Nervio

A nerve is an enclosed, cable-like bundle of axons (the long, slender projection of a neuron). A nerve also includes the glial cells that ensheath the axons in myelin. Neurons are sometimes called nerve cells, though this term is technically imprecise since many neurons do not form nerves. Neuronas motoras, or nerves innervate or activate muscles groups to perform. Contenido 1 Anatomía 2 Clinical importance 3 Ver también 4 Additional images Anatomy Nerves are part of the peripheral nervous system. Afferent nerves convey sensory signals to the central nervous system, for example from skin or organs, while efferent nerves conduct stimulatory signals from the central nervous system to the muscles and glands. Afferent and efferent nerves are often arranged together, forming mixed nerves. Most nerves connect to the central nervous system through the spinal cord. The twelve cranial nerves, sin embargo, connect directly to parts of the brain. Spinal nerves are given letter-number combinations according to the vertebra through which they connect to the spinal column. Cranial nerves are assigned numbers, usually expressed as Roman numerals from I to XII. Además, most nerves and major branches of nerves have descriptive names. Inside the central nervous system, bundles of axons are termed tracts rather than nerves. The signals that nerves carry, sometimes called nerve impulses, are also known as action potentials: rapidly (hasta 120 m/s) traveling electrical waves, which begin typically in the cell body of a neuron and propagate rapidly down the axon to its tip or "terminus." The signals cross over from the terminus to the adjacent neurotransmitter receptor through a gap called the synapse. Clinical importance Damage to nerves can be caused by physical injury, swelling (p. ej.. carpal tunnel syndrome), autoimmune diseases (p. ej.. Guillain-Barré syndrome), infección (neuritis), Diabetes, or failure of the blood vessels surrounding the nerve. Pinched nerves occur when pressure is placed on a nerve, usually from swelling due to an injury or pregnancy. Nerve damage or pinched nerves are usually accompanied by pain, numbness, debilidad, or paralysis. Patients may feel these symptoms in areas far from the actual site of damage, a phenomenon called referred pain. Referred pain occurs because when a nerve is damaged, signaling is defective from all parts of the area which the nerve receives input, not just the site of the damage. Neurologists usually first diagnose disorders of the nerves by a physical examination, including the testing of reflexes, andante, muscle weakness, directed movement, propiocepción, and the sense of touch. During the exam, the doctor asks questions about the patients' symptoms and medical history. The initial exam can be followed with tests such as nerve conduction study and electromyography (EMG). See also Connective tissue in the peripheral nervous system Dermatome (anatomy) Nerve agents Nerve block Nerve fiber Nerve injury Nervous system Neuronal oscillations Neuropathy Peripheral nerve injury Peripheral nerve injury classification Synapse Additional images Peripheral nerve, cross section Major nerves (also see Peripheral nervous system) Cranial nerves: I olfactory | II optic | III oculomotor | IV trochlear | V trigeminal | V1 ophthalmic (lagrimal, frontal, supratroclear, supraorbitario, nasociliary, ciliary ganglion) | V2 maxillary (sphenopalatine ganglion) | V3 mandibular (buccal - auriculotemporal - lingual - alveolar inferior - otic ganglion) | VI abducens | VII facial (chorda tympani, nervus intermedius) | VIII vestibulocochlear (cochlear, vestibular) | IX glossopharyngeal | X vagus (recurrent laryngeal, Alderman's nerve) | XI accessory | XII hypoglossal Posterior spinal nerves: greater occipital C1-C4 - Cervical plexus: lesser occipital | greater auricular | lesser auricular | phrenic | ansa cervicalis C5-C8, T1 - Brachial plexus: supraclavicular branches (dorsal scapular, supraescapular, long thoracic) | lateral cord (musculocutaneous, lateral antibrachial cutaneous, lateral head of median nerve) | medial cord (ulnar, medial head of median nerve, medial antibrachial cutaneous, medial brachial cutaneous) | posterior cord (axillary, radial) T2-T11: intercostal T12, L1-L5 - Lumbar plexus: iliohypogastric | ilioinguinal | genitofemoral | lateral femoral cutaneous | femoral | obturator S1-S4 - Sacral plexus: gluteal | posterior femoral cutaneous | tibial | sciatic | sural | common peroneal S2-S5 - Pudendal plexus: perforating cutaneous | pudendal | visceral | muscular | anococcygeal This box: view • talk • edit Nerves of head and neck: the cranial nerves I-IV: olfactory - optic - oculomotor - trochlear V: trigeminal: trigeminal ganglion V1: ophthalmic: lagrimal - frontal (supratroclear, supraorbitario) - nasociliary (long root of ciliary, long ciliary, infratrochlear, etmoidal posterior, etmoidal anterior) - ciliary ganglion (short ciliary) V2: maxilar: meníngea media - in the pterygopalatine fossa (zygomatic, zygomaticotemporal, zygomaticofacial, esfenopalatino, alveolar posterosuperior) in the infraorbital canal/infraorbital nerve (middle superior alveolar, alveolar superior anterior) on the face (inferior palpebral, external nasal, labial superior, infraorbital plexus) - pterygopalatine