Fiber (redirected from autonomic nerve fibers)

fiber /fi·ber/ (fi´ber)

1. an elongated, threadlike structure.

2. nerve f.

3. dietary f.

---

A fibers  myelinated afferent or efferent fibers of the somatic nervous system having a diameter of 1 to 22 µm and a conduction velocity of 5 to 120 meters per second; they include the alpha, beta, delta, and gamma fibers.

accelerating fibers , accelerator fibers adrenergic fibers that transmit the impulses which accelerate the heart beat.

adrenergic fibers  nerve fibers, usually sympathetic, that liberate epinephrine or related substances as neurotransmitters.

afferent fibers , afferent nerve fibers nerve fibers that convey sensory impulses from the periphery to the central nervous system.

alpha fibers  motor and proprioceptive fibers of the A type, having conduction velocities of 70 to 120 meters per second and ranging from 13 to 22 µm in diameter.

alveolar fibers  fibers of the periodontal ligament extending from the cementum of the tooth root to the walls of the alveolus.

arcuate fibers  the bow-shaped fibers in the brain, such as those connecting adjacent gyri in the cerebral cortex, or the external or internal arcuate fibers of the medulla oblongata.

association fiber  one of the nerve fibers connecting different cortical areas within one hemisphere.

autonomic nerve fibers  nerve fibers that innervate smooth muscle and glandular tissues, either stimulating and activating the muscle or tissue (autonomic efferent f's) or receiving sensory impulses from them (autonomic afferent f's) .

B fibers  myelinated preganglionic autonomic axons having a fiber diameter of = 3 µm and a conduction velocity of 3 to 15 meters per second; these include only efferent fibers.

basilar fibers  those that form the middle layer of the zona arcuata and the zona pectinata of the organ of Corti.

beta fibers  motor and proprioceptive fibers of the A type, having conduction velocities of 30 to 70 meters per second and ranging from 8 to 13 µm in diameter.

C fibers  unmyelinated postganglionic fibers of the autonomic nervous system, also the unmyelinated fibers at the dorsal roots and at free nerve endings, having a conduction velocity of 0.6 to 2.3 meters per second and a diameter of 0.3 to 1.3 µm.

collagen fibers , collagenous fibers the soft, flexible, white fibers which are the most characteristic constituent of all types of connective tissue, consisting of the protein collagen, and composed of bundles of fibrils that are in turn made up of smaller units (microfibrils), which show a characteristic crossbanding with a major periodicity of 65 nm.

commissural fiber  one of the nerve fibers which pass between the cortex of opposite hemispheres of the brain, or between two sides of the brain stem or spinal cord.

dietary fiber  that part of whole grains, vegetables, fruits, and nuts that resists digestion in the gastrointestinal tract; it consists of carbohydrate (cellulose, etc.) and lignin.

efferent fibers , efferent nerve fibers nerve fibers that convey motor impulses away from the central nervous system toward the periphery.

elastic fibers  yellowish fibers of elastic quality traversing the intercellular substance of connective tissue.

fusimotor fibers  efferent A fibers that innervate the intrafusal fibers of the muscle spindle.

gamma fibers  any A fibers that conduct at velocities of 15 to 40 meters per second and range from 3 to 7 µm in diameter, comprising the fusimotor fibers.

gray fibers  unmyelinated nerve fibers found largely in the sympathetic nerves.

insoluble fiber  that not soluble in water, composed mainly of lignin, cellulose, and hemicelluloses and primarily found in the bran layers of cereal grains.

intrafusal fibers  modified muscle fibers which, surrounded by fluid and enclosed in a connective tissue envelope, compose the muscle spindle.

Mahaim fibers  specialized tissue connecting components of the conduction system directly to the ventricular septum.

motor fibers  efferent fibers.

