Development PNS
19 important questions on Development PNS
What are the parts of the CNS and what are the parts of the PNS?
PNS: Cranial nerves & ganglia + Spinal nerves & ganglia + Autonomic nerves & ganglia + Enteric nervous system
What are cranial nerves?
What is a spinal nerve?
The spinal nerve starts when the dorsal and ventral tracts merge (mix of motor, sensory, and autonomous signals) and connects internal organs with the central nervous system.
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Spinal nerves are part of which nervous system?
How many pairs of spinal nerves are present in a human body?
What are autonomous nerves?
Autonomous nerves are part of which nervous system?
What is the enteric nervous system (ENS)?
What are the differences between the sympathetic and parasympathetic nervous system?
- Location of ganglia (sympathetic: close, parasympathetic: far)
- Origin of fiber bundles
- Neurotransmitter
- Sympathetic: fight or flight vs parasympathetic: rest and digest
What does develop into the CNS?
What does develop into the PNS?
Where does the sympathetic nervous system develop?
Where does the parasympathetic nervous system develop?
What does ectoderm become, what about mesoderm and endoderm?
Mesoderm becomes the muscles/skeleton.
Endoderm becomes needed for digestion, breathing, and the urinary tract.
What are the steps of development of the PNS?
- Formation sympathetic ganglia in week 5
- Somatic motorneurons bundle together and form the ventral root (day 30)
- Somatic, autonomous and sensory fibers bundle together form the spinal nerves
- Development of “sympathetic chain ganglia”
- The axonal tracts grow from the “sympathetic chain ganglia” towards their peripheral target organs
The development of motor and sensory neurons is organized in dermatomes (somatic innervation is organized in segments). What is a dermatome?
Each dermatome is innervated by sensory fibers of 1 spinal nerve although there is partial overlap between adjacent dermatomes.
What happens during the first step of PNS development, formation sympathetic ganglia?
- Neuronal migration from neural crest
- Emergence of “bilateral chain” of sympathetic ganglia
- Additional migration to facilitate development of prevertebral ganglia (collateral ganglia – lower abdomen)
- Additional migration to facilitate development of sympathetic organ plexi (heart, lungs and enteric system)
What happens during the third step of PNS development, somatic, autonomous and sensory fibers bundle together form the spinal nerves?
What happens during the fourth step of PNS development, development of sympathetic chain ganglia?
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