The Peripheral Nervous System Vid

 Today's video is the second of three excellent videos concerning neuropathy, delivered by Todd Levine. The first appeared yesterday and the third will appear tomorrow. They are absolutely worth watching, although you will need to settle down comfortably because they are 30 minutes long. They include information that is of value to everyone living with neuropathy; whatever the type and whatever the cause.


The Peripheral Nervous System
Todd Levine Clinical Assistant Professor, University of Arizona


  
https://www.youtube.com/watch?v=pcdKhKSLca8#t=18

The Human Nervous System Part Two

Today's post from helium.com (see link below) is the second part of a description of the human nervous system. Today's description is by a different author and you may notice one or two repetitions of information provided yesterday but that just helps to fix it in your brain. It's all very useful information and most certainly aids understanding of what your nervous system does and where it's going wrong if you have neuropathy. Both parts worth a read.
 

An overview on the human nervous system
by Jose Juan Gutierrez : Created on: October 23, 2011

 
The nervous system is the control center for all the processes occurring inside and outside of the human body, including all mental activity, such as learning, thinking, and memorizing. The nervous system monitors the organs, controls the movements of the muscles, processes data, and detects changes in temperature, among many other functions. The nervous system performs all these functions through the use of sensory receptors. Along with the endocrine system, the nervous system is responsible for maintaining homeostasis.

An overview on the human nervous system:

The nervous system is a communication network of nerve fibers, surrounded by a fatty substance known as myelin, and connective tissue that is constantly sending messages in and out of the human body. The complex activities performed by the nervous system include the motor, integrative, and sensory functions. The nervous system is classified into two subdivisions: the central nervous system (CNS), consisting of the brain and spinal cord; and the peripheral nervous system (PNS), consisting of nerves and ganglia (nerve cells outside the CNS).

The spinal cord and the brain form part of the CNS. The CNS is encased in bone for protection; the brain in the cranial vault and the spinal cord in the vertebral canal. The spinal cord is a long tube of nerve tissue that is located in the hollow channels of the vertebrae. The brain and spinal cord are surrounded by cerebro-spinal fluid (CSF) which protects the brain and spinal cord from injury. Membranes known as meninges prevent CSF from leaking to the outside.

The peripheral nervous system includes the nerve fibers that spread out from the spinal cord and the brain. These nerve fibers form the communication network between the CNS and the various organs of the body. The peripheral nervous system is subdivided into the somatic and the autonomic nervous systems. The somatic nervous system comprises the nerve fibers that connect to the skin and muscles and involves conscious activities. The autonomic nervous system includes the nerve fibers that communicate the CNS to organs, including the intestines, stomach, glands, and the heart, and involves unconscious actions.

Neurons are the nerve cells that carry out the functions of the nervous system; a neuron consists of a cell body (soma), a single axon, and one or more dendrites; neurons are classified as afferent, efferent, and inter-neurons; afferent (sensory) neurons carry signals from the peripheral sense receptors

to the CNS. Efferent (motor) neurons carry out signals from the CNS to organs, such as glands, or muscles. Inter-neurons (integration) neurons serve as connections between afferent and efferent neurons within the CNS.
Millions of sensory receptors detect changes occurring inside and outside of the body (sensory function); from the outside, they can detect changes, such as light, temperature, and sound; from the inside, they can detect carbon dioxide concentration, pH levels, and blood pressure. This information is known as sensory input; sensory input is changed into electrical signals (nerve impulses) which travel to the brain; once in the brain, these signals generate memory, thought, or decisions in a process known as (integration).

 

 Depending on the sensory input and integration, the nervous system reacts by signaling glands to secrete hormones, or muscles to contract; this is in response to an instruction from the nervous system, therefore, the muscles and glands are called effectors. This is known as the motor function of the nervous system.

Spinal reflex arc is a unit of the nervous system where responses to stimuli do not require conscious thought and as a consequence reactions occur more quickly than if the stimuli had travelled to the brain centers. There are two distinct types of reflex arc: one is autonomic reflex arc (having an effect on inner organs); and somatic reflex arc (having an effect on the muscles).

Al the systems in the human body are important to maintain the body in optimum functioning. The single movement of one leg involves the muscular, circulatory, and skeletal system; however it´s the nervous system which coordinates the activities of all these systems and without it, the human body wouldn´t be able to perform all its daily functions.

http://www.helium.com/items/2244685-an-overview-on-the-human-nervous-system

Basics Of The Nervous System In Simple Terms Pt 1

Today's informative post from sunlightinwinter.com (see link below) is the first in a series of articles by this author explaining how the nervous system works. As he says; we can research all we like but sooner or later we'll come across terms we don't understand. In the main, that's not a problem because, if we get the idea of an explanation, that can often be enough to help us learn to live with it but when it comes to the basics about nerves and their problems, we really should try to build up an information source, so that we can at least talk intelligently to our doctors about what is happening to us when it goes wrong. This article goes a long way to providing exactly that sort of resource and is well-worth a read.
 

