Questions tagged [central-nervous-system]

The complex of nerve tissues including the brain and spinal cord, but excluding the peripheral nervous system.

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71 views

Is a corpse more flexible than a living person?

I read that the majority of humans have the muscular-skeletal potential to perform the splits that you see many gymnasts perform. The reason a living person with no flexibility training can not ...
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Frequency modulation of parasympathicus and sympathicus

According to my literature, the sympathetic nervous system accelerates heart rate and modulates < 0.1 Hz, whereas the parasympathetic nervous system decelerates heart rate and is modulated 0.04 - 0....
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21 views

Electrical transmission vs Chemical transmission

"The advantage of electrical transmission, apart from speed, is it can favour synchrony in firing. For example, in the brain stem a nucleus called the inferior olive can generate oscillations due to ...
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7 views

Nerves that supply the hip joint

From this page https://www.instantanatomy.net/leg/joints/hipnervesupply.html I understood that the hip joint is innervated by the femoral nerve because of the rectus femoris muscle And the sciatic ...
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14 views

What does it mean to say that the sympathetic nervous system is organized for diffuse activity?

"Sympathetic activities generally serve to mobilize the energy stores of the body, to increase the blood flow through certain regions (e.g., the heart) at the expense of other areas (e.g., the ...
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52 views

Why doesn't the spinal cord get thicker the further up we go?

The cervical and lumbar enlargements exist on the spinal cord as a result of the increased nerve input/output required for the arms and legs respectively. However, I don't understand how the ...
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Im struggling to see how these are presynaptic terminals/knobs and not post synaptic

How are these presynaptic terminals ? The action potential is generated at the axon hillock and moves down the axon (in this case to the right) , then at the end of the axon should be axon terminals ...
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42 views

Do multiple axons innervate a single skeletal muscle fiber?

The typical text-book illustration of innervation of muscle fibers shows branches at a single position along the fiber. Does any given muscle fiber have more axons that innervate it though, given that ...
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24 views

Is relative timing of signal transmission between neurons along axons and through synapses relevant in the brain?

A neuron may be part of a nerve connection between two endpoints, transferring a signal that is not very sensitive to variations in signal propagation speed. But a neuron inside a cluster of ...
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1answer
67 views

Does the cranial dura consist of the periosteum? and if not, then is there a mistake in my textbook?

My textbook (Neuroanatomy an illustrated colour text) states that: The spinal dura and much of the cranial dura are separate from the periosteum, which forms the inner lining of the surrounding ...
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23 views

Why does the cervical vertebrae contain more white matter than the more lower parts of the spinal cord?

Why does the cervical vertebrae contain more white matter than the more lower parts of the spinal cord, like the lumar vertebrae? In white matter are the axons of interneurons. Anyone know this?
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Does ingestion of alcohol with methylphenidate make it act more like dexmethylphenidate?

Methylphenidate (MPH) is a dopamine and norepinephrine reuptake inhibitor. It is the racemic mixture of d-MPH and l-MPH. According to the binding profile info on Wikipedia, based on studies, it is at ...
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137 views

What are these two nerves running parallel to the spine called?

I was looking for a human body nervous system, and often times i found a picture like the one below, where there are two nerves running parallel to the spinal column. I searched for it, but nothing ...
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56 views

Does the nature of nervous impulses give us a finite number of things we can perceive?

This is a subject that is very disturbing to me and one that I've been obsessing over for years. I warn you now that this is probably not the sort of thing you get asked on this website and I'm not ...
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58 views

How does (action potential) hyper-polarisation work?

I understand that after depolarisation, repolarisation and then hyperpolarisaiton occurs and that an area in hyperpolarisation is in its "refractory period". Why does this prevent Na+ ions diffusing "...
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99 views

Why are spinal nerves considered a part of PNS while the spinal cord is a part of CNS?

So from my common understanding, CNS consists of brain and spinal cord, and PNS consists of everything else. But the spinal nerves - the nerves connected to the spinal cord - why are those considered ...
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Why are higher doses of atropine required to produce central effects?

Reason given in my book is restricted entry into the brain..is it something to do with the chemisty?
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15 views

Mild introduction to selective advantage of intelligence/nervous systems in animals?

I have a general understanding of why intelligence, i.e. nervous systems in animals, is advantageous: processing information allows an animal to adapt to its environment dynamically and perform ...
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1answer
1k views

Why is the hippocampus considered to be a cortical structure but not the amygdala?

I'm having some trouble understanding the anatomical differences that classify the hippocampus as a cortical structure but not the amygdala. I have included the screenshot of a diagram from Gray's ...
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41 views

Results of self-administration study about pain in honeybees?

There research on nih.gov about ability of bees feel pain. But I can't understand their conclusion. Could you provide necessary excerpts here from those study so it would be clear what conclusion they'...
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Any known values of density for spinal cord (pig or human)?

Need to know the density of spinal cord tissue to evaluate the shear modulus from ultrasound elastography (shear wave velocity) measurements, but need the density of the tissue to compute this. I am ...
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313 views

Is it possible to Interpret Nerve Signals As to Where They Are Going In The Human Body And What Their Task Is? [closed]

I have recently watched some anime, (yes, anime, probably a huge cause to lots of questions asked on the internet), and it got me thinking. We can intercept nerve signals throughout the body, but ...
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584 views

Why do nerve gas victims have chronic neurological issues?

