medullary ray

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

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.