Un-involvement of the nervous system in the body?

[icakeov]

This might be an obvious question, but is there any tissue functionality in the body that the nervous system is not involved or implicated in?

What I mean is, is there any process that doesn't need the nervous system's involvement and does its functionality independently and not related to it.

As far as I understand, the nervous system pretty much has its fingerprints on all the processes on some small level at least. And of course, the whole body is a system that functions together, but I thought I'd still throw this one out to see what the consensus is on this.

Any thoughts appreciated!

 

[berkeman]

Can you define exactly what you mean by "the nervous system"? Is the skeletal system innervated?

 

[icakeov]

I was looking up list of systems in the human body and Wikipedia defined nervous system as:
“Collects and processes information from the senses via nerves and the brain and tells the muscles to contract to cause physical actions.”
So I was a bit confused that that is as far as wiki would define the nervous system.

https://en.wikipedia.org/wiki/List_of_systems_of_the_human_body

 

[Ygggdrasil]

I can't really think of examples of how the nervous system would directly affect blood cells (and maybe even immune cells).

 

[DaveC426913]

Fingernails? The dead layer of the epidermis? Hair?

 

[jim mcnamara]

However - exocrine glands are derived from ectoderm, and can be considered modified nervous tissue. So if that counts then pancreatic hormones (like insulin) ( pancreas is considered both an endocrine and exocrine gland - a so called mixed gland) ) have effects without direct control. I admit this is really pushing it. A lot. But the question is kind of hard to answer,

You should consider learning about the development of tissues https://en.wikipedia.org/wiki/Human_embryogenesis
See day 12: ectoderm, endoderm, and mesoderm - those three tissues in the human embryo are the ultimate source of all of our cell types and tissue types.

 

[icakeov]

Very helpful answers, thank you everyone!
And a great pointer @jim mcnamara! Exactly what I was looking for!

 

[icakeov]

Also, even though neurons don't affect the blood cells directly, neurons move the muscles that pump the blood through the body. Mainly what was on my mind is whether there is any tissue system functionality in the body that is "independent" of its connection to the nervous system.

Nails growing could be one, they just grow without it being influenced by the nervous system, but then again, perhaps the nervous system influences the rate of growth.

So it is not specifically about whether bones contain neurons, but whether their movement would be rendered useless if there were no neurons to operate on that tissue and move it around for the body.

Hope this clarifies the question a bit more.

 

[jim mcnamara]

To be honest, I do not see what you want. Physiology is systemic - meaning you push on my belly button and five minutes later my left big toe hurts. That is an absurdist analogy of physiology. Which is what I think you are doing. There is a kind logical fallacy - Reductio ad absurdum - meaning you logically break things down enough to the point of a contradiction or an absurd conclusion, like I did with the belly button thing, to something that is a true and logically correct presentation - physiology is truly systemic. Do you see? You cannot draw conclusions any old way you want on a system that is extraordinarily complex. It loses meaning. I could be wrong but I am lost here.And stop to think. If our physiology was all that simple and hundreds of researchers (ones far smarter than you or me) cannot completely understand all of it after 200 years, it is a reasonable bet: physiology is very complex.

 

[icakeov]

You are totally right Jim, it did end up being quite an absurd question. If any tissue system functioned independently, that would just be a new organism.

I think what confused me was the "paired down" definition of the nervous system's function in the body, considering how involved with different parts of the overall organism it is, but I guess that could easily be said about any other tissue and organ system.

Thanks for indulging in what turned out to be a total cul-de-sac.

 

[BillTre]

I think what confused me was the "paired down" definition of the nervous system's function in the body, considering how involved with different parts of the overall organism

I agree, that's a rather limited idea of what the nervous system does.

Here is a wider view of nervous system functioning:
Reason for its existence: Without some effector function for the nervous system to control, there is no adaptive reason for there to be a nervous system (meaning it would not have evolved).

Actual nervous system cells (defined as neurons) can be found almost everywhere in the body. Neurons reside and project their axons to more places affecting more cells than just muscles. These actions are generally taken to be adaptive to the organism preforming them, helping them to survive and reproduce.
Included among nervous system locations and functions are:

• Control of muscle contraction is the most commonly understood function. This includes almost all muscles in the body. Striated skeletal (voluntary) muscles, smooth muscle of the GI tract, muscles of the iris (regulating the amount of light getting to the retina), muscle associate with hair follicles, etc.
  
• Hormonal output is also regulated to varying degrees by the nervous system. Some hormones are released directly from neuroendocrine cells in the hypothalamus. In other cases innervated organs can release hormones when properly stimulated.
  
• In some cases, the nervous system can directly control the sensitivity of sensor cells (in a sense making the sensory cell an effector of the nervous system in addition to being a sensory cell). An example of this is the feedback control to hair cells (vibratory sensors found in ears among other things) that can inhibit its responses to inputs.
  
• Circadian rhythms (recent Nobel Prize) have a large neural (as well as hormonal) component in its controls.
  
• Neural controls on some aspects of immune function are now know to exist.
• Control of blood vessels.
  
• Proprioceptive (sensing the body's states, functions, positions) functioning throughout the body (with a few exceptions).
• In lower animals, the nervous system is involved in developmental processes like regeneration (delivering growth factors to site of regeneration).

So it is hard to find something not involved with the nervous system.
Things like fingernail and hair (which can continue to grow for a while after bodily death) seem like good candidates.

 

[icakeov]

Great! That is super helpful! Thank you!

 

[BillTre]

I guess I should add some nervous system details, to better explain what I mean.
When I'm talking about the nervous system, I am talking about all of these as a group.

Nervous system parts:

1. CNS (central nervous system (brain and spinal cord, plus the retinas)
2. Periferal nervous system (neural elements not in the CNS); these can be grouped into:

1. Somatic: Things involved with the body movement and its regulation. Besides simply making a muscle contract. This would include both motor and sensory functions. Some sensory functions might be:
   
   1. establishing a position and orientation in space (lots of sensory inputs needed for this).
      
   2. knowing the position of each joint
   3. knowing the tension a muscle is under and using that in a feedback loop to control muscle contraction
   4. skin pressure
   5. tissue damage
      
   6. ...
2. autonomic nervous system: involved in controlling function of many "unconscious" functions of the nervous system (like hormone release, glandular functions, intestinal movements/digestion, ...). The autonomic nervous system will have and equivalent set of inputs to better direct the functioning of its set of effectors.

Nervous system cells:

1. Neurons (electrochemically active)
   
2. Support cells (glia or Schwann cells).

 

[256bits]

I was going to suggest fat cells would be a possible candidate, indirectly influenced by brain input, but then I found this.
http://www.the-scientist.com/?artic...nection-Between-Fat-and-the-Brain-Visualized/
which implies, as a quote,

“Lipolysis is another example of a basic process that occurs outside the brain that can be powerfully influenced by what occurs in the brain,” Kenny added. “The brain doesn’t function in isolation but communicates with other organs in beautiful ways.”

 

[ronronron3]

https://www.newscientist.com/articl...ur-nervous-system-could-let-us-defeat-cancer/

this is probably relevant to your post

 

[Laroxe]

Its possibly worth considering that the brain uses two messenger systems which are highly integrated. There are the nerves and the endocrine system, while nerves tend to have direct links to target tissues, hormones have a more varied and generalized effect. While the brain has a major role in controlling the release of hormones, hormones also effect the functioning of the nervous system, you can't really separate out the components and get any sort of understanding.