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The Function Of The Nervous System

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Last Updated: 02 July 2021

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The nervous system is a complex collection of nerves and specialized cells know as neurons that transmit signals between different parts of the body. It is essentially the body's electrical wiring. Structurally, nervous system has two components: central nervous system and the peripheral nervous system. According to the National Institutes of Health, central nervous system is made up of the brain, spinal cord and nerves. The peripheral nervous system consists of sensory neurons, ganglia and nerves that connect to one another and to the central nervous system. Functionally, nervous system has two main subdivisions: somatic, or voluntary, component; and autonomic, or involuntary, component. The Autonomic nervous system regulates certain body process, such as blood pressure and rate of breathing, that work without conscious effort, according to Merck Manuals. The somatic system consists of nerves that connect the brain and spinal cord with muscles and sensory receptors in the skin.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Diagnosing nervous system conditions

There are a number of tests and procedures to diagnose conditions involving the nervous system. In addition to traditional X - ray, specialized X - ray called fluoroscopy examines the body in motion, such as blood flowing through arteries, according to NIH. Other standard neurological exams include MRI, CT scan, and electroencephalogram, which record the brain's continuous electrical activity. Positron emission tomography is a procedure that measures cell or tissue metabolism and brain activity to detect tumors or diseased tissue or tumors, NIH note. The Spinal tap places a needle into the spinal canal to drain a small amount of cerebral spinal fluid that is tested for infection or other abnormalities, according to NIH.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Diseases of the nervous system

Of all diseases of the nervous system, most common difficulty that people have is pain, and much of that is nerve - relate, according to Dr. Shai Gozani, founder and CEO of NeuroMetrix, medical device company. There are 100 million people who live with chronic pain. According to Mayo Clinic, patients with Nerve Disorders experience functional difficulties, which result in conditions such as: Epilepsy, in which abnormal electrical discharges from brain cells cause seizures, Parkinson's disease, which is a progressive nerve disease that affects Movement Multiple sclerosis, in which protective lining of nerves is attacked by the body's immune system Amyotrophic lateral sclerosis, also know as Lou Gehrig's disease, is motor neuron disease which weaken muscles and progressively hampers Physical function Huntington's disease, which is inherit condition that cause Nerve cells in brain to degenerate Alzheimer's disease, which cover wide range of Disorders that impact Mental functions, particularly memory. Mayo Clinic also notes that the nervous system can also be affected by Vascular Disorders such as: Stroke, which occur when there is bleeding in the brain or blow flow to the brain is obstruct; Transient ischemic attack, which are mini - type strokes that last a shorter period of time but mimic Stroke symptoms; and Subarachnoid hemorrhage, which is specifically bleeding in space between your brain and surrounding membrane that can be result of trauma or rupturing of weak blood vessel; Infections such as meningitis, encephalitis, polio, and epidural abscess can also affect nervous system, NIH note. Treatments vary from anti - inflammatory medications and pain medications such as opiates, to implanted nerve stimulators and wearable devices, Gozani say. Many people also turn to herbal and holistic methods to reduce pain, such as acupuncture.