ganglion (deep petrosal, nerve of pterygoid canal) branches of distribution (palatine, nasopalatine, pharyngeal) V3: mandibular: nervus spinosus - medial pterygoid - anterior (maseterico, profundo temporal, buccal, lateral pterygoid) posterior (auriculotemporal, lingual, alveolar inferior, milohioideo, mental) - otic ganglion - submandibular ganglion VI: abducens VII: facial: nervus intermedius - geniculate - inside facial canal (greater petrosal, nerve to the stapedius, chorda tympani) at exit from stylomastoid foramen (auriculares posteriores, digastric - stylohyoid) on face (temporal, zygomatic, buccal, mandibular, cervical) viii: vestibulocochlear: cochlear (striae medullares, lateral lemniscus) - vestibular IX: glossopharyngeal: fasciculus solitarius - nucleus ambiguus - ganglios (superior, petrous) - tympanic - carotid sinus X: vagus: ganglios (jugular, nodose) - Alderman's nerve - in the neck (pharyngeal branch, superior laryngeal ext and int, recurrent laryngeal) in the thorax (pulmonary branches, esophageal plexus) - in the abdomen (gastric plexuses, celiac plexus, gastric plexus) XI: accessory XII: hypoglossal This box: view • talk • edit Nerves of head and neck: the cervical plexus superficial: (lesser occipital - greater auricular - cervical transversa - supraclavicular) - deep: (ansa cervicalis - phrenic) This box: view • talk • edit Nerves of upper limbs (primarily): the brachial plexus supraclavicular: dorsal scapular - supraescapular - to the subclavius - long thoracic infraclavicular: lateral cord: musculocutaneous (lateral cutaneous of forearm) - lateral pectoral - lateral head of median (anterior interosseous, palmar, common palmar digital, proper palmar digital) medial cord: medial pectoral - medial cutaneous of forearm - medial cutaneous of arm - ulnar (muscular branches, dorsal branch, palmar branch, superficial branch, deep branch) - medial head of median posterior cord: subscapular (upper, lower) - thoracodorsal - axillary (superior lateral cutaneous of arm) - radial (muscular, inferior lateral cutaneous of arm, posterior cutaneous of arm, posterior cutaneous of forearm, superficial branch, deep branch, posterior interosseous) cutaneous innervation of the upper limbs v·d·e Nerves – autonomic nervous system (sympathetic nervous system/ganglion/trunks and parasympathetic nervous system/ganglion) (TA A14.3, Georgia 9.968) Head/ cranial Sympathetic Ciliary ganglion: roots Sensory Sympathetic Short ciliary Parasympathetic Ciliary ganglion: roots Sensory Parasympathetic Short ciliary Pterygopalatine ganglion: deep petrosal nerve of pterygoid canal branches of distribution: greater palatine inferior posterior nasal branches lesser palatine nasopalatine medial superior posterior nasal branches pharyngeal Submandibular ganglion Otic ganglion Neck/ cervical Sympathetic paravertebral ganglia: Cervical ganglia Superior Middle Inferior Stellate ganglion prevertebral plexus: Cavernous plexus Internal carotid Chest/ thorax Sympathetic paravertebral ganglia: Thoracic ganglia prevertebral plexus: Cardiac plexus Esophageal plexus Pulmonary plexus Thoracic aortic plexus splanchnic nerves: cardiopulmonary thoracic cardiac nerves: Superior Middle Inferior Abdomen/ Lumbar Sympathetic paravertebral ganglia: Lumbar ganglia prevertebral ganglia: Celiac ganglia Aorticorenal Superior mesenteric ganglion Inferior mesenteric ganglion prevertebral plexus: Celiac plexus Hepatic Splenic Pancreatic aorticorenal Abdominal aortic plexus Renal/Suprarenal Superior mesenteric Gastric Inferior mesenteric Spermatic Ovarian Superior hypogastric hypogastric nerve Superior rectal Inferior hypogastric Vesical Prostatic / Cavernous nerves of penis Uterovaginal Middle rectal splanchnic nerves: Lumbar splanchnic nerves Enteric Meissner's plexus Auerbach's plexus Pelvis/ sacral Sympathetic paravertebral ganglia: Sacral ganglia Ganglion impar splanchnic nerves: Sacral splanchnic nerves Parasympathetic splanchnic nerves: Pelvic splanchnic nerves {| clase="navbox collapsible uncollapsed nowraplinks" estilo="margen:auto; " [. v]·[. d]·[. e] M: PNS anat(h/r/t/c/b/l/s/a)/phys(r)/devp/prot/nttr/nttm/ntrp noco/auto/cong/tumr, sysi/epon, injr proc, droga(N1B) |} This box: view • talk • edit Nerves of lower limbs and lower torso: the lumbosacral plexus lumbar plexus: iliohypogastric - ilioinguinal - genitofemoral (femoral branch/lumboinguinal, genital branch) - lateral cutaneous of thigh (patellar) - obturator (anterior, cutaneous, posterior, accessory) - femoral (anterior cutaneous branches, saphenous) sacral/coccygeal plexus: to quadratus femoris - to obturator internus - to the piriformis - superior gluteal - inferior gluteal - posterior cutaneous of thigh (inferior cluneal, perineal branches) sciatic: tibial (medial sural cutaneous, sural, medial calcaneal, medial plantar, lateral plantar) - common fibular (lateral sural cutaneous, deep fibular, superficial fibular, medial dorsal cutaneous, intermediate dorsal cutaneous) pudendal plexus: perforating cutaneous - pudendal (dorsal of the penis/clitoris, inferior anal, perineal and posterior scrotal/labial) - anococcygeal cutaneous innervation of the lower limbs This page uses Creative Commons Licensed content from Wikipedia (ver autores).

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