medullary ray (redirected from Medullary rays)

medullary ray

n.

The center of the renal, cortical lobule, consisting of the ascending or descending limbs of the nephronic loop or of the collecting tubules. Also called Ferrein's pyramid.

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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.

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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.

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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.