Efferent nerves

Efferent nerves

Nerves that convey impulses away from the central nervous system to the periphery.

Mentioned in: Rabies

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efferent (ef´rnt),

adj conveying away from a center toward the periphery.

efferent nerves,

n.pl See nerves, efferent.

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nerve,

n a cordlike structure that conveys impulses between a part of the central nervous system and some part of the body and consists of an outer connective tissue sheath and bundles of nerve fibers. See also each of the individual nerves of the head and neck as they are listed.

nerve, abducent (VI),

n the sixth cranial nerve; a small, completely motor nerve arising in the pons, supplying the lateral rectus muscle of the eye.

nerve, accessory,

n See nerve, spinal accessory.

nerve, acoustic (VIII),

n the eighth cranial nerve; the vestibulocochlear nerve; a sensory nerve consisting of a vestibular portion and an auditory (or cochlear) portion.

nerve(s), afferent, in pulp,

n any nerve that originates as a terminal free nerve ending in the dental pulp tissue and travels to the second and third divisions (maxillary nerve and mandibular nerve) of the cranial trigeminal nerve (cranial nerve V).

nerve, alveolar,

n afferent nerves that convey impulses from the pulp tissue and periodontium of the maxillary teeth to the maxillary division of the cranial trigeminal nerve.

nerve, anterior superior alveolar,

n alveolar nerve that conveys impulses from the pulp tissue and periodontium of the maxillary anterior teeth to the infraorbital nerve.

nerve, auriculotemporal

n a nerve that transmits feeling from the external ear, scalp, and parotid salivary gland to the mandibular division of the cranial trigeminal nerve.

nerve, branchial,

n one of five cranial nerves that supply the derivatives of the branchial arches: trigeminal (V), facial (VII), glossopharyngeal (IX), vagus (X), and spinal accessory (XI). Each branchial nerve may have a variety of functions, including visceral motor and visceral and somatic sensory functions.

nerve, buccal (long),

n afferent nerve that conveys impulses from the facial periodontium of the mandibular molars and gingiva to the mandibular division of the cranial trigeminal nerve.

nerve, chiasma, optic,

n the decussation, or crossing, of optic nerve fibers from the medial side of the retina on one side to the opposite side of the brain.

nerve, chorda tympani

n a parasympathetic and special sensory branch of the facial nerve supplying the submandibular and sublingual glands and the anterior two thirds of the tongue (taste).

nerve, cochlear

n one of the two major branches of the eighth cranial nerve; a special sensory nerve for the sense of hearing that transmits impulses from the organ of Corti to the brain.

nerve, cranial,

n any one of 12 paired nerves, classified in three sets, arising directly in the brain and supplying various tissues of the head and neck. The cranial nerves are the special somatic sensory nerves: olfactory (I), optic (II), and vestibulocochlear (acoustic) (VIII); the somatic motor nerves: oculomotor (III), trochlear (IV), abducent (VI), and hypoglossal (XII); and the branchial nerves: trigeminal (V), facial (VII), glossopharyngeal (IX), vagus (X), and spinal accessory (XI).

nerve, deep temporal,

n an anterior and a posterior nerve that branch away from the mandibular nerve of the trigeminal nerve and extend deep into the temporalis muscle, which is used during mastication.

nerve degeneration,

n the reversion to a less organized and functioning state, usually detected by the loss of ability to conduct or transmit nerve impulses. Advanced degeneration might show cellular decomposition.

nerve ending,

n the terminal of a nerve fiber, usually in synapse with another fiber or in a sensory organ.

nerve, facial (VII),

n the seventh cranial nerve; a mixed nerve supplying motor fibers to the facial muscles, the stapedius, and posterior body of the digastric; sensory fibers from the taste buds in the anterior two thirds of the tongue (via the chorda tympani); and general visceral autonomic fibers for the submandibular and sublingual salivary glands. It travels unilaterally over the face and at one point is located in the parotid salivary gland, which it does not serve. However, pain in the parotid gland indicates a glandular malignancy, and complications with an inferior nerve block can also result from its location there.