Overview of Nervous System Disorders

The Nervous system is a complex, highly specialized network. It organize, explains, and directs interactions between you and the world around you. The nervous system controls: sight, hearing, taste, smell, and feeling. Voluntary and involuntary functions, such as movement, balance, and coordination. Nervous systems also regulate actions of most other body systems, such as blood flow and blood pressure. Ability to think and reason. The nervous system allows you to be conscious and have thoughts, memories, and language. The nervous system is divided into brain and spinal cord and nerve cells that control voluntary and involuntary movements. Symptoms of nervous system problem depend on which area of the nervous system is involved and what is causing the problem. Nervous system problems may occur slowly and cause gradual loss of function. Or they may occur suddenly and cause life - threatening problems. Symptoms may be mild or severe. Some serious conditions, diseases, and injuries that can cause nervous system problems include: blood supply problems. Injuries, especially injuries to the head and spinal cord. Problems that are present at birth. Mental health problems, such as anxiety disorders, depression, or psychosis. Exposure to toxins, such as carbon monoxide, arsenic, or lead. Problems that cause gradual loss of function. Examples include: Parkinson's disease. Multiple sclerosis. Amyotrophic lateral sclerosis. Alzheimer's disease. Huntington's disease. Peripheral neuropathies. Infections. These may occur in: brain. The Membrane surrounds the brain and spinal cord. Overuse of or withdrawal from prescription and non - prescription medicines, illegal drugs, or alcohol. Brain tumour. Organ system failure. Examples include: Respiratory failure. Heart failure. Liver failure. Kidney failure. Other conditions. Some examples include: Thyroid dysfunction. High blood sugar or low blood sugar. Electrolyte problems. Nutritional deficiencies, such as vitamin B1 or vitamin B12 deficiency. Guillain - Barre syndrome. Sudden nervous system problems can cause many different symptoms, depending on the area of nervous system involve. Strokes and transient ischemic attacks are common examples of acute problems. You may experience sudden onset of one or more symptoms, such as: numbness, tingling, weakness, or inability to move part or all of one side of your body. Dimness, blurring, double vision, or loss of vision in one or both eyes. Loss of speech, trouble talking, or trouble understanding speech. Sudden, severe headache. Dizziness, unsteadiness, or inability to stand or walk, especially if other symptoms are present. Confusion or change in level of consciousness or behaviour. Severe nausea or vomiting. Seizures can also cause sudden changes in consciousness, feeling,s emotion,s or thought.S Abnormal body movements, such as muscle twitching, may or may not be present. How often seizures occur and how severe they are depends on the cause of seizures and the area of the brain involve. For more information, see topic Seizures. Diabetes can cause problems with balance, either as a result of peripheral neuropathy or stroke. Vertigo and Dizziness are problems of balance and coordination.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Study of the nervous system

Studying the nervous system involves anatomical and physiological techniques that have improved over years in efficiency and caliber. Clearly, gross morphology of the nervous system requires an eye - level view of the brain and spinal cord. However, to resolve minute components, optical and electron microscopic techniques are needed Light microscopes and, later, electron microscopes have changed our understanding of intricate connections that exist among nerve cells. For example, modern staining procedures make it possible to see selected neurons that are of one type or another or are affected by growth. With better resolution of electron microscopes, fine structures like synaptic cleft between pre - and post - synaptic neurons can be studied in detail. Along with neuroanatomical techniques, number of other methodologies aid neuroscientists in studying function and physiology of the nervous system. Early on, lesion studies in animals provide information about the function of the nervous system, by ablating parts of the nervous system or using neurotoxins to destroy them and documenting effects on behavior or mental processes. Later, more sophisticated microelectrode techniques were introduce, which led to recording of single neurons in animal brains and investigating their physiological functions. Such studies lead to formulating theories about how sensory and motor information are processed in the brain. To study many neurons, electroencephalographic techniques were introduce. These methods are used to study how large ensembles of neurons, representing different parts of the nervous system, with or without stimulation, function together. In addition, many scanning techniques that visualize the brain in conjunction with methods mentioned above are used to understand details of the structure and function of the brain. These include computerized axial Tomography, which uses X - rays to capture many pictures of the brain and sandwiches them into 3 - D models to study it. The resolution of this method is inferior to magnetic resonance imaging, which is yet another way to capture brain images using large magnets that bobble hydrogen nuclei in the brain. Although the resolution of MRI scans is much better than CAT scans, they do not provide any functional information about the brain. Positron Emission Tomography involves acquisition of physiologic images of the brain based on detection of positrons. Radio - labeled isotopes of certain chemicals, such as analogs of glucose, enter Active nerve cells and emit positrons, which are captured and mapped into scans. Such scans show how the brain and its many modules become active when energized with entering glucose analog. Disadvantages of PET scans include being invasive and rendering poor spatial resolution. The latter is why modern PET machines are coupled with CAT scanners to gain better resolution of functioning brain. Finally, to avoid the invasiveness of PET, functional MRI techniques were develop. Brain images based on fMRI technique visualize brain function by changes in flow of fluids in brain areas that occur over time.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

What Does the Brain Do?