Müller's fibers  elongated neuroglial cells traversing all the layers of the retina, forming its principal supporting element.

muscle fiber  any of the cells of skeletal or cardiac muscle tissue. Skeletal muscle fibers are cylindrical multinucleate cells containing contracting myofibrils, across which run transverse striations. Cardiac muscle fibers have one or sometimes two nuclei, contain myofibrils, and are separated from one another by an intercalated disk; although striated, cardiac muscle fibers branch to form an interlacing network.

myelinated fibers  grayish white nerve fibers whose axons are encased in a myelin sheath, which may in turn be enclosed by a neurilemma.

nerve fiber  a slender process of a neuron, especially the prolonged axon which conducts nerve impulses away from the cell; classified as either afferent or efferent according to the direction the impulses flow, and either myelinated or unmyelinated according to whether there is or is not a myelin sheath.

osteogenetic fibers , osteogenic fibers precollagenous fibers formed by osteoclasts and becoming the fibrous component of bone matrix.

preganglionic fibers  the axons of preganglionic neurons.

pressor fibers  nerve fibers which, when stimulated reflexly, cause or increase vasomotor tone.

projection fiber , projection nerve fibers one of the nerve fibers that connect the cerebral cortex with the subcortical centers, the brain stem, and the spinal cord.

Purkinje fibers  modified cardiac muscle fibers composed of Purkinje cells, occurring as an interlaced network in the subendothelial tissue and constituting the terminal ramifications of the cardiac conducting system.

radicular fibers  fibers in the roots of the spinal nerves.

reticular fibers  immature connective tissue fibers staining with silver, forming the reticular framework of lymphoid and myeloid tissue, and occurring in interstitial tissue of glandular organs, the papillary layer of the dermis, and elsewhere.

sensory fibers  afferent fibers.

Sharpey's fibers 

1. collagenous fibers that pass from the periosteum and are embedded in the outer circumferential and interstitial lamellae of bone.

2. terminal portions of principal fibers that insert into the cementum of a tooth.

soluble fiber  that with an affinity for water, either dissolving or swelling to form a gel; it includes gums, pectins, mucilages, and some hemicelluloses, and is primarily found in fruits, vegetables, oats, barley, legumes, and seaweed.

somatic nerve fibers  nerve fibers that stimulate and activate skeletal muscle and somatic tissues (somatic efferent f's) or receive impulses from them (somatic afferent f's) .

spindle fibers  the microtubules radiating from the centrioles during mitosis and forming a spindle-shaped configuration.

traction fibers  spindle f's.

unmyelinated fibers  nerve fibers that lack the myelin sheath.

vasomotor fibers  unmyelinated nerve fibers going chiefly to arteriolar muscles.

visceral nerve fibers  autonomic nerve f's.

white fibers  collagenous f's.

---

fi·ber (fbr)

n.

1. A slender thread or filament.

2. Extracellular filamentous structures such as collagenic or elastic connective tissue fibers.

3. The nerve cell axon with its glial envelope.

4. An elongated threadlike cell, such as a muscle cell or one of the epithelial cells of the lens of the eye.

5. Coarse, indigestible plant matter, consisting primarily of polysaccharides such as cellulose, that when eaten stimulates intestinal peristalsis. Also called roughage.

---

Fiber

Carbohydrate material in food that cannot be digested.

Mentioned in: Laxatives

---

fiber,

n threadlike structure found in various plant and animal tissues.

fiber, small myelinated,

n See A-delta fiber.

fiber, soluble,

n one of three types of fiber; soluble fibers are pectin, gum mucilage, and glucomannan and are found in pears, apples, vegetables, and wheat bran.

fiber, sweeping cross,

n massage technique that closely resembles gliding or effleurage. Distinguished by the addition of light cross-fiber strokes (direction of movement is perpendicular to the pattern of muscle fibers) that penetrate deeper tissues. See also effleurage.

Fiber, sweeping cross.

fiber, unmyelinated (unˈ·mīˑ··l·nāˈ· tid fīˑ·ber),

n a neuron that is not surrounded by a myelin sheath.

---

fiber(s),

n an elongated, threadlike structure of organic tissue.

fibers, A-alpha nerve,

n.pl the large-diameter nerve fibers that connect into the substantia gelatinosa of the dorsal horns of the spinal cord before synapsing with the central transmission of the dorsal horn. A-alpha fibers are associated with the “gate-control” theory of pain.

fibers, A-beta nerve,

n.pl the large-diameter nerve fibers that are mechanoreceptors for pressure occurring in both the pulp and periodontal ligament, necessary to operate the gate mechanism.

fibers, A-delta nerve,

n.pl the small-diameter nerve fibers that are mechanoreceptors for pain occurring in both the pulp and the periodontal ligament, necessary to operate the gate mechanism.

fibers, adrenergic

(ad´rner´jik),
n.pl the nerve fibers, including most of the postganglionic sympathetic fibers, that transmit their impulses across synapses or neuroeffector junctions through the local release of the neurohormone, more recently identified as
norepinephrine and formerly designated
sympathin.

