implantation cone |
<cell biology> Tapering region between a neuron's cell body and its axon. This region is responsible for summating the graded inputs from the dendrites and producing action potentials if the threshold is exceeded.
(12 Mar 1998) |
inverted cone bur |
A rotary cutting instrument in the shape of a truncated cone with the smaller end attached to the shaft; generally used for entering carious pits or creating undercuts in cavity preparations.
(05 Mar 2000) |
ocular cone |
The cone of light in the interior of the eyeball with the base formed by the rays entering through the pupil and the apex focused on the retina.
(05 Mar 2000) |
outer cone fibre |
Located between the inner segment and the cell body.
(05 Mar 2000) |
theca interna cone |
The conical thickening of thecal cells of an ovarian follicle with its apex pointed toward the surface.
(05 Mar 2000) |
elastic cone |
Thicker lower portion of the elastic membrane of the larynx, extending between the cricoid cartilage and the vocal ligaments, the latter actually being a thickening of the free, superior margin of the conus elasticus.
Synonym: cricovocal membrane, elastic cone.
Synonym: cricothyroid ligament.
(05 Mar 2000) |
twin cone |
Two retinal cone's fused together.
(05 Mar 2000) |
l-cone |
Long wavelength sensitive cone (red cone).
(05 Mar 2000) |
long cone technique |
The use of a cone distance of 14 inches or more in making oral roentgenographs.
(05 Mar 2000) |
loss cone |
In a magnetic mirror machine, particles with a large velocity parallel to the magneitc field and a small velocity perpendicular to the field will be able to escape past the magnetic mirror (see magnetic mirror). In that case the velocity distribution function (see distribution function) will be almost zero in the region of velocity space that allows particles to escape. The shape of that region (in a velocity space diagram with parallel velocity and perpendicular velocity as the axes) is a cone. When a particle undergoes a collision, its velocity gets somewhat randomised. Particles that are scattered into that cone are lost very quickly (in one mirror bounce time). Thus it is called a loss cone. Because of the loss cone, the theoretical maximum particle confinement time of a magnetic mirror machine can be only a few times the particle collision time, this is generally seen as a showstopper for mirror-based fusion research.
(09 Oct 1997) |
alternating light test |
Test to detect a relative afferent defect in one eye by watching pupillary movements.
With the patient fixing in the distance, the light is held on each eye for about a second, and quickly moved to the other eye. Assuming no defect of the innervation to the iris sphincter in one eye (which would produce an anisocoria in light), the eye with the weaker light response has a relative afferent pupillary defect.
This asymmetry of pupillomotor input can be estimated by holding neutral density filters in front of the better eye until the pupillary responses of the two eyes are balanced.
Synonym: swinging light test.
(05 Mar 2000) |
Begg light wire differential force technique |
An orthodontic appliance utilizing small gauge labial wires with expansion and contraction loops formed into it and attached to bands fitted to individual teeth; sometimes called Begg light wire differential force technique.
(05 Mar 2000) |
gene rearrangement, b-lymphocyte, light chain |
Ordered rearrangement of b-lymphocyte variable gene regions coding for the kappa or lambda light chains, thereby contributing to antibody diversity. It occurs during the second stage of differentiation of the immature b-lymphocyte.
(12 Dec 1998) |
ray, light |
<microscopy> The term applied to the lines perpendicular to the wavefronts of waves of light to indicate their direction of travel in an isotropic medium.
Note the wave normal and the ray do not coincide in isotropic media.
(05 Aug 1998) |
reflected light |
Light directed backward from a mirror.
(05 Mar 2000) |