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3 Functions Of 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 systems regulate 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.

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Organization of the Nervous System

Key facts about the nervous system

DefinitionA network of neurons that sends, receives and modulates neural impulses between different body parts.
DivisionsCentral nervous system Peripheral nervous system
Central nervous systemBrain and spinal cord
Peripheral nervous systemSpinal and cranial nerves. Functional divisions: - Somatic nervous system - Autonomic nervous system; sympathetic, parasympathetic and enteric divisions

The nervous system is a network of neurons whose main feature is to generate, modulate and transmit information between all different parts of the human body. This property enables many important functions of the nervous system, such as regulation of vital body functions, sensation and body movements. Ultimately, nervous system structures preside over everything that makes us human; our consciousness, cognition, behaviour and memories. The central nervous system is the integration and command center of the body. The Peripheral nervous system represents conduit between CNS and body. It is further subdivided into somatic nervous system and autonomic nervous system. Understanding the nervous system requires knowledge of its various parts, so in this article you will learn about nervous system breakdown and all its various divisions.


Divisions of the Nervous System

Nervous System can be divided into two parts mostly on the basis of functional differences in responses. The Somatic Nervous System is responsible for conscious perception and voluntary motor responses. Voluntary motor response means contraction of skeletal muscle, but those contractions are not always voluntary in the sense that you have to want to perform them. Some somatic motor responses are reflexes, and often happen without conscious decision to perform them. If your friend jumps out from behind corner and yells " Boo! You will be startled and you might scream or leap back. You didnt decide to do that, and you may not have wanted to give your friend reason to laugh at your expense, but it is reflex involving skeletal muscle contractions. Other motor responses become automatic as people learn motor skills. The Autonomic Nervous System is responsible for involuntary control of the body, usually for the sake of homeostasis. Sensory input for autonomic functions can be from sensory structures tuned to external or internal environmental stimuli. Motor output extends to smooth and cardiac muscle as well as glandular tissue. The role of the autonomic system is to regulate organ systems of the body, which usually means to control homeostasis. Sweat glands, for example, are controlled by an autonomic system. When you are hot, sweating helps cool your body down. That is homeostatic mechanism. But when you are nervous, you might start sweating also. That is not homeostatic, it is a physiological response to emotional state. There is another division of Nervous System that describes functional responses. The Enteric Nervous System is responsible for controlling smooth muscle and glandular tissue in your digestive system. It is a large part of PNS, and is not dependent on CNS. It is sometimes valid, however, to consider the enteric system to be part of the autonomic system because neural structures that make up the enteric system are component of autonomic output that regulate digestion. There are some differences between the two, but for our purposes here there will be a good bit of overlap. See Figure 5 for examples of where these divisions of the Nervous System can be find.

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Functions of the Nervous System

The picture you have in your mind of the nervous system probably includes the brain, nervous tissue contained within the cranium, and spinal cord, extension of nervous tissue within the vertebral column. That suggests it is made of two organsand you may not even think of the spinal cord as an organbut, nervous system is a very complex structure. Within the brain, many different and separate regions are responsible for many different and separate functions. It is as if the nervous system is composed of many organs that all look similar and can only be differentiated using tools such as microscope or electrophysiology. In comparison, it is easy to see that the stomach is different than the esophagus or liver, so you can imagine the digestive system as a collection of specific organs.

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Chapter Review

The picture you have in your mind of the nervous system probably includes the brain, nervous tissue contained within the cranium, and spinal cord, extension of nervous tissue within the vertebral column. That suggests it is made of two organsand you may not even think of the spinal cord as an organbut, nervous system is a very complex structure. Within the brain, many different and separate regions are responsible for many different and separate functions. It is as if the nervous system is composed of many organs that all look similar and can only be differentiated using tools such as microscope or electrophysiology. In comparison, it is easy to see that the stomach is different than the esophagus or liver, so you can imagine the digestive system as a collection of specific organs. Nervous systems can be separated into divisions on the basis of anatomy and physiology. Anatomical divisions are central and peripheral nervous systems. Cns is brain and spinal cord. Pns is everything else. Functionally, nervous system can be divided into those regions that are responsible for sensation, those that are responsible for integration, and those that are responsible for generating responses. All of these functional areas are found in both central and peripheral anatomy. Considering anatomical regions of the nervous system, there are specific names for structures within each division. Localize collection of neuron cell bodies is referred to as nucleus in CNS and as ganglion in PNS. Bundle of axons is referred to as tract in CNS and as nerve in PNS. Whereas nuclei and ganglia are specifically in central or peripheral divisions, axons can cross boundary between two. A single axon can be part of a nerve and tract. Name for that specific structure depends on its location. Nervous tissue can also be described as gray matter and white matter on the basis of its appearance in unstained tissue. These descriptions are more often used in CNS. Gray matter is where nuclei are found and white matter is where tracts are find. In PNS, ganglia are basically gray matter and nerves are white matter. The nervous system can also be divided on the basis of how it controls the body. Somatic nervous system is responsible for functions that result in moving skeletal muscles. Any sensory or integrative functions that result in movement of skeletal muscle would be considered somatic. The autonomic nervous system is responsible for functions that affect cardiac or smooth muscle tissue, or that cause glands to produce their secretions. Autonomic functions are distributed between central and peripheral regions of the nervous system. Sensations that lead to autonomic functions can be the same sensations that are part of initiating somatic responses. Somatic and autonomic integrative functions may overlap as well. Special division of the nervous system is the enteric nervous system, which is responsible for controlling digestive organs.


