The Nervous System in Relation to Neuropathy

We know that neuropathy is a disease of the nervous system and have a rough idea that it's to do with the disruption, or breakdown of signal paths, thus creating all the symptoms that we're well aware of - short circuits in the system, that sort of thing. However, what do we really understand when we are told we have a neurological disease? What do the nerves actually do and why do they stop working as they should wwhen we get neuropathy?

This article from Medifocus Health (see link below)gives an excellent explanation of exactly how the various nerves in our bodies work and what goes wrong when we suffer from neuropathy. Very much worth a read.

The Nervous System

The nervous system controls the smooth functioning of all systems in the body as well as all interactions between the human being and the environment. It consists of two networks:





•Central nervous system - includes the brain and spinal cord

•Peripheral nervous system - includes the nerves that lead from the brain and spinal cord to all parts of the body. This is the system affected by peripheral neuropathy. There are two components to the peripheral nervous system:

◦somatic nervous system - regulates body movement through control of skeletal muscles and connects the brain to the outside environment through the five senses. It is the "voluntary" nervous system that enables people to react to environmental stimuli.

◦autonomic nervous system- controls automatic, involuntary functions including heart rate, blood pressure, breathing, digestion, and bladder function. This system is responsible for maintaining homeostasis, the state of equilibrium where all body systems are working and interacting correctly.

An extensive system made up of three types of specialized nerves makes up the peripheral nervous system:

*Motor nerves - carry messages from the brain to organs, muscles, and glands, and are responsible for the ability to move any part of the body. These are called efferent nerves. * Sensory nerves - carry information from organs (e.g., the skin) to the central nervous system where it is processed into sensation (e.g., touch, temperature changes, and vibrations). These are called afferent nerves. * Autonomic nerves - control involuntary functions such as heart rate, digestion, respiration rate, and perspiration.

Each peripheral nerve cell (neuron) in the human body has three parts:

•Cell body (also called soma), which is similar to the cell body of all other cells.

•Dendrites - fibers of varying sizes which extend from the cell body and are the sensory terminals of the neuron. They receive messages from neighboring cells and transmit them to the cell body.

•Axon (also called a nerve fiber) - a long slender projection that extends from the cell body and transfers a signal from the cell body to another nerve or muscle cell. Axons can be either myelinated (insulated by the myelin sheath made up of specialized cells) or unmyelinated. The presence or absence of myelin affects the speed of transmission of impulses; conduction speed is significantly faster in myelinated cells.

Nerve fibers may be either large or small.

Large Nerve Fibers

Large fibers are long nerve fibers that are myelinated and enable very fast conduction of impulses to the brain and spinal cord. They carry non-nociceptive information and are not normally associated with pain. Lesions or injury to large fibers can affect many functions including:

•Motor function
•Vibration perception
•Positional sense
•Perception of temperature

Symptoms associated with large fiber neuropathy include:
•Numbness
•Tingling
•Weakness
•Loss of deep reflexes

Small Nerve Fibers

Small nerve fibers may or may not be myelinated and each type involves different sensations. Regardless of whether or not they are myelinated, they contain nociceptors which are highly sensitive to pain and paresthesia (abnormal sensations such as tingling, pricking, or burning).

Symptoms of small fiber neuropathy are many and include:

•Pain described as burning, stabbing, prickling, jabbing, or lancinating (piercing)
•Sensation of "broken glass", "burning sand", or "ice pick in the bone"
•Tight band-like pressure
•Insensitivity to heat and cold
•Autonomic dysfunction (malfunctioning of the autonomic nervous system)

While small fiber neuropathy may be caused by conditions such as diabetes or HIV, the cause of most cases of small fiber peripheral neuropathy is unknown and is called idiopathic peripheral neuropathy. It is estimated that an underlying cause for small fiber neuropathy is found in less than 10% of patients. Small fiber neuropathy is the most common type of PN in people over the age of 50 and is often unrecognized by physicians. It is very painful to the point of being debilitating and responds slowly to medication, if at all.

In peripheral neuropathy involving both large and small fibers, small fiber damage usually precedes large fiber dysfunction and occurs typically in the lower limbs.

http://www.medifocushealth.com/NR021/Introduction-to-Peripheral-Neuropathy_The-Nervous-System.php

The Effects Of HIV On The Nervous System

Today's short post from nurseuncut.com.au (see link below) sums up the concerns of many people living with HIV that they will end up with neurological problems as a result. Certainly during the first years of the plague, many patients moved rapidly towards severe neurological problems but with the improvements in medication, that is now far less often the case. The article refers to neuropathy as a 'mild neurological abnormality'; something that many neuropathy patients may take issue with but when compared to dementia, Alzheimers etc maybe you could argue that neuropathy is the lesser of many neurological evils. Following the link in the last paragraph will provide a lot more information on the subject.

Positive living with HIV
Posted on December 12, 2012 by NU_admin

Guest post by Adrian Ogier, the editor of Positive Living, published by theNational Association of People with HIV Australia (NAPWHA).