The cranial nerves.

nerve fiber,

n a slender process of a neuron, usually the axon. Each fiber is classified as myelinated or unmyelinated.

nerve, frontal,

n afferent nerve from the union of the superorbital and supratrochlear nerves that carries information from the forehead, scalp, nose, and upper eyelids to the ophthalmic division of the cranial trigeminal nerve.

nerve, glossopharyngeal (IX)

n the ninth cranial nerve; a mixed motor and sensory nerve arising in the medulla and supplying motor efferents to stylopharyngeal muscles and other pharyngeal muscles; visceral motor efferents via the otic ganglion for the parotid gland; special visceral afferents from the taste buds in the posterior third of the tongue; and general sensory afferents from the pharynx and posterior aspects of the oral cavity. It is essential to the sense of taste.

nerve, greater (anterior) palatine,

n the nerve originating in the pterygopalatine ganglion that supplies the hard palate, part of the soft palate, and its associated lingual mucosa.

nerve, greater petrosal

n one of the two nerves that branch off of the facial nerve and help control the muscles used in facial expression; this nerve also carries impulses to the lacrimal gland and the nasal cavity, and to and from the palate. The nerve has both afferent and efferent fibers.

nerve, hypoglossal (XII),

n the twelfth cranial nerve; a motor nerve that arises in the medulla and supplies extrinsic and intrinsic muscles of the tongue. Each nerve has four major branches, communicates with the vagus nerve, and connects to the nucleus XII in the brain.

nerve, incisive,

n afferent nerve that merges with the mental nerve to later create the inferior alveolar nerve in the mandibular canal. This nerve transmits feeling from the pulp tissue and facial periodontium of the mandibular anterior teeth and premolars to the mandibular division of the cranial trigeminal nerve.

nerve, inferior alveolar,

n a motor and general sensory branch of the mandibular nerve, with mylohyoid, inferior dental, mental, and inferior gingival branches.

nerve, infraorbital,

n afferent nerve that enters through the infraorbital foramen and canal to merge with the maxillary branch of the cranial trigeminal nerve.

nerve, intermediate,

n the parasympathetic and special sensory division of the facial nerve with chorda tympani and greater petrosal branches.

nerve, lacrimal,

n afferent nerve that is part of the ophthalmic division of the cranial trigeminal nerve and controls secretions in the upper eyelid, lacrimal gland, and the conjunctiva.

nerve, lingual,

n a general sensory branch of the mandibular nerve having sublingual and lingual branches and connections with the hypoglossal nerve and chorda tympani.

nerve, mandibular,

n the mandibular division of the trigeminal nerve, arising in the trigeminal ganglion and supplying general sensory and motor fibers via mesenteric, pterygoid, buccal, auriculotemporal, deep temporal, lingual, inferior alveolar, and meningeal branches.

nerve, maxillary,

n the maxillary division of the trigeminal nerve arising in the trigeminal ganglion and supplying general sensory fibers via zygomatic, posterosuperior alveolar, infraorbital, pterygopalatine, and nasopalatine branches.

nerve, mental,

n a nerve that branches off the inferior alveolar nerve, emerging from the mandible through the mental foramen and branching further to provide sensory innervation to the tissues of the chin and lower lip and the labial mucosa of the mandibular premolars and anterior teeth.

nerve, middle superior alveolar,

n alveolar nerve that conveys impulses from the pulp tissue and periodontium of the gingiva and the maxillary premolar teeth to the infraorbital nerve. This nerve is not always present in all persons. If not present, the premolars are innervated by the posterior superior alveolar nerve.

nerve, mylohyoid,

n a branch of the mandibular division of the cranial trigeminal nerve that serves the mylohyoid and digastric muscles of the oral cavity. It is thought to be a possible alternative innervation for the pulp tissues of the mandibular first molar in some cases.

nerve, nasociliary

n one of three branches of the cranial trigeminal nerve that controls parts of the eyes, nasal cavity, and paranasal sinuses.

nerve, nasopalatine

n afferent nerve that conveys impulses from the lingual periodontium of the maxillary anterior teeth bilaterally and the anterior hard palate to the maxillary division of the cranial trigeminal nerve.

nerve, oculomotor (III)

n the third cranial nerve; primarily a motor nerve arising from the midbrain and supplying motor efferents to the superior rectus, medial rectus, inferior rectus, and inferior oblique eye muscles, as well as autonomic fibers via the ciliary ganglion to the ciliary body and the iris.

nerve, olfactory (I)

n the first cranial nerve; a special sensory nerve for the sense of smell.

nerve, ophthalmic

n the ophthalmic division of the trigeminal nerve, arising in the trigeminal ganglion and supplying general sensory fibers via the frontal, lacrimal, and nasociliary branches.

nerve, optic (II),

n the second cranial nerve; a special sensory nerve for vision. It consists mainly of coarse, myelinated fibers that arise in the retinal ganglionic layer of the eye, traverse the thalamus, and connect with the visual cortex of the brain.

nerve, palatine,

n the two afferent nerves of the maxillary division of the cranial trigeminal nerve. The greater palatine nerve innervates the posterior hard palate and lingual periodontium of the maxillary molar teeth, while the lesser palatine nerve innervates the soft palate and palatine tonsillar tissue.

