Special —> smell, taste
What information does somatic sensory collect? 9
Touch, pain, pressure
Special —> hearing, equilibrium, vision
Where is the sympathetic and parasympathetic divisions found within? 10
Visceral motor of the efferent (motor) division of the PNS
What is the posterior region of the spinal cord dedicated to? 11
Sensory information
What is within the white matter of the spinal cord? 11
Lacks neuron cell bodies
Contains myelinated neuronal axons (tracts)
What is motor information processed by? 11
The anterior spinal cord
Where is the autonomic nervous system processed? 11
Lateral spinal cord
What is the Sulcus limitans? 12
An imaginary line we draw horizontally within a neural tube to show what will develop ventrally and what will develop dorsally within the organism
What are the three different lineages that neuroepithelium (neuroectoderm) can give rise to? 13
Apolar neuroblasts —> Neurons
Glioblasts:
—> astrocytes
—> oligodendroblasts
Ependyma —> epithelium of choroid plexus
What are the three different zones of the neural tube from the canal moving outward? 14
Ventricular zone (stem cells) —> mantle/intermediate zone (neuron bodies/glial cells & axons) Grey Matter —> marginal zone (neuronal axons)
What happens at the end of the 4th week within the mantle zone? 16
Mantle layer reorganizes into:
—> alar (dorsal) plates/columns
—> basal (ventral) plates/columns
What information do the dorsal horns of the alar plate carry? 17
Sensory information
What information do the ventral horns of the basal plate carry? 17
Motor information
What specifies motor neuron identity? 19
The varying [SHH] (sonic hedgehog)
Where is SHH secreted from? 19
The basal floor plate (supplied by the notochord)
What does a low [SHH] induce? 19
Multiple inteneurons induced
What does a high [SHH] induce? 19
Motor neurons induced
Once released from the basal floor plate, what does SHH target? 19
NKX2.2
NKX6.1
What counteracts the SHH gradient? 20
BMP/TGF-β signaling from the alar roof plate
What does BMP4 activate? 20
PAX3
PAX7
What is the role of PAX3 and PAX7? 20
Responsible for induction of the dorsal association
What will form first? Motor or sensory neurons? 20
Motor neurons
Where would you find intermediolateral cell columns? 21
T1 - L3
S2 - S4
What do the intermediolateral cell columns ultimately form? 21
The lateral horns
What do the lateral horns give rise to? 21
Autonomic nervous system
T1-L3 —> sympathetic division
S2-S4 —> parasympathetic division
Generally speaking what can we call PNS? 22
Anything that leaves the spinal cord or returns to the spinal cord
What are sympathetic ganglia? 22
Pockets of neuronal cell bodies that contributes to the sympathetic nervous sytem
What gives rise to the ribs and vertebrae? 23
Cranial sclerotomes
What is a GSE Nerve? 26
General somatic efferent (somatic muscle)
What is a GVE Nerve? 26
General visceral efferent (autonomic to smooth and cardiac muscle and glands)
What is a SVE Nerve? 26
Branchial or Special visceral efferent (muscles derived from the pharyngeal arches)
What is a GSA Nerve? 26
General somatic afferent (sensory in the skin, joint capsule, tendon, muscle)
What is a GVA Nerve? 26
General visceral afferent (sensory of visceral structures)
What is a SSA Nerve? 26
Special somatic afferent (hearing, balance, sight)
What is a SVA Nerve? 26
Special visceral afferent (taste & smell)
Where are neural crest cells for the sympathetic nervous system derived from? 30
Trunk and collateral ganglia
Ganglionic neurons
Where are neural crest cells for the parasympathetic nervous system derived from? 30
CN ganglia in the head and neck
Terminal ganglia in trunk
Ganglionic neurons
What myelinated in the CNS? What myelinated in the PNS? 32
CNS —> Oligodendrocytes
PNS —> Schwann cells
