medullary ray

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ray

 [ra]
a line emanating from a center, as a more or less distinct portion of radiant energy (light or heat), proceeding in a specific direction.
α-r's high-speed helium nuclei ejected from radioactive substances; they have less penetrating power than beta rays. See also alpha particles.
actinic r's light rays that produce chemical action, especially those beyond the violet end of the spectrum.
alpha r's α-rays.
β-r's (beta r's) electrons ejected from radioactive substances with velocities as high as 98 per cent of the velocity of light; they have more penetrating power than alpha rays but less than gamma rays. See also beta particles.
cosmic r's very penetrating radiations that apparently move through interplanetary space in every direction.
digital ray a digit of the hand or foot and corresponding metacarpal or metatarsal bone, regarded as a continuous unit.
γ-r's (gamma r's) a type of electromagnetic radiation emitted by an atomic nucleus during a nuclear reaction; see also gamma rays.
grenz r's very soft electromagnetic radiation of wavelengths of about 2 angstroms.
infrared r's radiations just beyond the red end of the visible spectrum, having wavelengths of 0.75–1000 μm; see also infrared.
medullary ray a cortical extension of a bundle of tubules from a renal pyramid.
roentgen r's x-rays.
ultraviolet r's radiant energy beyond the violet end of the visible spectrum, of wavelengths 0.39 to 0.18 μm; see also ultraviolet rays.
x-r's see x-rays.

med·ul·lar·y ray

[TA]
the center of the renal lobule, which has the shape of a small, steep pyramid, consisting of straight tubular parts; these may be either ascending or descending limbs of the nephronic loop or collecting tubules.

med·ul·lar·y ray

(med'ŭ-lar'ē rā) [TA]
The center of the renal lobule, which has the shape of a small, steep pyramid, consisting of straight tubular parts; these may be either ascending or descending limbs of the nephronic loop or collecting tubules.
Synonym(s): Ferrein pyramid.

medullary ray

a band of PARENCHYMA cells in plant roots and stems leading out from the centre along a radius and separating the vascular tissues, forming xylem rays and phloem rays in primary and secondary growth. Rays enable the transport of water and other materials across the stem or root. see SECONDARY THICKENING.

Ferrein,

Antoine, French anatomist, 1693-1769.
Ferrein canal - a space between the closed lids and the eyeball through which the tears flow to the punctum lacrimale. Synonym(s): rivus lacrimalis
Ferrein cords
Ferrein foramen - the opening on the anterior aspect of the petrous part of the temporal bone which leads to the facial canal and gives passage to the greater petrosal nerve. Synonym(s): hiatus of facial canal
Ferrein ligament - the capsular ligament that passes obliquely down and backward across the lateral surface of temporomandibular joint. Synonym(s): lateral temporomandibular ligament
Ferrein pyramid - the center of the renal lobule, which has the shape of a small, steep pyramid, consisting of straight tubular parts. Synonym(s): medullary ray; processus ferreini
Ferrein tube - Synonym(s): convoluted tubule of kidney
Ferrein vasa aberrantia - biliary canaliculi that are not connected with hepatic lobules.
processus ferreini - Synonym(s): Ferrein pyramid

ray

a line emanating from a center, as a more or less distinct portion of radiant energy (light or heat), proceeding in a specific direction.

alpha r's,
α-r's high-speed helium nuclei ejected from radioactive substances; they have less penetrating power than beta rays. See also alpha particles.
beta r's,
β-r's, beta particles electrons ejected from radioactive substances with velocities as high as 0.98 of the velocity of light; they have more penetrating power than alpha rays, but less than gamma rays.
digital ray
a digit of the hand or foot and corresponding metacarpal or metatarsal bone, regarded as a continuous unit.
ray fungus
branched filamentous appearance of Actinomyces bovis in granules in pus.
gamma r's,
γ-r's electromagnetic radiation of short wavelengths emitted by an atomic nucleus during a nuclear reaction, consisting of high-energy photons, having no mass and no electric charge, and traveling with the speed of light and with great penetrating power.
They have very great range in penetrating tissues and cytotoxic effects, especially on nuclei and on tissues which are replicating rapidly. The fetus, bone marrow, blood, liver and gonads are particularly susceptible. See also radiation injury, radiation therapy.
medullary ray
a cortical extension of a bundle of tubules from a renal pyramid.
roentgen r's
x-rays.
x-r's
see x-ray.
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