Nerves in the context of "Parazoa"

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⭐ Core Definition: Nerves

A nerve is an enclosed, cable-like bundle of nerve fibers (called axons). Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the electrochemical nerve impulses called action potentials that are transmitted along each of the axons to peripheral organs or, in the case of sensory nerves, from the periphery back to the central nervous system. Each axon is an extension of an individual neuron, along with other supportive cells such as some Schwann cells that coat the axons in myelin.

Each axon is surrounded by a layer of connective tissue called the endoneurium. The axons are bundled together into groups called fascicles, and each fascicle is wrapped in a layer of connective tissue called the perineurium. The entire nerve is wrapped in a layer of connective tissue called the epineurium. Nerve cells (often called neurons) are further classified as either sensory or motor.

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👉 Nerves in the context of Parazoa

Parazoa (Parazoa, gr. Παρα-, para, "next to", and ζωα, zoa, "animals") is an obsolete subkingdom that is located at the base of the phylogenetic tree of the animal kingdom in opposition to the subkingdom Eumetazoa; they group together the most primitive forms, characterized by not having proper tissues or where, in any case, these tissues are only partially differentiated. It generally includes a single phylum, Porifera, which lack muscles, nerves and internal organs, which in many cases resembles a cell colony rather than a multicellular organism itself. All other animals are eumetazoans and agnotozoans (Agnotozoans are possibly paraphyletic or even nonexistent in studies), which do have differentiated tissues.

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Nerves in the context of Stimulation

Stimulation is the encouragement of development or the cause of activity in general. For example, "The press provides stimulation of political discourse." An interesting or fun activity can be described as "stimulating", regardless of its physical effects on senses. Stimulate means to act as a stimulus to; stimulus means something that rouses the recipient to activity; stimuli is the plural of stimulus.

A particular use of the term is physiological stimulation, which refers to sensory excitation, the action of various agents or forms of energy (stimuli) on receptors that generate impulses that travel through nerves to the brain (afferents). There are sensory receptors on or near the surface of the body, such as photoreceptors in the retina of the eye, hair cells in the cochlea of the ear, touch receptors in the skin and chemical receptors in the mouth and nasal cavity. There are also sensory receptors in the muscles, joints, digestive tract, and membranes around organs such as the brain, the abdominal cavity, the bladder and the prostate (providing one source of sexual stimulation). Stimulation to the external or internal senses may evoke involuntary activity or guide intentions in action. Such emotional or motivating stimulation typically is also experienced subjectively (enters awareness, is in consciousness). Perception can be regarded as conceptualised stimulation, used in reasoning and intending, for example. When bodily stimulation is perceived it is traditionally called a sensation, such as a kind of touch or a taste or smell, or a painful or pleasurable sensation. This can be thought of as psychological stimulation, which is a stimulus affecting a person's thinking or feeling processes.

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Nerves in the context of Calcium supplementation

Calcium supplements are salts of calcium used in a number of conditions. Supplementation is generally only required when there is not enough calcium in the diet. By mouth they are used to treat and prevent low blood calcium, osteoporosis, and rickets. By injection into a vein they are used for low blood calcium that is resulting in muscle spasms and for high blood potassium or magnesium toxicity.

Common side effects include constipation and nausea. When taken by mouth high blood calcium is uncommon. Calcium supplements, unlike calcium from dietary sources, appear to increase the risk of kidney stones. Adults generally require about a gram of calcium a day. Calcium is particularly important for bones, muscles, and nerves.

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Nerves in the context of Neurological disorder

A neurological disorder is any disorder of the nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord, or other nerves can result in a range of symptoms. Examples of symptoms include paralysis, muscle weakness, poor coordination, loss of sensation, seizures, confusion, pain, tauopathies, and altered levels of consciousness. There are many recognized neurological disorders; some are relatively common, but many are rare.

Interventions for neurological disorders include preventive measures, lifestyle changes, physiotherapy or other therapy, neurorehabilitation, pain management, medication, operations performed by neurosurgeons, or a specific diet. The World Health Organization estimated in 2006 that neurological disorders and their sequelae (direct consequences) affect as many as one billion people worldwide and identified health inequalities and social stigma/discrimination as major factors contributing to the associated disability and their impact.

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Nerves in the context of Aponeuroses

An aponeurosis (/ˌæpənjʊəˈrsɪs/; pl.: aponeuroses) is a flattened tendon by which muscle attaches to bone or fascia. Aponeuroses exhibit an ordered arrangement of collagen fibres, thus attaining high tensile strength in a particular direction while being vulnerable to tensional or shear forces in other directions. They have a shiny, whitish-silvery color, are histologically similar to tendons, and are very sparingly supplied with blood vessels and nerves. When dissected, aponeuroses are papery and peel off by sections. The primary regions with thick aponeuroses are in the ventral abdominal region, the dorsal lumbar region, the ventriculus in birds, and the palmar (palms) and plantar (soles) regions.

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Nerves in the context of Foramen

In anatomy and osteology, a foramen (/fəˈrmən/; pl.: foramina, /fəˈræmɪnə/ or foramens /fəˈrmənz/; from Latin 'an opening produced by boring') is an opening or enclosed gap within the dense connective tissue (bones and deep fasciae) of extant and extinct amniote animals, typically to allow passage of nerves, arteries, veins or other soft tissue structures (e.g. muscle tendon) from one body compartment to another.

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Nerves in the context of Cauda equina syndrome

Cauda equina syndrome (CES) is a condition that occurs when the bundle of nerves below the end of the spinal cord known as the cauda equina is damaged. Signs and symptoms include low back pain, pain that radiates down the leg, numbness around the anus, and loss of bowel or bladder control. Onset may be rapid or gradual.

The cause is usually a disc herniation in the lower region of the back. Other causes include spinal stenosis, cancer, trauma, epidural abscess, and epidural hematoma. The diagnosis is suspected based on symptoms and confirmed by medical imaging such as MRI or CT scan.

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Nerves in the context of Clinical neurophysiology

Clinical neurophysiology is a medical specialty that studies the central and peripheral nervous systems through the recording of bioelectrical activity, whether spontaneous or stimulated. It encompasses both research regarding the pathophysiology along with clinical methods used to diagnose diseases involving both central and peripheral nervous systems. Examinations in the clinical neurophysiology field are not limited to tests conducted in a laboratory. It is thought of as an extension of a neurologic consultation. Tests that are conducted are concerned with measuring the electrical functions of the brain, spinal cord, and nerves in the limbs and muscles. It can give the precise definition of site, the type and degree of the lesion, along with revealing the abnormalities that are in question. Due to these abilities, clinical neurophysiology is used to mainly help diagnose diseases rather than treat them.

In some countries it is a part of neurology or psychiatry, for example the United States and Germany. In other countries it is an autonomous specialty, such as Spain, Portugal, Italy, the United Kingdom, Finland, Sweden and Norway.

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