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Nerves Work

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Last Updated: 02 July 2021

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General | Latest Info

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

Description of the nervous system

Nerves are cylindrical bundles of fibers that start at the brain and central cord and branch out to every other part of the body, according to University of Michigan Medical School. Neurons send signals to other cells through thin fibers called axons, which cause chemicals know as neurotransmitters to be released at junctions called synapses, NIH note. There are over 100 trillion neural connections in the average human brain, though number and location can vary. For example, new study published in January 2018 in the journal Proceedings of National Academy of Sciences found that out of 160 participants study, brains of highly creative people have more connections among three specific regions of the brain than less creative thinkers. You have these three different systems that are all located in different parts of the brain, but they are all co - activate at once, says lead study author Roger Beaty, postdoctoral fellow studying cognitive neuroscience at Harvard University. People who are better able to co - activate them with more - creative responses. The Synapse gives command to the cell and the entire communication process typically takes only a fraction of a millisecond. Signals travel along alpha motor neuron in the spinal cord 268 mph; fastest transmission in the human body, according to Discover magazine. Sensory neurons react to physical stimuli such as light, sound and touch and send feedback to the central Nervous System about the body's surrounding environment, according to the American Psychological Association. Motor neurons, located in the central Nervous System or in peripheral ganglia, transmit signals to activate muscles or glands. Glial cells, derive from the Greek word for glue, are specialized cells that support, protect or nourish nerve cells, according to Oregon Institute of Health and Science University. The brain's connections and thinking ability have grown over thousands of years of evolution. For example, virus bind its genetic code to the genome of four - limbed animals, and the code can still be found in human brains today, according to two papers published in the January 2018 journal Cell. This code packages up genetic information and sends it from nerve cells to other nearby nerve cells, very important process in the brain.


The Peripheral Nervous System (PNS)

The somatic nervous system keeps the body adept and coordinate, both through reflexes and voluntary action. Somatic nervous system control systems in areas as diverse as skin, bones, joints, and skeletal muscles. Afferent fibers, or nerves that receive information from external stimuli, carry sensory information through pathways that connect skin and skeletal muscles to CNS for processing. Information is then sent back via efferent nerves, or nerves that carry instructions from the CNS, back through the somatic system. These instructions go to neuromuscular junctionsthe interfaces between neurons and musclesfor motor output. Somatic systems also provide us with reflexes, which are automatic and do not require input or integration from the brain to perform. Reflexes can be categorized as either monosynaptic or polysynaptic based on reflex arc used to perform function. Monosynaptic reflex arcs, such as knee - jerk reflex, have only a single synapse between sensory neuron that receives information and motor neuron that respond. Polysynaptic reflex arcs, by contrast, have at least one interneuron between sensory neuron and motor neuron. An example of polysynaptic reflex arc is seen when a person steps on a tackin response, their body must pull that foot up while simultaneously transferring balance to other leg.


Neurons

The smallest worker in the nervous system is the neuron. For each of chain of impulses there is one preganglionic neuron, or one before cell body or ganglion, that is like central controlling body for numerous neurons going out peripherally. Preganglionic neurons are located in either the brain or spinal cord. In autonomic nervous system, this preganglionic neuron projects to autonomic ganglion. Postganglionic neurons were then projected to target organ. In the somatic nervous system, there is only one neuron between the central nervous system and the target organ while the autonomic nervous system uses two neurons.

* 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

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 nonprescription medicines, illegal drugs, or alcohol. Brain tumor. 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 behavior. 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

Many scientists and thinkers believe that the human nervous system is the most complex machine known to man. Its complexity points to one undeniable factthat it has evolved slowly over time from simpler forms. The evolution of the nervous system is intriguing not because we can marvel at this complicated biological structure, but it is fascinating because it inherits lineage of long history of many less complex nervous systems, and it documents record of adaptive behaviors observed in life forms other than humans. Thus, evolutionary study of the nervous system is important, and it is the first step in understanding its design, its workings, and its functional interface with the environment. The brains of some animals, like apes, monkeys, and rodents, are structurally similar to humans, while others are not. Do anatomical similarity of these brains suggest that behaviors that emerge in these species are also similar? Indeed, many animals display behaviors that are similar to humans,. Eg, apes use nonverbal communication signals with their hands and arms that resemble nonverbal forms of communication in humans. If we study very simple behaviors, like physiological responses made by individual neurons, then brain - base behaviors of invertebrates look very similar to humans, suggesting that from time immemorial such basic behaviors have been conserved in brains of many simple animal forms and, in fact, are the foundation of more complex behaviors in animals that evolve later. Even at micro - anatomical level, we note that individual neurons differ in complexity across animal species. Human neurons exhibit more intricate complexity than other animals; for example, neuronal processes in humans have many more branch points, branches, and spines. Complexity in the structure of the nervous system, both at macro - and micro - levels, gives rise to complex behaviors. We can observe similar movements of limbs, as in nonverbal communication, in apes and humans, but the variety and intricacy of nonverbal behaviors using hands in humans surpasses apes. Deaf individuals who use American Sign Language express themselves in English nonverbally; They use this language with such fine gradation that many accents of ASL exist. Complexity of behavior with increasing complexity of the nervous system, especially the cerebral cortex, can be observed in the genus Homo. If we compare the sophistication of material culture in Homo habilis and Homo sapiens, evidence shows that Homo habilis used crude stone tools compared with modern tools used by Homo sapiens to erect cities, develop write languages, embark on space travel, and study her own self. All of this is due to the increasing complexity of the nervous system. What has led to the complexity of the brain and nervous system through evolution, to its behavioral and cognitive refinement? Darwin proposes two forces of natural and sexual selection as work engines behind this change. He prophesy, psychology will be based on a new foundation, that of necessary acquirement of each mental power and capacity by gradation. That is, psychology will be based on evolution.