fibers, alveolar,

n.pl the collagen fibers of the periodontal ligament that extend from the alveolar bone to the intermediate plexus, where their terminations are interspersed with the terminations of the cemental group of fibers.

fibers, alveolar crest,

n.pl the collagen fibers of the periodontal ligament that extend from the cervical area of the tooth to the alveolar crest.

fibers, alveolgingival,

n.pl the collagen fibers of the periodontal ligament that extend from the alveolar crest into the gingiva.

fibers, apical,

n.pl the collagen fibers of the periodontal ligament radiating apically from tooth to bone.

fibers, association,

n.pl the extensions of nerve cells that are neither efferent nor afferent neurons but furnish a pathway of connection between them.

fibers, bundle,

n.pl the gathering together of collagen fibers in a group, particularly the collagen fiber bundles of the periodontal ligament.

fibers, C nerve,

n.pl the small-diameter nerve fibers that are mechanoreceptors for pain occurring in both the pulp and the periodontal ligament, necessary to operate the gate mechanism.

fibers, cemental,

n.pl the collagen fibers of the periodontal ligament extending from the cementum to the zone of the intermediate plexus, where their terminations are interspersed with the terminations of the alveolar group of periodontal fibers.

fibers, circular,

n.pl the collagen fibers in the free gingiva that encircle the tooth in a ringlike fashion.

fibers, collagen,

n.pl white fibers composed of collagen. The most conspicuous part of connective tissue, including the gingivae and periodontal ligament. Some fibers are distributed haphazardly throughout the connective tissue ground substance, and others are arranged in coarse bundles that exhibit a distinct orientation. Characterized by its hydroxyproline and hydroxylysine content.

fiber, crestal,

n a group of collagen fibers of the periodontal ligament extending from the cervical area of the tooth to the alveolar crest.

fibers, dentogingival,

n.pl the fan-shaped fibers of the periodontal ligament that emerge from the supraalveolar connective tissue; composed of circular, dentogingival, dentoperiosteal, and transseptal (interdental) fiber groups.

fibers, dentoperiosteal,

n the part of the fibers of the periodontal ligament that emerge from the supraalveolar part of the cementum of the tooth and pass outward beyond the alveolar crest in an apical direction into the mucoperiosteum of the attached gingiva.

fibers, gingival,

n the group of fibers of the periodontal ligament that belong to the gingival and supraalveolar connective tissue; composed of circular, dentogingival, dentoperiosteal, and transseptal fiber (interdental) groups.

fibers, horizontal,

n.pl the collagen fibers of the periodontal ligament that extend horizontally from the cementum to the alveolar bone.

fibers, interradicular,

n.pl the collagen fibers of the periodontal ligament noted in multirooted teeth that extend from the cementum to the bone between the roots.

fiber, myelinated nerve

n a nerve fiber inside or outside the brain that is covered with an insulating medullary sheath along which are located nodes of Ranvier that facilitate as relay points the speed of nerve impulses over that of an equivalent nonmedullated fiber.

fibers, nerve,

n.pl See fiber, myelinated nerve, and fiber, nonmedullated nerve.

fibers, nonmedullated nerve

(non´med´lā´td),
n a nerve fiber not covered by an insulating medullary sheath that is thus exposed to other tissue fluids and their respective electric potentials. In nonmedullated fibers, the impulse is relayed from point to contiguous point. Most of the nonmedullated fibers are within the substance of the central nervous system, and the distances between the cells are short.

Gingival fibers.

Tissues and fibers of the gingiva and attachment apparatus.

fibers, oblique,

n the group of collagen fibers in bundle arrangement in the periodontal ligament that are obliquely situated, with insertions in the cementum, and that extend more occlusally in the alveolus.

fibers, periodontal,

n See ligament, periodontal.

fibers, principal,

n.pl the numerous bundles of collagen fibers arranged in groups that function as the mode of attachment of the tooth to the alveolus and form the periodontal ligament.

fibers, Sharpey's,

n.pr the collagen fibers of the periodontal ligament that become incorporated into the cementum or alveolar bone.

fibers, transseptal,

n.pl a part of the collagen fibers of the periodontal ligament that extends from the supraalveolar cementum of one tooth horizontally through the interdental attached gingiva above the septum of the alveolar bone to the cementum of the adjacent tooth. Also called
interdental fibers.