Nervous System Basics (Part 1)
Posted on February 8, 2015 by sunlight in winter

As I’ve said time and time again, I really feel that people living with chronic pain/fibromyalgia can benefit immensely from learning about how the body works. Even the feeling that you are just beginning to understand the complex processes making up your experience of pain can help give you a sense of control over things.

And reading about the new research that is being done on pain, even if you don’t completely understand every word, can sometimes give you a reason to remain hopeful at times when you’re feeling stuck.

With that in mind, I’m going to back way up and publish a post I’ve been meaning to write for a very long time. Here I’ll outline a few key terms and concepts about how the nervous system works. Hopefully it will be helpful to anyone who is interested in learning more about pain.

So let’s get started.

The nervous system can be divided into two main branches.

The central nervous system consists of the brain and spinal cord, and is shown in pink in the diagram above.

The peripheral nervous system consists of all the nerves in the body, and is shown in yellow.

The brain is the command center for your body, and it is where your experience of pain is processed. It is where you think consciously, but it also controls many unconscious functions, such as breathing, your sense of balance, and the ability to orient your body in space.

The spinal cord is the relay system for messages between the brain and the peripheral nerves. (It can also play a role in affecting how strong your ultimate experience of pain is, but we’ll talk more about that later).

The peripheral nerves have two main jobs:

Sensory: Sensory nerves send signals to the central nervous system about what you are feeling physically. When you stub your toe or get a papercut, it’s sensory nerves that send that signal up your spinal cord to your brain.

Motor: This is (to me) a kind of funny scientific word. It really just means “movement.” The motor nerves of the peripheral nervous system are what tell your muscles to move, as well as tell your organs to perform specific functions.

Pain

When people talk about how pain works, they are generally talking about the relationship between the sensory nerves, the spinal cord, and the brain. The sensory nerves send signals up to the brain about any damage that may have occurred, and the brain decides how to interpret those signals.

But Pain is a Two-Way Street

Historically, people considered this pain pathway to be a very consistent, cut-and-dry system that always worked the same way every time. If a person was in a lot of pain, they had to have a lot of physical damage/injury. If they weren’t in very much pain, they must not have a very serious physical problem.

However, scientific advances in the past few decades have shown that pain is actually much more complicated than that. It turns out that the severity of a person’s pain does not always reflect accurately the amount of physical injury they have experienced.

You can have soldiers in battle who do not even realize they’ve been shot– their peripheral nerves are sending very strong messages of “damage” up to their brains, but their brains tune those signals out because they need to focus on survival.

Conversely, you can have people with chronic pain, who– due to a number of potential factors—can experience excruciating pain in response to a very minor injury, or in fact no injury at all.

Central Sensitization

At the risk of boring my long-time readers, let me define one of my most favorite terms again. Central sensitization is the process responsible for this last phenomenon, where people can develop an increased sensitivity to pain.

The term refers to a series of changes that can take place in the central nervous system (the brain and the spinal cord) which can ultimately make a person much more sensitive to pain. In some cases, central sensitization can become a self-perpetuating phenomenon, in which a person continues to feel pain long after their initial injury has healed.

Central sensitization is such a fascinating topic. There is still much research to be done on it, but so far it is believed to play a role in such seemingly-diverse conditions as fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, temporomandibular disorder, and many others.

One Last Thing

When I first started trying to understand the amazing, interesting new research that’s being done in pain, I kept hitting this one term that mystified me. The dorsal horn. What the heck is a dorsal horn? I was so confused by this for a long time, and it really held me back from understanding a lot of articles.

Turns out, the term dorsal horn refers to an area in the back of the spinal cord. The back of the spinal cord is where the sensory nerves meet with the spinal cord, so their messages can continue on up to the brain. It’s pretty simple actually– the sensory nerves connect with the back of the spinal cord, and motor nerves connect in the front. So when people talk about the dorsal horn, they are talking about where sensory information is entering the spinal cord and then being relayed on up to the brain.

For more info

If you want a really great overview of the divisions of the nervous system, I highly recommend this video.


