Nerve Cord

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nerve cord

[′nərv ‚kȯrd]
(invertebrate zoology)
Paired, ventral cords of nervous tissue in certain invertebrates, such as insects or the earthworm.
Dorsal, hollow tubular cord of nervous tissue in chordates.

Nerve Cord


a structure within the central nervous system of annelids and arthropods. The nerve cord is situated on the ventral side of the body, under the gut. It is connected to the cerebral ganglia. The nerve cord consists of a pair of partially fused longitudinal nerve trunks, called connectives, and of pairs of segmental ganglia that innervate each of the body segments. The primitive form of the nerve cord, which occurs in some primitive annelids, polychaetes, and onychophorans, is scaliform, having widely spaced trunks and long commissures between the ganglia.

References in periodicals archive ?
Recently, the pan-neural synaptotagmin B monoclonal antibody generated from the sea star radial nerve cord has been used to great effect in studies of the LNS of echinoids, holothuroids, and asteroids (Nakajima et al.
Compared to the coronate larvae of ascophoran bryozoans, vesiculariform larvae are elongated in the aboral-oral axis, and the positions of the paraxial nerve cords and nerve nodule (Fig.
Some small differences in this genus include the bowed shape of the paraxial nerve cords, and the position and number of intercoronal cells on the larval surface.
As seen in a proposed hypothetical ancestral mollusc (Salvini-Plawen, 1972, 1985, 1991, 2006; Haszprunar, 1992), the nervous system of Caudofoveata is primitively tetraneurous, consisting of ventral (pedal) and lateral nerve cords extending from the cerebral ganglia (Fig.
One might assume that the many serially repeated swellings of the ventral and lateral nerve cords in the head region and trunk are an artifact caused by shrinkage of the body, because the longitudinal tracts (probably a mass of axonal bundles) are also repeatedly curved (e.
In addition to the axial nerve cord, four other, much smaller, nerve cords have been identified in the arms.
Unique to the octopus arm, stereotypical bend propagation can be evoked in an isolated arm by electrically stimulating the axonal tract of the arm nerve cord or by applying tactile stimulation to the skin or suckers.
number of nerve cords, fusion, distribution of neurotransmitters) can now be evaluated in light of the presumed primitiveness of the Dactylopodolidae.
Posterior nerve cords leaving circumpharyngeal ganglion (0 = multiple, 1 = 2 total)
Nerve cords were rinsed twice in a modified Leibovitz's L-15 medium, pinned out in ethanol-and UV-sterilized Sylgard-coated (Dow Corning) petri dishes (60 mm diameter), and then incubated in the modified medium.
Nerve cords were transferred from culture vessels to sterile, medium-filled, deep-well microscope slides that had a thin coat of Sylgard on their lower surfaces.
No large axons were visible in the dorsal region of abdominal nerve cord sections of Panulirus argus (Fig.