* 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?

The brain controls what you think and feel, how you learn and remember, and the way you move and talk. But it also controls things you are less aware of, like the beating of your heart and digestion of your food. Think of the brain as a central computer that controls all the body's functions. The rest of the nervous system is like a network that relays messages back and forth from the brain to different parts of the body. It does this via the spinal cord, which runs from the brain down through the back. It contains threadlike nerves that branch out to every organ and body part. When a message comes into the brain from anywhere in the body, brain tells the body how to react. For example, if you touch a hot stove, nerves in your skin shoot message of pain to your brain. The brain then sends a message back telling muscles in your hand to pull away. Luckily, this neurological relay race happened in an instant.


Brain and Nervous System

Considering everything it does, human brain is incredibly compact, weighing just 3 pounds. Its many folds and grooves, though, provide it with additional surface area necessary for storing all of bodys important information. The spinal cord, on the other hand, is a long bundle of nerve tissue about 18 inches long and inch thick. It extends from the lower part of the brain down through the spine. Along the way, various nerves branch out to the entire body. These make up the peripheral Nervous System. Both the brain and spinal cord are protected by bone: brain by bones of the skull, and the spinal cord by a set of ring - shape bones called vertebrae that make up the spine. They Theyre both cushioned by layers of membranes called meninges as well as special fluid called cerebrospinal fluid. This fluid helps protect nerve tissue, keep it healthy, and remove waste products. The brain is made up of three main sections: forebrain, midbrain, and hindbrain.

* 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

Overview

Nerve, in anatomy, glistening white cordlike bundle of fibres, surrounded by a sheath, that connects the nervous system with other parts of the body. Nerves conduct impulses toward or away from central nervous mechanism. In humans, 12 pairs, cranial nerves, are attached to the brain, and, as a rule, 31 pairs, spinal nerves, are attached to the spinal cord. Fibres constituting individual nerves are very numerous, and all, save those arising in sympathetic ganglia, extend from the brain or spinal cord to peripheral structures which they innervate. With respect to function, nerve fibres are divided into two categories, namely, sensory and motor. Fibres of these categories and their subdivisions constitute functional components of nerves. Combinations of such components vary in individual cranial nerves; in spinal nerves they are more uniform. Afferent fibres are divided into somatic and visceral groups. Somatic afferents conduct impulses received from outside the body or produced by movements of muscles and joints,. Those from muscles and joints are also known as proprioceptive fibres. Visceral afferents conduct messages from organs serving the internal economy of the body; such impulses result in reflex control of these organs. Motor fibres are divided into somatic and visceral motors or different groups. Somatic efferent fibres innervate voluntary muscles that derive from myotomes of embryo. Visceral motor fibres are divided into special visceral efferents, which innervate strip muscles of branchial origin, and general visceral efferents, which innervate involuntary muscles and secreting glands. General visceral efferent fibres constitute an autonomic system, of which there is sympathetic division and parasympathetic division, which differ from each other in anatomical arrangement and physiological characteristics. The term sympathetic is also frequently used to include both divisions as well as ganglia and afferent fibres associated with them. The Autonomic pathway involves a chain of two fibres, one arising in the brain or spinal cord and ending in a sympathetic ganglion, second arising in ganglion and passing to organ innervated. Cranial nerves are designated by name and also by number, Roman numerals being conventionally used as a rule. They emerge through openings of the skull. Some of cranial nerves are purely sensory, some entirely motor, and others mixed. Afferent fibres, save those of olfactory and optic nerves, arise in cranial sensory ganglia, situated in course of sensory nerves near the brain. Central processes terminate in sensory nuclei of the brain. Motor fibres arise within the brain from motor nuclei. In some instances, central nuclei, sensory or motor, are distinct from each nerve; in others, functional components of the same category from several nerves may arise from common nucleus. In addition to the 12 pairs of cranial nerves commonly describe, plexus, know as terminal nerve, is sometimes also recognized in humans, though whether it is vestigial structure or functioning nerve is unclear.