As a species, humans have evolved a complex nervous system and brain over millions of years. Comparisons of our nervous systems with those of other animals, such as chimpanzees, show some similarities. Researchers can also use fossils to study the relationship between brain volume and human behavior over the course of evolutionary history. Homo habilis, for instance, human ancestor living about 2 million years ago show larger brain volume than its own ancestors but far less than modern homo sapiens. The main difference between humans and other animals - in terms of brain development - is that humans have a much more developed frontal cortex. Interestingly, people's unique nervous systems develop over the course of their lifespan in a way that resembles the evolution of nervous systems in animals across vast stretches of time. For example, human nervous system begins developing even before a person is born. It begins as a simple bundle of tissue that forms into a tube and extends along head - to - tail plane becoming spinal cord and brain. 25 days into its development, embryo has distinct spinal cord, as well as hindbrain, midbrain and forebrain. What, exactly, is this nervous system developing and what does it do? The nervous system can be thought of as the body's communication network that consists of all nerve cells. There are many ways in which we can divide the nervous system to understand it more clearly. One common way to do so is by parsing it into the central nervous system and peripheral nervous system. Each of these can be sub - divide, in turn. Lets take a closer, more in - depth look at each. And, dont worry, nervous system is complicated with many parts and many new vocabulary words. It might seem overwhelming at first, but through figures and little study you can get it.


Brain and Nervous System

The Central Nervous System, or CNS for short, is made up of the brain and spinal cord. Cns is a portion of the nervous system that is encase in bone. It is referred to as Central because it is the brain and spinal cord that are primarily responsible for processing sensory informationtouching hot stove or seeing rainbow, for exampleand, sending signals to the peripheral Nervous System for action. It communicates largely by sending electrical signals through individual nerve cells that make up fundamental building blocks of the Nervous System, called neurons. There are approximately 100 billion neurons in the human brain and each has many contacts with other neurons, called synapses. If we were able to magnify the view of individual neurons, we would see that they are cells made from distinct parts. Three main components of neuron are dendrites, soma, and axon. Neurons communicate with one another by receiving information through dendrites, which act as antenna. When dendrites channel this information to the soma, or cell body, it builds up as an electro - chemical signal. This electrical part of the signal, called action potential, shoots down axon, long tail that leads away from soma and toward the next neuron. When people talk about nerves in the Nervous System, it typically refers to bundles of axons that form long neural wires along which electrical signals can travel. Cell - to - cell communication is helped by the fact that the axon is covered by a myelin sheath layer of fatty cells that allow signals to travel very rapidly from neuron to neuron. If we were to zoom in still further, we could take a closer look at synapse, space between neurons. Here, we would see that there is space between neurons, called the synaptic gap. To give you a sense of scale, we can compare the synaptic gap to the thickness of the dime, thinnest of all American coins. You could stack approximately 70 000 synaptic gaps in the thickness of a single coin! As action potential, electrical signal reaches the end of the axon, tiny packets of chemicals, called neurotransmitters, are release. This is chemical part of electro - chemical signal. These neurotransmitters are chemical signals that travel from one neuron to another, enabling them to communicate with one another. There are many different types of neurotransmitters and each has a specialized function. For example, serotonin affects sleep, hunger and mood. Dopamine is associated with attention, learning and pleasure. It is amazing to realize that when you thinkwhen you reach out to grab a glass of water, when you realize that your best friend is happy, when you try to remember the names of parts of the neuronwhat you are experiencing is actually electro - chemical impulses shooting between nerves!

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Nervous System Function

The primary function of the nervous system is to receive information and to generate response to give stimulus. Information and response could be simple, subtle or complex. For instance, when a hot object is touch, its temperature is conveyed quickly to the central nervous system and the response is immediate reflex of removing hand, through action of skeletal muscles. A few such incidents could also lead to formation of learning and long - term memory encoded as a series of neural connections. Alternatively, it could be the sensation of a cold drink on a hot day, where the body responds with a feeling of pleasure. This is expressed through neuronal activity in various parts of the body, depending on the individual, not relying on any obvious effector cell. On other end of the spectrum, stimulus could be indirect, such as the sound of rustling leaves in quiet forest, indicative of animals slithering. This could lead to a cascade of responses. The body might respond to this sound with an adrenalin rush, prompting flight response, and changing the metabolic state of skeletal, smooth and cardiac muscles. It could also retrieve memory and try to recollect the possibility of animal being a venomous snake, and the best possible route for escape. Much of this happens nearly instantaneously. Some parts of the nervous system can encode information from stimuli so intricately and deeply, that victims of traumatic events relive painful moments in their entirety, with a whole host of physiological responses, even with unrelated stimulus.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Cells of the nervous system