nerve, posterior superior alveolar,

n alveolar nerve that conveys impulses from the maxillary sinus, gingiva, pulp tissue, and periodontium of the maxillary molar teeth to the infraorbital nerve or to the maxillary nerve directly.

nerve regeneration,

n the reconstruction and renewal of cell structure and function; generally restricted to myelinated nerve fibers.

nerve repositioning,

n the surgical redirecting of the inferior alveolar and/or mental nerve to allow longer implants to be placed in a mandible that has extensive deterioration of the posterior ridge. Some temporary or long-term loss of sensation to the lip, tongue, chin and/or gingival tissue may result. Also known as
nerve lateralization and
nerve transpositioning.

nerve(s), somatic motor,

n (cranial), the somatic motor nerves–oculomotor (III), trochlear (IV), abducent (VI), and hypoglossal (XII)–largely comparable to the ventral motor roots of the spinal nerves. They are composed almost entirely of somatic motor fibers that emerge ventrally from the brainstem. Their arrangement is closely correlated with the distribution of the myotomes in the head. The oculomotor, trochlear, and abducent nerves, which supply the eye musculature, have the same myotomic origin and arrangement as the somatic muscles of the trunk and extremities.

nerve(s), special somatic sensory,

n the structural arrangements from typical sensory nerves by which the three main sense organs, nose, eyes, and ears, are innervated. The sensory nerves are the olfactory (I), optic (II), and vestibulocochlear (acoustic) nerves (VIII).

nerve(s), spinal,

n any one of 31 pairs of mixed peripheral nerves (8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal) that are connected segmentally with the spinal cord, dorsal sensory trunk, and ventral motor root.

nerve, spinal accessory (XI),

n the eleventh cranial nerve; a motor nerve that derives its origin in part from the medulla and in part from the cervical spinal cord. Its internal ramus joins with the vagus nerve to supply some of the muscles of the larynx. Its external ramus joins with the spinal nerves to supply the sternocleidomastoid and trapezius muscles. The nerve and its relationship to head posture is important in maintaining stable occlusal relationships of vertical dimension and centric relation.

nerve, tensor tympani,

n a small motor branch of the mandibular nerve.

nerve, trigeminal (V)

n the fifth cranial nerve; a mixed motor and sensory nerve connected with the pons through three roots (motor, proprioceptive, and large sensory), the latter root expanding into the trigeminal ganglion, from which arise the ophthalmic, masseteric, and mandibular divisions. It serves the muscles of mastication and cranial muscles through its motor root and serves the teeth, tongue, and oral cavity and most of the facial skin through its sensory root.

nerve, trochlear (IV)

n the fourth cranial nerve; a small motor nerve arising ventrally in the midbrain and supplying the inferior oblique muscle of the eye.

nerve trunk,

n a particularly sizeable bundle of axons or nerve fibers.

nerve, vagus (X)

n the tenth cranial nerve; a mixed parasympathetic, visceral, afferent, motor, and general sensory nerve with laryngeal, pharyngeal, bronchial, esophageal, gastric, and many other branches.

nerve, vestibular (VIII),

n one of the two major branches of the eighth cranial nerve; a special sensory nerve for the sense of balance and the transmission of space-orientation impulses from the semicircular canals to the brain.

nerve, vestibulocochlear (VII),

n the seventh cranial nerve; acoustic nerve; a sensory nerve consisting of a vestibular portion and an auditory, or cochlear, portion.

nerve, zygomatic

n the afferent nerve of the maxillary division of the cranial trigeminal nerve that serves the skin of the cheek and temple. It also innervates the lacrimal gland.

nerve(s), dentinal,

n any of the afferent or sensory neurons associated with the odontoblastic processes in the dentinal tubules and the attached cell body of the odontoblasts within the pulp tissue. These nerves may allow for an awareness of pain due to their monitoring of environmenal changes within the dentin. There is some controversy about their overall location in the dentin tubule (full length, partial, or not at all).

nerves, efferent,

n motor nerves that carry impulses from the brain or spinal cord toward the periphery of the body to activate muscles, usually in response to impulses received from sensory nerves.

nerve(s), periodontal ligament,

n the sympathetic fibers of the autonomic nervous system with enclosed nerve endings that control blood flow within the vessels and register pressure changes. Sensory or afferent fibers with free nerve endings cause an awareness of pain.

nerve(s), pulp,

n the sympathetic fibers of the autonomic nervous system located within the tissue that control blood flow within the vessels. Sensory or afferent fibers with free nerve endings in close proximity to the odontoblasts may cause an awareness of pain.