Here, Adrian introduces the current issue of Positive Living.

A lot of people with HIV worry about losing our minds—particularly those of us who’ve had HIV for a while and are, how shall I put it, getting on in years…

We remember the toll paid before decent HIV treatments came along. Early in the epidemic about one in seven people with AIDS developed dementia, a diagnosis that usually progressed to severe disability and death within a year.

But there’s no need for panic. HIV-associated dementia is now so rare that the incidence is down to almost zero.

What we are seeing these days, however, is quite a bit of low-level neurocognitive impairment. Some of it is so low level, in fact, that while it can be picked up by a range of neuropsychological tests, the person with HIV and their significant others don’t even know anything is going on.

Up to 50 percent of people with HIV who are on treatment may be living with central nervous system abnormalities. Most of these are mild and include things like peripheral neuropathy, myopathy (limb muscle weakness, myalgia and muscle cramps) and changes in brain structure and functioning.

HIV gets into the central nervous system (CNS) quite early on – often within a week of infection. Over time it can cause an immune response, inflammation and the production of chemicals (cytokines and chemokines). All this may result in damage to a range of cells, particularly in the brain.

For some people on treatment, HIV still seems able to affect those parts of the brain related to cognitive ability, including memory, learning, attention and how fast we process things. The problem is that these losses are similar to those everyone experiences in older age. This intersection between ageing and HIV in the brain, together with a range of other factors, can make it difficult to untangle the relative contribution of each.

In the December issue of Positive Living, Neil McKellar-Stewart looks at HIV in the central nervous system and explains why taking treatment and a range of other health measures is so important for keeping our brains healthy. We also list some of the commonly-used HIV treatments in Australia and rate them according to their ability to penetrate the blood-brain barrier.

http://www.nurseuncut.com.au/positive-living-with-hiv/

What IS the Nervous System

Today's short post from sciencedaily.com (see link below) gives a relatively simple description of what the nervous system actually is. When people are told that they have neuropathy and that it involves damage to the nerves and an interruption to the normal working of the nervous system, they often just accept it and leave the consultation with a prescription. It's only when they get home that they wonder what the nervous system actually is and what's happened to it to cause such unpleasant symptoms. This article explains it technically but in terms that most won't have difficulty understanding. More detailed information can be found by following the link.

Nervous system

The nervous system of an animal coordinates the activity of the muscles, monitors the organs, constructs and also stops input from the senses, and initiates actions.

The nervous system of vertebrate animals is often divided into the central nervous system (CNS) and the peripheral nervous system (PNS).

The CNS consists of the brain and spinal cord.

The PNS consists of all other nerves and neurons that do not lie within the CNS.

The large majority of what are commonly called nerves (which are actually axonal processes of nerve cells) are considered to be PNS.

The peripheral nervous system is divided into the somatic nervous system and the autonomic nervous system.

The somatic nervous system is responsible for coordinating the body's movements, and also for receiving external stimuli.

It is the system that regulates activities that are under conscious control. The autonomic nervous system is then split into the sympathetic division, parasympathetic division, and enteric division.

The sympathetic nervous system responds to impending danger or stress, and is responsible for the increase of one's heartbeat and blood pressure, among other physiological changes, along with the sense of excitement one feels due to the increase of adrenaline in the system.

The parasympathetic nervous system, on the other hand, is evident when a person is resting and feels relaxed, and is responsible for such things as the constriction of the pupil, the slowing of the heart, the dilation of the blood vessels, and the stimulation of the digestive and genitourinary systems.

The role of the enteric nervous system is to manage every aspect of digestion, from the esophagus to the stomach, small intestine and colon.

http://www.sciencedaily.com/articles/n/nervous_system.htm

The Nervous System Explained In Video Form Vids

Today's two YouTube videos will definitely help you understand the nervous system that's short-circuiting and causing neuropathic problems in your body. The first video is an animated description of what the nervous system is and where it is in your body. The second video is presented by an enthusiastic young man and will give you all the information you may need about how your nervous system works. He's maybe not always as humorous as he thinks he is but he does present a staggering amount of information in a relatively short time. If you feel a little punch-drunk after watching it, you have to remember, nobody ever said that the nervous system was a simple structure...if it was, we wouldn't have so many problems understanding when it goes wrong and treating the symptoms that drive us mad in our daily lives. Worth a watch.

CNS and Nerve Conduction Animation - MADE EASY

 

https://www.youtube.com/watch?v=odZw2jvbjr8

This information is intended for educational purposes only, and should not be interpreted as medical advice. Please consult your physician for advice about changes that may affect your health.

The Nervous System - CrashCourse Biology #26



CrashCourse

 

 https://www.youtube.com/watch?v=x4PPZCLnVkA

 Published on 23 Jul 2012 Hank begins a series of videos on organ systems with a look at the nervous system and all of the things that it is responsible for in the body.  
Crash Course Biology is now available on DVD! http://dft.ba/-8bCC