Major Neurotransmitters and How They Affect Behavior

NeurotransmitterInvolved inPotential Effect on Behavior
AcetylcholineMuscle action, memoryIncreased arousal, enhanced cognition
Beta-endorphinPain, pleasureDecreased anxiety, decreased tension
DopamineMood, sleep, learningIncreased pleasure, suppressed appetite
Gamma-aminobutyric acid (GABA)Brain function, sleepDecreased anxiety, decreased tension
GlutamateMemory, learningIncreased learning, enhanced memory
NorepinephrineHeart, intestines, alertnessIncreased arousal, suppressed appetite
SerotoninMood, sleepModulated mood, suppressed appetite

Neurons connect with one another to send and receive messages in the brain and spinal cord. Many neurons working together are responsible for every decision make, every emotion or sensation felt, and every action take. The complexity of the central nervous system is amazing: there are approximately 100 billion neurons in the brain and spinal cord combine. As many as 10 000 different subtypes of neurons have been identify, each specializing in sending and receiving certain types of information. Each neuron is made up of a cell body, which houses nucleus. Axons and dendrites form extensions from the cell body. Astrocytes, kind of glial cell, are primary support cells of the brain and spinal cord. They make and secrete proteins called neurotrophic factors. They also break down and remove proteins or chemicals that might be harmful to neurons. Astrocytes aren't always beneficial: after injury, they divide to make new cells that surround the injury site, forming a glial scar that is a barrier to regenerating axons. Microglia are immune cells for the brain. After injury, they migrate to the site of injury to help clear away dead and dying cells. They can also produce small molecules called cytokines that trigger cells of the immune system to respond to injury site. This clean - up process is likely to play an important role in recovery of function following spinal injury.


Neurons

Neurons, or nerve cell, are the main structural and functional units of the nervous system. Every neuron consists of the body and a number of processes. The nerve cell body contains cellular organelles and is where neural impulses are generate. Processes stem from the body, They connect neurons with each other and with other body cells, enabling the flow of neural impulses. There are two types of neural processes that differ in structure and function; axons are long and conduct impulses away from the neuronal body. Dendrites are short and act to receive impulses from other neurons, conducting electrical signal towards the nerve cell body. Every neuron has a single axon, while the number of dendrites varies. Base on that number, there are four structural types of neurons; multipolar, bipolar, pseudounipolar and unipolar.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Somatic nervous system

After Timmy was all patched up, his mother made him a grilled cheese sandwich, which was his favorite. Within five minutes, whole sandwich was in Timmy's stomach. Sensory neurons in the stomach wall are stimulated by the presence of food and send signals to the brain. The brain then relays signal back to motor neurons in the stomach that stimulate secretion of gastric juice, and contractions of stomach muscles to mix food and gastric juice. This nervous pathway is one example of a function controlled by the autonomic nervous system, which is part of the nervous system that involuntarily regulates internal body functions. Other body functions that are also under autonomic control are breathing, heart rate, salivation, pupil dilation, sweating, and blood vessel constriction and dilation, to name a few. In contrast, somatic nervous system is part of the nervous system that voluntarily responds to external stimuli. All of the different senses that Timmy experienced earlier in the lesson, like sight, hearing, pain and cold, and his conscious mental and physical responses to them, are all parts of the somatic nervous system. In many cases, both of these systems work together in a coordinated fashion. When Timmy heard neighbor's dog bark and get scar, his heart rate and breathing rate were immediately increased by his autonomic nervous system so that he could run away, action controlled by somatic nervous system.