* 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 Anatomy

The majority of the nervous system is tissue made up of two classes of cells: neurons and neuroglia. Neurons, also known as nerve cells, communicate within the body by transmitting electrochemical signals. Neurons look quite different from other cells in the body due to many long cellular processes that extend from their central cell body. The cell body is roughly round part of the neuron that contains nucleus, mitochondria, and most of the cellular organelles. Small tree - like structures called dendrites extend from the cell body to pick up stimuli from the environment, other neurons, or sensory receptor cells. Long transmitting processes called axons extend from the cell body to send signals onward to other neurons or effector cells in the body. There are 3 basic classes of neurons: afferent neurons, Efferent neurons, and interneurons. Afferent neurons. Also known as sensory neurons, different neurons transmit sensory signals to the central nervous system from receptors in the body. Efferent neurons. Also known as motor neurons, Efferent neurons transmit signals from the central nervous system to effectors in the body such as muscles and glands. Interneurons. Interneurons form complex networks within the central nervous system to integrate information received from afferent neurons and to direct function of the body through different neurons. Neuroglia, also know as glial cells, act as ahelpera cells of the nervous system. Each neuron in the body is surrounded by anywhere from 6 to 60 neuroglia that protect, feed, and insulate neuron. Because neurons are extremely specialized cells that are essential to body function and almost never reproduce, neuroglia are vital to maintaining a functional 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

Nervous System Physiology

Each of 12 cranial nerves has a specific function within the nervous system. Olfactory nerves carry scent information to the brain from the olfactory epithelium on the roof of the nasal cavity. Optic nerves carry visual information from the eyes to the brain. Oculomotor, trochlear, and abducens nerves all work together to allow the brain to control movement and focus of the eyes. Trigeminal nerves carry sensations from face and innervate muscles of mastication. Facial nerves innervate muscles of the face to make facial expressions and carry taste information from the anterior 2 / 3 of the tongue. Vestibulocochlear nerve conduct auditory and balance information from ears to the brain. The Glossopharyngeal nerve carries taste information from posterior 1 / 3 of the tongue and assists in swallowing. Vagus nerve, sometimes called wandering nerve due to the fact that it innervate many different areas, awandersa through the head, neck, and torso. It carries information about the condition of vital organs to the brain, delivers motor signals to control speech and delivers parasympathetic signals to many organs. Accessory nerves control movements of the shoulders and neck. Hypoglossal nerve moves the tongue for speech and swallowing.


Functions of the Nervous System

The nervous system has 3 main functions: sensory, integration, and motor. Sensory. The sensory function of the nervous system involves collecting information from sensory receptors that monitor the bodyas internal and external conditions. These signals are then passed on to the central nervous system for further processing by afferent neurons. Integration. The process of integration is the processing of many sensory signals that are passed into CNS at any given time. These signals are evaluate, compare, used for decision making, discarded or committed to memory as deemed appropriate. Integration takes place in gray matter of the brain and spinal cord and is performed by interneurons. Many interneurons work together to form complex networks that provide this processing power. Motor. Once networks of interneurons in CNS evaluate sensory information and decide on action, they stimulate efferent neurons. Efferent neurons carry signals from gray matter of CNS through nerves of the peripheral nervous system to effector cells. Effector may be smooth, cardiac, or skeletal muscle tissue or glandular tissue. Effector then releases hormones or moves part of the body to respond to stimulus. Unfortunately, of course, our nervous system does always function as it should. Sometimes this is a result of diseases like Alzheimeras and Parkinsonas disease. Do you know that DNA testing can help you discover your genetic risk of acquiring certain health conditions that affect organs of our nervous system? Late - onset Alzheimeras, Parkinsonas disease, macular degeneration - visit our guide to DNA health testing to find out more.

* 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

Nerves in the body

Central nervous system: CNS is a body command center and is made up of your brain and the Spinal Cord. The brain is protected within your skull while your vertebrae protect your Spinal Cord. Peripheral nervous system: PNS is made up of nerves that branch off from your CNS. Nerves are bundles of axons that work together to transmit signals. PNS can be further broken up into sensory and motor divisions: sensory division transmits information from both inside and outside of your body to your CNS. This can include things like feelings of pain, smells, and sights. The motor division receives signals from CNS that cause action to occur. These actions can be voluntary, such as moving your arm, or involuntary like muscle contractions that help move food through your digestive tract.

* 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

Does length matter?

Our estimates are aggregated in the table below:

Connection typeTotal length (km)Average length per neuron (mm)Contributing neuron typesSources of evidence
Cerebral, short-range220,000 - 320,000 914 - 20Pyramidal (2/3rds to 85%), stellateFiber density in rats, morphometry
Cerebellar, short-range390,000 - 420,000 85.7 - 6.1Granule (~70%), stellate, basket, Purkinje, GolgiMorphometry
Total, short-range610,000 - 740,000---
Cerebral, long-range~50,000100PyramidalWidth of corpus callosum, relationship between brain volume and global connection length
Total, long-range150,000 - 180,000??Length density per white matter volume
Total, all fibers760,000 - 920,000---

* 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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