The Central and Peripheral Nervous Systems

The brain is the most complex and sensitive organ in the body. It is responsible for all functions of the body, including serving as a coordinating center for all sensations, mobility, emotions, and intellect. Protection for the brain is provided by the bones of the skull, which in turn are covered by scalp, as shown in Figure 2. A scalp is composed of an outer layer of skin, which is loosely attached to aponeurosis, flat, broad tendon layer that anchors superficial layers of skin. Periosteum, below aponeurosis, firmly encase bones of the skull and provide protection, nutrition for bone, and capacity for bone repair. Below the skull are three layers of membranes called meninges that surround the brain. Relative positions of these meninges are shown in Figure 2. The meningeal layer closest to the bones of the skull is called dura mater. Below dura mater lie arachnoid mater. The innermost meningeal layer is a delicate membrane called pia mater. Unlike other meningeal layers, pia mater firmly adheres to the convoluted surface of the brain. Between arachnoid mater and pia mater is subarachnoid space. Subarachnoid space is filled with cerebrospinal fluid, which is produced by cells of choroid plexusareas in each ventricle of the brain that consist of cuboidal epithelial cells surrounding dense capillary beds. Csf serves to deliver nutrients and remove waste from neural tissues.

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Review Questions

Action potential travels along the axon until it depolarizes membrane at the axon terminal. Depolarization of the membrane causes voltage - gate Ca 2 + channels to open and Ca 2 + to enter the cell. Intracellular calcium influx causes synaptic vesicles containing neurotransmitter to fuse with presynaptic membrane. The neurotransmitter diffuses across synaptic cleft and binds to receptors on the postsynaptic membrane. Depending on specific neurotransmitter and postsynaptic receptor, this action can cause positive or negative ions to enter the cell. The sympathetic nervous system prepares the body for fight or flight, whereas the parasympathetic nervous system allows the body to rest and digest. Sympathetic neurons release norepinephrine onto target organs; parasympathetic neurons release acetylcholine. Sympathetic neuron cell bodies are located in sympathetic ganglia. Parasympathetic neuron cell bodies are located in the brainstem and sacral spinal cord. Activation of the sympathetic nervous system increases heart rate and blood pressure and decreases digestion and blood flow to skin. Activation of the parasympathetic nervous system decreases heart rate and blood pressure and increases digestion and blood flow to 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

Description of the nervous system

Nervous systems can also be divided on the basis of their functions, but anatomical divisions and functional divisions are different. Cns and PNS both contribute to the same functions, but those functions can be attributed to different regions of the brain or to different ganglia in the periphery. The problem with trying to fit functional differences into anatomical divisions is that sometimes the same structure can be part of several functions. For example, optic nerve carries signals from the retina that are either used for conscious perception of visual stimuli, which take place in the cerebral cortex, or for reflexive responses of smooth muscle tissue that are processed through the hypothalamus. There are two ways to consider how the nervous system is divided functionally. First, basic functions of the nervous system are sensation, integration, and response. Secondly, control of the body can be somatic or autonomicdivisions that are largely defined by structures that are involved in response. There is also a region of the peripheral nervous system that is called the enteric nervous system that is responsible for a specific set of functions within the realm of autonomic control relating to gastrointestinal functions. The nervous system is involved in receiving information about the environment around us and generating responses to that information. Nervous systems can be divided into regions that are responsible for sensation and for response. But there is a third function that needs to be include. Sensory input needs to be integrated with other sensations, as well as with memories, emotional state, or learning. Some regions of the nervous system are term integration or Association areas. The process of integration combines sensory perceptions and higher cognitive functions such as memories, learning, and emotion to produce a response. The first major function of the nervous system is sensationreceiving, information about the environment to gain input about what is happening outside the body. Sensory functions of the nervous system register the presence of change from homeostasis or particular event in the environment, know as stimulus. Sense we think of most are the big five: taste, smell, touch, sight, and hearing. Stimuli for taste and smell are both chemical substances, touch is physical or mechanical stimuli that interact with skin, sight is light stimuli, and hearing is perception of sound, which is a physical stimulus similar to some aspects of touch. There are actually more senses than just those, but that list represents major senses. Those five are all senses that receive stimuli from the outside world, and of which there is conscious perception. Additional sensory stimuli might be from the internal environment, such as stretching of the organ wall or concentration of certain ions in blood. The nervous system produces response on the basis of stimuli perceived by sensory structures.