Conclusion

I really hope you’ve enjoyed this post! As you can see, it’s written in a very different tone, and for a very different target audience, than my previous post. I’m still in the process of figuring out what type of post works best on this blog. I really want to be able to write about advanced scientific concepts for every day people, and I’ll probably be trying to figure out the best way to do that for a while. Your thoughts/comments/suggestions are always welcome, so please let me know if you have any! Thanks!

https://sunlightinwinter.com/2015/02/08/nervous-system-basics/

The HIV Virus Itself Can Attack The Nervous System At An Early Stage

Today's post from the always reliable sciencedaily.com (see link below) reports something that will be of no surprise to people living with HIV across the world and that is that neuropathy very often appears from the early stages of infection. This gives proof to the theory that the virus itself attacks the nervous system. The accepted knowledge is that neuropathy in HIV is linked to older toxic HIV drugs and doctors are still continually surprised that people arrive in their surgeries with neuropathic symptoms, despite being on the most modern HIV medication combinations. The study mentioned here claims that the symptoms appear pre-medication treatment and generally disappear after treatment begins. However, there has to be some considerable doubt about this claim! Neuropathic symptoms don't disappear and nerve damage is, at the moment, generally irreversible. People living with HIV generally see a worsening of their symptoms over a period of time and end up on the treadmill of drugs designed to suppress the discomfort but not cure it. Perhaps the most relevant finding of the study is that after contracting HIV, many people will show signs of nerve damage, with all the symptoms that we're familiar with. The idea that this is linked to the older drug regimes is somewhat outdated but not totally incorrect and modern HIV drugs can cause nerve damage too. The problem is that it's clear that the HIV virus itself attacks nerve cells and especially mitochondria and although HIV medications (old or new) don't help, they're not exclusively responsible for neuropathy in HIV patients.

Neurologic symptoms common in early HIV infection
Much more extensive, though milder than previously thought 
Date:June 13, 2016 Source:University of California - San Francisco

A team led by researchers from UCSF and Yale has found that half of people newly infected with HIV experience neurologic issues. These neurologic findings are generally not severe and usually resolve after participants started anti-retroviral therapy.

"We were surprised that neurologic findings were so pervasive in participants diagnosed with very recent HIV infection," said study lead author, Joanna Hellmuth, MD, MHS, clinical fellow in UCSF's Department of Neurology. "While the findings were mild, it is clear that HIV affects the nervous system within days of infection. Since the majority of these neurologic issues were resolved with treatment, our study reinforces recommendations that people at risk for HIV test often and start antiretroviral treatment immediately if they are infected."

The research will be published in the June 10, 2016, issue of Neurology, the medical journal of the American Academy of Neurology.

The team examined 139 participants in the RV254 Thai cohort who were recently infected with HIV. The time from infection to entry into the study ranged from 3 to 56 days with a median of 19 days. At this stage, participants would not test positive on the common antibody tests for HIV since they have not been infected long enough for a robust specific immune response to take place. Fifty-three percent had neurologic findings, with a third experiencing cognitive deficits, a quarter having motor issues, and nearly 20 percent experiencing neuropathy. Many experienced more than one symptom. One participant was diagnosed with Guillain-Barré Syndrome, the only severe case found in the cohort.

"In the early days of the epidemic in San Francisco, approximately 10 percent of patients with recent HIV infection presented with dramatic neurological disease. But that was likely due to patients coming in early because of the severity of symptoms they were experiencing. The Thai cohort has given us an opportunity to look at a broad range of newly infected patients, analyze their neurological functioning systematically and follow them over time. We are gaining deeper insights into the degree to which early HIV affects the nervous system," said study senior author, Serena Spudich, MD, Yale associate professor of neurology.

All participants were offered and commenced antiretroviral treatment at diagnosis. Ninety percent of the issues present at diagnosis were resolved after one month of treatment, but 9 percent of the participants had neurologic symptoms that were still not resolved six months after starting therapy. In addition, neurological symptoms were associated with higher levels of HIV found in participants' blood.

The study participants underwent extensive neurologic assessments. Self reported symptoms were correlated with objective neuropsychological testing. In addition, a quarter of participants opted to undergo a lumbar puncture and almost half of the patients agreed to undergo a MRI.

"This is one of the first comprehensive studies scrutinizing the involvement of the nervous system in early infection. Since we have been able to maintain the cohort for five years now, we will be able to study whether there are any persistent abnormalities that need to be addressed. Additionally, the ubiquity of symptoms in early infection found in this study reinforces the need for the brain to be considered as a compartment containing latent HIV as we design cure studies," said study co-author, Victor Valcour, MD, PhD, UCSF professor of neurology.

Story Source:

The above post is reprinted from materials provided by University of California - San Francisco. The original item was written by Jeff Sheehy. Note: Materials may be edited for content and length.

Journal Reference:
Joanna Hellmuth, James L.K. Fletcher, Victor Valcour, Eugène Kroon, Jintanat Ananworanich, Jintana Intasan, Sukalaya Lerdlum, Jared Narvid, Mantana Pothisri, Isabel Allen, Shelly J. Krebs, Bonnie Slike, Peeriya Prueksakaew, Linda L. Jagodzinski, Suwanna Puttamaswin, Nittaya Phanuphak, Serena Spudich. Neurologic signs and symptoms frequently manifest in acute HIV infection. Neurology, 2016; 10.1212/WNL.0000000000002837 DOI: 10.1212/WNL.0000000000002837

https://www.sciencedaily.com/releases/2016/06/160613105753.htm