The article on Wikipedia says the following: The effects of nerve agents are long lasting and increase with continued exposure. Survivors of nerve agent poisoning almost invariably suffer chronic ...
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If motor neurons are part of the CNS, what is the PNS made of? [closed]

It is my understanding that motor neurons transmit messages to the myocytes of skeletal muscles all over the body. This should make them part of the peripheral nervous system that transmits both the ...
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153 views

Does GABA help or hinder anxiety?

This article https://www.prnewswire.com/news-releases/smartphone-addiction-creates-imbalance-in-brain-300558945.html Says both The researchers performed MRS exams on the addicted youth prior to ...
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368 views

Are all cone cells connected directly to the brain?

Coming from a computing science background, I noticed that cameras have orders of magnitude fewer wires than pixels. For example, the Raspberry Pi Camera v2 has 8 megapixels, but only 10 wires ...
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191 views

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 ...
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3answers
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Why are some neurones unmyelinated?

As far as I am aware, most of the central nervous system consists of myelinated axons and most of the peripheral consists of unmyelinated. What is the reason for this? Would it not be more ...
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133 views

An introduction to nuclei in the pons?

I have a couple of questions regarding the nuclei in the pons, thus I figured it would be best to frame the main question in the way that I did. My main question, however, is whether the basal pontine ...
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136 views

Why are “itch signals” transmitted so slowly from the skin to the human brain?

In the second half of the BBC radio (and podcast) program Cats and Itch; Discovery, The Curious Cases of Rutherford and Fry Episode 2 of 5 the phenomenon and origin of the "itch" and related ...
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233 views

Alcohol consumption and central nervous system

After alcohol intake, the cerebrum related functions like vision and speech is affected first and later on there's problem with the cerebellar functions like balancing and hand-eye coordination. My ...
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43 views

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. ...
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52 views

Seizures and blood pressure

A seizure is basically a synchronized firing of neurons as opposed to the more common unsynchronized firing taking place during normal neural activities. However, I am uncertain if the exact technical ...
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96 views

Electric Shock To Human Body [closed]

What happens in our body when we get an electric shock?
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111 views

Neurons during Numb feeling

We become numb when there is short supply of blood to some parts, as mentioned here. If that is the reason, why don't neurons and other cells die at that part if they don't receive oxygen and other ...
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How do our eyes detect light at different frequencies?

Here is my confusion: we can see colored light of different wavelengths: form red to violet. To my understanding, these stimuli cause a confirmational change in the photoreceptors in our eyes and ...
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3answers
6k views

Do lobsters possess a nervous system to feel pain?

I was reading an article, which it mentions that lobsters do not have a nervous system: Lobsters have very poor eyesight and no nervous system. They walk slowly on the sea floor but are capable ...
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Is the bipolar neuron of the retina considered a sensory neuron?

Any neuron that participates in sending impulses from receptors to CNS are referred as sensory neurons. But I often see bipolar neurons of eye(which according to the above definition should be sensory ...
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2answers
110 views

At what stage is the nervous system developed enough to interpret neuronal signals as 'pain'?

According to this article in Live Science, one of the reasons the fetus can't feel pain until 19 weeks is because the nervous system isn't fully developed. But according to this article, the heart ...
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1answer
721 views

How a nerve impulse reaches the correct destination?

Say your brain wants to retract your right hand. If there is some information coding playing a major role here, then what is the mechanism to find the correct path to reach the correct muscle? Or is ...
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4answers
8k views

Are there organisms with fewer than 1000 neurons?

I'm developing neural networks comprised of just 3 to 10 layers of virtual neurons and I'm curious to know if there are any insect brains out there with fewer than a thousand neurons? Are there any ...
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4k views

Why is bacterial meningitis worse than viral meningitis?

My field is not biology related, but it is commonly said that bacterial meningitis is far more dangerous to the individual than the viral kind. It seems to be true even with antibiotic treatment. What ...
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238 views

Why are interneurons needed in the spinal cord for polysynaptic reflexes and somatosensory tracts to the brain?

The single explanation I found for the polysynaptic reflex is that the interneuron diverges into more pathways, such as the efferent motor neuron, the inhibitory neuron to the opposite extensor muscle,...
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2k views

Differences in the action of Scopolamine and Atropine

Both Scopolamine and Atropine are muscarinic antagonists, having essentially the same action: blocking parasympathetic nerve receptors. The action on the brain by muscarinic antagonists is presumed ...
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1answer
80 views

Photoreceptors and light with mixed frequencies

I am interested in how the activation of a, say, blue cone depends on the incident light. Wikipedia tells me this: , which describes how strong the activation of the blue cone is for light with a ...
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505 views

Can low temperatures induce a withdrawal reflex?

I read in "Essentials of Pathophysiology: Concepts of Altered Health States By Carol Porth" that "The thermal pain receptors are stimulated only by extremes of temperature such as "freezing cold" ...
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695 views

Why is Capsaicin injection not used instead of nerve surgeries for pain?

High concentration capsaicin kills c & a-delta nerve fibers permanently or at least long term. This has been known for 30 years. But capsaicin is only used in creams and patches, and not for ...
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950 views

Do all nerves in the body end at the tongue? [closed]

I saw this someone but have searched on google to affirm or deny it, but didnt find anything on all nerves ending in the tongue. Please help
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Is the CNS vascularized?

I was under the impression that the CNS is never penetrated by blood vessels, which explains why one never sees them in histological samples. However a google search reveals I am wrong. So can ...
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2k views

What would happen if nerves didn't have refractory period? [closed]

What would happen if nerves didn't have refractory period? And, what part of his nervous system or neurons are not needed?