The Central and Peripheral Nervous Systems

Nerves in PNS transmit information from all parts of the body to and from the CNS. In total, there are 43 pairs of nerves in PNS12, cranial nerves and 31 spinal nerves. Nerves of PNS can be either myelinated or unmyelinated in nature. Whether they have this myelin or not, they do have the same general feature in that nerves contain nerve fibers with axons of either afferent or efferent neurons. Therefore, nerves of PNS can be classified as belonging to either afferent or efferent. With spinal nerves, they contain both afferent and efferent information, whereas some cranial nerves like olfactory and optic nerves contain only afferent information. Afferent information transmits impulses from receptors to the CNS. Their axons are found outwith CNS, but then enter CNS. Efferent information, however, transmits information from CNS externally to, for example, glands and muscles. It is worth noting that different divisions are subclassified into what they ultimately supply. Further classification use of efferent division is somatic and autonomic nervous system. Simply put, somatic nervous system innervates skeletal muscle, whereas ANS innervates glands, neurons of gastrointestinal tract, and cardiac and smooth muscles of glandular tissue.


Introduction to the Nervous System

There are two nervous systems in mammals. One is a somatic nervous system and the other is an autonomic nervous system. The role of somatic nerves is to control the external environment by somatosensory function and motor function. 1 When animals or humans feel cold, they can move to warm place to survive. The role of the autonomic nervous system is to control the internal environment or milieu interieur, named by Claude Bernard. 1 Controlling the internal environment is called homeostasis and was initially conceptualized by American physiologist Walter B. Cannon. 2 Like somatic nerves, autonomic nervous system also has viscerosensory function and visceromotor function. The autonomic nervous system is visceral and largely involuntary sensory and motor system. Modulation of the internal environment by autonomic nervous system is more complex because it has intrinsic and extrinsic activities. Moreover, homeostasis is also regulated by the endocrine system. 1 When the gut is distended by consuming foods, viscerosensory neurons excite and visceromotor responses occur and summon peristalsis, intestino - intestinal inhibitory reflex, and centrally mediate extrinsic activities. 3 These activities are mainly regulated by the hypothalamus and other brain regions. Hans H. Selye proposed the concept of stress via gastric ulcer, thymic atrophy, and adrenocortical hypertrophy under aversive stimuli for mammals. 4 Among these changes in stress, adrenocortical hypertrophy is a representative phenomenon of activation of hypothalamic - pituitary - adrenal axis. The Hypothalamus, in turn, acts on three major systems: autonomic nervous system, endocrine system, and neural system concerned with motivation. 1 This chapter highlights the role of the hypothalamus, mainly on HPA axis and gastrointestinal function.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Autonomic nervous system

Patients should take take - blockers on the day of surgery and continue them period Because receptors are up - regulate, withdrawal may precipitate hypertension, Tachycardia, and myocardial ischemia. 2. Clonidine should also be continued period because of concerns about rebound hypertension. 3. Indirect - acting sympthomimetics depend on norepinephrine release to be effective. Norepinephrine - deplete states will not respond to ephedrine administration. 4. Under most circumstances, peri - induction Hypotension responds best to intravenous fluid administration and use of direct - acting sympathomimetics such as phenylephrine. 5. Orthostatic Hypotension is common after surgery and may be caused by use of any or all anesthetic agents and lying supine for extended periods. It is necessary to be cognizant of this potential problem when elevating a patient's head after surgery or even when moving a patient from operating room table to chair. Autonomic nervous system abnormalities are common in SS and may play an etiologic role in its pathogenesis. Xerostomia and xerophthalmia, cardinal SS manifestations, are features of cholinergic parasympathetic ANS dysfunction, whereas sympathetic cholinergic failure results in xerosis and decreased sweating, which are frequently reported by SS patients. The Complexity of ANS along with differences in methodology and studied populations has resulted in variable results, but abnormalities in SS have been reported in both sympathetic and parasympathetic ANS domains. Delay gastric emptying is common in SS and is consistent with involvement of enteric ANS. The underlying cause of these ANS abnormalities has not yet been defined but they may potentially be mediated through interference with muscarinic receptor signaling. Recently, it was shown that IgG from SS patients blocks acetlylcholine - mediate contraction of smooth muscle preparations from various parts of the Gastrointestinal tract and that this effect was specific to interference with muscarinic acetylcholine receptor - 3. 12 Although other mechanisms cannot be exclude, anti - muscarinic acetylcholine receptor autoantibodies would provide a link between autoimmunity and ANS dysfunction in SS.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Sources

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

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