trapezoid body


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Related to trapezoid body: medial geniculate body, Lateral lemniscus, corpus trapezoideum

trap·e·zoid bod·y

[TA]
a plate of transverse fibers running over the posterior (deep) border of the pontine nuclei; it is formed by ascending auditory fibers that cross to the opposite side of the brainstem.
Synonym(s): corpus trapezoideum [TA], trapezoid (4) [TA]

trapezoid body

A transverse sheet of secondary sensory axons that originate in the cochlear nuclei and that cross the midline just dorsal to the pons in the rostral hindbrain. About half of the cochlear axons remain ipsilateral and ascend toward the inferior colliculus via the lateral lemniscus. Those cochlear axons that cross the cross the midline in the trapezoid body also join the (contralateral) lateral lemniscus and run toward the inferior colliculus.
See also: body

trapezoid body

A transverse sheet of secondary sensory axons that originate in the cochlear nuclei and that cross the midline just dorsal to the pons in the rostral hindbrain. About half of the cochlear axons remain ipsilateral and ascend toward the inferior colliculus via the lateral lemniscus. Those cochlear axons that cross the cross the midline in the trapezoid body also join the (contralateral) lateral lemniscus and run toward the inferior colliculus.

body

1. the trunk, or animal frame, with its organs.
2. the largest and most important part of any organ.
3. any mass or collection of material.

acetone b's
see ketone bodies.
body cavity
see cavity.
ellipsoid body
formed in degenerating myelin sheaths. Each contains a fragment of myelin apparently undergoing enzymatic digestion around a fragment of degenerating axon.
fimbriate body
see corpus fimbriatum.
body fluids
see body fluids.
gelatinous body
a 3-5 mm glycogen-rich body in the dorsal surface of the lumbosacral enlargement of the spinal cord in birds.
geniculate b's (lateral)
two metathalamus eminences, one on each side just lateral to the medial geniculate bodies, marking the termination of the optic tract.
geniculate b's (medial)
two metathalamus eminences, one on each side, just lateral to the superior colliculi, concerned with hearing.
Heinz body, Heinz-Ehrlich body
a dark staining refractile body of erythrocytes, consisting of denatured hemoglobin. See also Heinz body anemia.
Howell's b's
body louse
mamillary body
either of the pair of small spherical masses in the interpeduncular fossa of the midbrain, forming part of the hypothalamus.
body mass
see body weight.
multilamellar body
any of the osmiophilic, lipid-rich, layered bodies found in the type II alveolar cells of the lung.
Negri b's
eosinophilic, oval or round inclusion bodies in the cytoplasm of neurones of animals dead of rabies.
olivary body
see olive (2).
Pappenheimer body
dark, basophilic, iron-containing granules seen in erythrocytes (siderocytes). Occur in hemolytic anemia.
para-aortic b's
enclaves of chromaffin cells near the sympathetic ganglia along the abdominal aorta, which secrete catecholamines during prenatal and early postnatal life, aiding the adrenal medulla. Tumors of these structures produce clinical signs similar to those of pheochromocytoma.
paracloacal vascular body
a small patch of vascular tissue in the wall of the urodeum in birds.
phallic body
pair of bodies flanking the phallus of the male bird; participate in the insemination of the hen.
pituitary body
pituitary gland.
quadrigeminal b's
see corpora quadrigemina.
striate body
see corpus striatum.
body surface area (BSA)
the total surface area of the body. Used to calculate drug dosages, particularly in the use of toxic drugs such as those used in cancer chemotherapy. This minimizes errors introduced by variations in distribution, metabolism and excretion of the drug. Several equations can be used to express the area, based on body weight, but conversion tables are usually used. See Table 21.
trapezoid body
transverse ridge crossing the ventral surface of the medulla oblongata.
vitreous body
the transparent gel filling the posterior segment of the eyeball between the lens and retina. Called also vitreous and vitreous humor.
body weight
see body weight.
wolffian body