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Questions tagged [peripheral-nervous-system]

The peripheral nervous system (PNS) is the part of the nervous system consisting of the nerves and ganglia outside of the brain and spinal cord.

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Why sympathetic and parasympathetic nerves originate in different parts of CNS?

Curious if there is a reason for having: parasympathetic nerves originating from brain stem and pelvic part of spinal cord sympathetic nerves originating from thoracic and lumbar parts It looks well-...
Stanislav Bashkyrtsev's user avatar
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Why electrical synapses are more common in invertebrates?

I suppose it's because they live in an environment where there's a constant vulnerability to predators and they need to respond quickly. But it's not really the case for many invertebrates and besides ...
Venkatesh Choudhary's user avatar
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Is it possible to make synthetic olfactory receptors?

Are there any electronic engineering technologies that allow people to make synthetic olfactory receptor that generate electrical impulses when exposed to certain proteins or molecules? If not, what ...
David's user avatar
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How does gold chloride stain neuromuscular junctions?

Gold chloride is used in muscle biopsies to stain the NMJ. What is the substrate that it binds to?
Polisetty's user avatar
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How is recruitment of multiunit smooth muscle cells fine tuned if they are innervated by varicosities?

In my physiology textbook (Silverthorn) and on wikipedia it says that: Multiunit smooth muscle tissues innervate individual cells; as such, they allow for fine control and gradual responses, much ...
SuperSpy's user avatar
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Why do muscle spindles send impulses at a constant rate when the muscle is at rest?

According to my book, the sensory neuron around the muscle spindle is sending impulses at a constant rate, while the entire muscle itself is relaxated (at rest). So when the muscle stretches the ...
mathomato's user avatar
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Why does botulinum toxin cause only NMJ symptoms?

Botulinum toxin acts by preventing release of ACh by cleaving SNARE proteins. But if it is acting on snare proteins shouldn't all vesicle releases be effected? Why is it limited only to the ...
Polisetty's user avatar
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Dorsal root fibres

How can dorsal root fibres be unmylinated though are responsible for conduction of pain and temperature? How is their conduction so fast without even being myelinated? Is presence of only one axon( ...
JM97's user avatar
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Confusion regarding the location of myelinated and unmyelinated nerve fibres

So, what I understand by neural system terms is Central nervous system [CNS]- consist of brain and spinal cord Peripheral nervous system [PNS] - consist of cranial and spinal nerves (all the nerves ...
Cerebral cortex 's user avatar
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Illustrating Action Potential Conduction and Ion-Gated Channels

I can separately illustrate action potential and ion-gated channels along an axon. However, I am not sure if I did the right thing on the picture below. What I'm trying to show are the simultaneous ...
thepajama's user avatar
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Parasympathetic effects on digestive tract - motility versus absorption

The parasympathetic nervous system's purpose is often referred to as "rest and digest." As part of this purpose, parasympathetic innervation increases motility in the digestive tract to move ...
Nicholas Hassan's user avatar
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Nervous stimuli and neurotransmitters and impacts

As far my knowledge, in body parts generally **acetacholine ** is the neurotransmitter. Which is responsible for most nervous impulses. Consider a body part, say, foot. Only one nerve reaches here. ...
Pranjal Rana's user avatar
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How do nerve impulses travel so quickly?

Nerve impulses must travel incredibly fast to achieve the functions they do. However, I have been taught that sodium ions move down the axons by diffusion (thus causing depolarisation of the next part ...
Laura kirkpatrick's user avatar
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Could a geomagnetic storm disrupt the functioning of nerves?

It is known that geomagnetic storms can cause power grid outages. Can they also disrupt the functioning of nerves/the nervous system?
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Do nerves grow out from within or in from the skin?

The Question: Do nerves grow out from within or in from the skin? Thoughts: My guess is outwards. However, I have a vague memory of a study involving frogs that I read about in a pop science book - ...
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Optic Nerve: neurons/area and bit rate?

Does anyone know the number of neurons adjoining a cross sectional area of the optic nerve and the theoretical bit rate of the nerve? I read that the ON cross sectional radius is 3-5 mm and the ...
Nick's user avatar
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Chains of ganglia on each side of the nerve cord belongs to the spinal cord

One of my textbook says this: "A double chain of ganglia on each side of the nerve cord belongs to the spinal cord." But the diagrams I saw on internet depict only one dorsal root ganglion. ...
Darshit ff's user avatar