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* 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.


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.

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* 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

A number of different medical conditions can affect the nervous system, including: blood vessel disorders in the brain, including arteriovenous malformations and cerebral aneurysms Tumors, benign and malignant degenerative diseases, including Alzheimer's disease and Parkinson's disease. Disorders of pituitary gland Epilepsy Headaches, including migraines head injuries such as concussions and brain trauma Movement Disorders, such as tremors and Parkinson disease Demyelinating diseases such as Multiple sclerosis Neuro - ophthalmologic diseases, which are vision problems that result from damage to optic Nerve or its connections to brain Peripheral Nerve diseases, which affect nerves that carry information to and from brain and Spinal cord Mental Disorders, such as schizophrenia Spine Disorders Infections, such as meningitis Stroke neurologists and other neuroscience specialists use special tests and imaging techniques to see how nerves and brain are working. In addition to blood and urine tests, tests to diagnose nervous system diseases may include: compute tomography lumbar puncture to check for infection of spinal cord and brain, or to measure pressure of cerebro - Spinal fluid magnetic resonance imaging or magnetic resonance angiography electroencephalography to look at brain activity Electromyography to test Nerve and muscle function Electronystagmography to check for abnormal eye movements, which can be sign of brain disorder evoke potentials, which look at how brain respond to sounds, sight, and touch Magnetoencephalography myelogram of Spine to diagnose Nerve injury Nerve conduction velocity test Neurocognitive testing polysomnogram to see how brain react during sleep Single photon emission compute tomography and positron emission tomography scan to look at brain metabolic activity Biopsy of brain, Nerve, skin, or muscle to determine if there's problem with nervous system neuroradiology is branch of neuroscience medicine that focus on diagnosing and treating nervous system problems. Interventional neuroradiology involves inserting tiny, flexible tubes called catheters into blood vessels leading to the brain. This allows doctors to treat blood vessel disorders that can affect the nervous system, such as stroke. Balloon angioplasty and stenting of carotid or vertebral artery Endovascular embolization and coiling to treat cerebral aneurysms Intra - arterial therapy for Stroke Radiation oncology of brain and Spine Needle biopsies, Spine and soft tissues Kyphoplasty and vertebroplasty to treat vertebral fractures open or traditional neurosurgery may be needed in some cases to treat problems in brain and surrounding structures. This is more invasive surgery that requires surgeon to make an opening, called craniotomy, in the skull. Microsurgery allows surgeons to work on very small structures in the brain using microscope and very small, precise instruments. Stereotactic radiosurgery may be needed for certain types of nervous system disorders. This is a form of radiation therapy that focuses high - power x - rays on small areas of the body, thereby avoiding damage to surrounding brain tissue.


Overview of Nervous System Disorders

Healthcare providers who treat nervous system disorders may have to spend a lot of time working with patients before making a probable diagnosis of a specific condition. Many times, this involves performing numerous tests to eliminate other conditions, so that probable diagnosis can be make. Neurology. The branch of medicine that manages nervous system disorders is called neurology. Medical healthcare providers who treat nervous system disorders are called neurologists. Some neurologists treat acute strokes and cerebral aneurysms using endovascular techniques. Neurological surgery. The branch of medicine that provides surgical intervention for nervous system disorders is called neurosurgery, or neurological surgery. Surgeons who operate as treatment teams for nervous system disorders are called neurological surgeons or neurosurgeons. Neuroradiologists and interventional radiologists. Radiologists specialize in diagnosis of neurological conditions using imaging and in treatment of certain neurologic conditions such as cerebral aneurysms, acute strokes, and vertebral fractures, as well as biopsies of certain tumors. Rehabilitation for neurological disorders. The branch of medicine that provides rehabilitative care for patients with nervous system disorders is called physical medicine and rehabilitation. Healthcare providers who work with patients in the rehabilitation process are called physiatrists.

* 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

The branch of medicine that studies and treats the nervous system is called Neurology, and doctors who practice in this field of medicine are called neurologists. Once they have completed medical training, neurologists complete additional training for their specialty and are certified by the American Board of Psychiatry and Neurology. There are also physiatrists, who are physicians who work to rehabilitate patients who have experienced disease or injury to their nervous systems that impact their ability to function, according to ABPN. Neurosurgeons perform surgeries involving the nervous system and are certified by the American Association of Neurological Surgeons. You use your eyes to see, your ears to hear and your muscles to do heavy lifting. Well, sort of. In fact, most body parts are far more complicated than that, while some seem to have no business being inside there at all.

* 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 vs. 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.

* 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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