| ym-shift | <microbiology> The change in shape by dimorphic fungi when they shift from the yeast (Y) form in the animal body to the mould or mycelial form (M) in the environment. (09 Oct 1997) |
|---|---|
| luteoplacental shift | The change in site of production of the oestrogen and progesterone essential for human pregnancy from the corpus luteum to the placenta; ovariectomy always terminates pregnancy in most mammals because their placentas never produce enough oestrogen and progesterone, but, after the sixth week of pregnancy, a human placenta can produce enough of these hormones to prevent abortion despite ovariectomy. (05 Mar 2000) |
| axis | <botany> A stem, commonly used for the main stem of a whole plant or of an inflorescence. (09 Oct 1997) |
| axis bulbi externus | That part of the optic axis from the midpoint of anterior surface of the cornea to the posterior surface of the posterior pole of the external surface of the sclera. Synonym: axis bulbi externus. (05 Mar 2000) |
| axis bulbi internus | <anatomy> That part of the optic axis from the midpoint of the posterior surface of the cornea to the anterior surface of the retina opposite the posterior pole. Synonym: axis bulbi internus. (05 Mar 2000) |
| axis corpuscle | Axile corpuscle, the central portion of a tactile corpuscle. (05 Mar 2000) |
| axis, crystallographic | <microscopy> One of several imaginary lines assumed in describing the positions of the planes by which a crystal is bounded, the positions of the atoms in the structure of the crystal and the directions associated with vectorial and tensorial physical properties. (05 Aug 1998) |
| axis cylinder | An obsolete term for axon. (05 Mar 2000) |
| axis deviation | Deflection of the electrical axis of the heart to the right or left of the normal. See: left axis deviation, right axis deviation, axis. Synonym: axis shift. (05 Mar 2000) |
| axis fracture | <radiology> Incidence: 6% of cervical spine injuries, associated with atlas fractures in 8%, hyperflexion injury: odontoid fracture, type I avulsion of tip of odontoid (5-8%) difficult to detect, type II fracture through base of dens (54-67%) complication: nonunion, type III subdental injury (30-33%) prognosis: good, Differential diagnosis: os odontoideum, ossiculum terminale, hypoplasia/aplasia of dens, hyperextension injury: hangman's fracture (12 Dec 1998) |
| axis lentis | A line connecting the anterior and posterior poles of the lens of the eye. Synonym: axis lentis. (05 Mar 2000) |
| axis ligament of malleus | <anatomy> A ligament forming the axis about which the malleus rotates; it consists of two portions extending from the anterior and the posterior border, respectively, of the tympanic notch to the malleus. Synonym: axis ligament of malleus. (05 Mar 2000) |
| axis of lens | A line connecting the anterior and posterior poles of the lens of the eye. Synonym: axis lentis. (05 Mar 2000) |
| axis of symmetry | An axis through a particle (e.g., a virus) on such a plane that, if the particle is rotated on the axis, there are two or more positions at which the particle appears identical. (05 Mar 2000) |
| axis, optic | <microscopy> The direction, or directions in an anisotropic crystal along which light is not doubly refracted. (05 Aug 1998) |