fiber (fi'ber) [L. fibra, filament, fiber]
1. A threadlike or filmlike structure, e.g., a nerve fiber.
2. A neuron or its axonal portion.
3. An elongated threadlike structure. It may be cellular as nerve fiber or muscle fiber, or may be a cellular product, as collagen, elastic, oxytalan, or reticular fiber.
A slender cellulosic structure derived from plants such as cotton. See: rayon, purified
A heavily myelinated, fast-conducting nerve fiber.
A sympathetic nerve fiber that carries impulses to increase heart rate.
A nerve fiber that carries sensory impulses to the central nervous system from receptors in the periphery.
Any preganglionic fiber, postganglionic parasympathetic fiber, postganglionic sympathetic fiber to a sweat gland, or efferent fiber to skeletal muscle.
Collagen bundles in the gingiva that surround a tooth.
An excitatory axon from the inferior olivary nucleus that synapses with dendrites of Purkinje cells in the cerebellar cortex
A nerve that decreases arterial muscle tone and, as a result, lowers blood pressure.
The components of food that resist chemical digestion, including cellulose, hemicellulose, lignin, gums, mucilages, and pectin. Dietary fibers are classified according to their solubility in water.
Water-insoluble fibers include cellulose, lignin, and some hemicelluloses. These substances can soften and increase the bulk of the bowel movement. Natural gel-forming fibers found in fruits and vegetables such as gums, mucilages, and some hemicelluloses are water soluble. Most foods of plant origin contain both soluble and insoluble dietary fiber. Many disease processes including constipation, diabetes mellitus, gallstones, hemorrhoids, high blood pressure, irritable bowel syndrome, and obesity have been shown to be ameliorated by a high-fiber diet. There are epidemiological data supporting the existence of an inverse relationship between the disease and dietary fiber consumption. The relation between fiber intake and colorectal cancer is complex; some studies suggest that fiber intake is protective, while others suggest that it is not.
Foods rich in fiber include whole-grain foods, bran flakes, beans, fruits, leafy vegetables, nuts, root vegetables and their skins.
A nerve fiber that carries motor impulses from the central nervous system to effector organs.
The muscle fibers surrounding a muscle spindle.
fermentable fiberSoluble fiber.
Collagen fibers that support the marginal or interdental gingiva and are adapted to the tooth surface.
A nerve fiber that carries impulses to decrease heart rate.
Any dietary fiber that does not dissolve in water. Insoluble dietary fiber includes hemicellulose, cellulose, and lignin. An example is wheat bran.
An intercrural fiber, part of the superficial inguinal ring.
The collagen fibers of the periodontal ligament in the interradicular area, attaching the tooth to alveolar bone.
intrafusal muscle fiber
The structural component of the muscle spindle, made up of small skeletal muscle fibers at either end and a central noncontracile region where the sensory receptors are located.
James fibers See: James fibers
Mahaim fibers See: Mahaim fibers
A synthetic fiber made from chemicals (e.g., rayon or polyester). Synonym: synthetic fiber
An obsolete term for a myelinated neuron.
Müller fibers See: Müller, Heinrich
An excitatory axon from outside the cerebellum that synapses in the granular layer of the cerebellar cortex. Mossy fiber terminals are the central elements in complex synaptic formations that include dendrites of granular neurons and neurites of Golgi cells.
Any of the axons of motor neurons that innervate skeletal muscles.
A muscle cell in striated, smooth, or cardiac muscle.
A nerve fiber whose axon (dendrite) is wrapped in a myelin sheath.
nerve fiber See: nerve fiber
nigrostriatal fibersNigrostriate bundle.
nonmedullated fiberUnmyelinated fiber.
Bundles of thin, acid-resistant fibrils found in the periodontium.
The axon of a preganglionic neuron.
The major fiber groups of the functioning periodontium. They attach the tooth to the bone and adjacent teeth.
Axons that connect regions of the spinal cord.
Purkinje fiber See: Purkinje, Johannes E. von
Any of the extremely fine argyrophilic (silver-staining) fibers found in reticular tissue.
A peripheral motor nerve fiber that innervates glands and stimulates secretion.
Sharpey's fibers See: Sharpey, William
Sharpey's perforating fibers See: Sharpey, William
Any dietary fiber that dissolves in water. Soluble fiber is metabolized by bacteria in the gastrointestinal tract into short chain fatty acids, which in turn nourish commensal bacteria in the gut. Examples include most fruit and vegetable fibers, e.g., pectins, barley, cereal grains, cornmeal, and oats. See: fermentable fiber
synthetic fiberMan-made fiber.
Any of the collagenous fibers that extend between the teeth and are embedded in the cementum of adjacent teeth.
A nerve fiber that lacks a myelin sheath, although a neurilemma may be present in the peripheral nervous system.
Any of the interlacing fibers of the zonula ciliaris.