| PI | first meiotic prophase; isoelectric point; pacing impulse; package insert; pancreatic insufficiency;... |
|---|---|
| PMO | postmenopausal osteoporosis; Principal Medical Officer |
| PND | paroxysmal nocturnal dyspnea; partial neck dissection; postnasal drainage; postnasal drip; postnatal... |
| PNO | Principal Nursing Officer |
| POMP | phase-offset multiplanar [pulse sequence in magnetic resonance imaging]; principal outer material pr... |
| principal optic axis | A line passing through the centre of the lens of a refracting system at right angles to its surface. (05 Mar 2000) |
|---|---|
| principal plane | <microscopy> A plane normal to the principal axis of a lens, passing through a principal point. In geometrical construction of ray diagrams through a perfect lens, the single plane that can be considered (disregarding the refraction of the rays at each optical interface) to convert paraxial rays into rays converging onto the rear focal point. For thin symmetrical lenses, there is one principal plane that bisects the lens. For thick or complex lenses, there is a principal plane for the paraxial ray to the left, and another for the paraxial ray to the right, of the lens. (05 Aug 1998) |
| principal point | <microscopy> Mutually conjugate points lying on the lens axis and producing a magnification of one. Object and image distance as well as focal length are calculated (measured) from these points. (05 Aug 1998) |
| principal sensory nucleus of the trigeminus | <anatomy, nerve> The term commonly used to designate the nucleus pontis nervi trigeminalis; located in pons lateral to the motor trigeminal nucleus; receives primary sensory (touch and pressure) input via the trigeminal nerve, projects to ventral posteromedial nucleus of thalamus. Synonym: nucleus sensorius principalis nervi trigemini, nucleus sensorius superior nervi trigemini, principal sensory nucleus of the trigeminus. (05 Mar 2000) |
| principal sensory nucleus of trigeminal nerve | <anatomy, nerve> The term commonly used to designate the nucleus pontis nervi trigeminalis; located in pons lateral to the motor trigeminal nucleus; receives primary sensory (touch and pressure) input via the trigeminal nerve, projects to ventral posteromedial nucleus of thalamus. Synonym: nucleus sensorius principalis nervi trigemini, nucleus sensorius superior nervi trigemini, principal sensory nucleus of the trigeminus. (05 Mar 2000) |
| focus, principal | <physics> The point at which a lens focuses an axial object point. Synonymous with focal point. (05 Aug 1998) |
| A layer | <molecular biology> Right handed double helical DNA with approximately 11 residues per turn. Planes of base pairs in the helix are tilted 20 deg away from perpendicular to the axis of the helix. Formed from B DNA by dehydration. (18 Nov 1997) |
| ameloblastic layer | The internal layer of the enamel organ. Synonym: enamel layer. (05 Mar 2000) |
| anterior elastic layer | A transparent homogeneous acellular layer, 6 to 9 um thick, lying between the basal lamina of the outer layer of stratified epithelium and the substantia propria of the cornea; considered to be a basement membrane. Synonym: lamina limitans anterior corneae, anterior elastic layer, Bowman's membrane, lamina elastica anterior, limiting layers of cornea. (05 Mar 2000) |
| anterior layer of rectus abdominis sheath | The portion of the rectus sheath that lies anterior to the muscle, consisting in its upper two-thirds of contributions from the aponeuroses of the external and internal oblique muscles, and in its lower third (below the arcuralt line) of contributions from the aponeuroses of all three muscles of the anterolateral abdominal wall. Synonym: lamina anterior vaginae musculi recti abdominis. (05 Mar 2000) |
| anterior limiting layer of cornea | A transparent homogeneous acellular layer, 6 to 9 um thick, lying between the basal lamina of the outer layer of stratified epithelium and the substantia propria of the cornea; considered to be a basement membrane. Synonym: lamina limitans anterior corneae, anterior elastic layer, Bowman's membrane, lamina elastica anterior, limiting layers of cornea. (05 Mar 2000) |
| bacillary layer | The layer of the retina next to the pigment layer and containing the visual receptors. See: retina, granular layers of retina, neuroepithelial layer of retina. Synonym: bacillary layer. (05 Mar 2000) |
| basal cell layer | The deepest layer of the epidermis, composed of dividing stem cells and anchoring cells. Synonym: basal cell layer, columnar layer, germinative layer, palisade layer, stratum basale, stratum cylindricum, stratum germinativum. (05 Mar 2000) |
| basal layer | The outermost layer of the endometrium which undergoes only minimal changes during the menstrual cycle. Synonym: basal layer. Synonym: stratum basale epidermidis. (05 Mar 2000) |
| basal layer of choroid | The transparent, nearly structureless inner layer of the choroid in contact with the pigmented layer of the retina. Synonym: basal lamina of choroid, basal layer of choroid, Bruch's membrane, Henle's membrane, lamina vitrea, vitreous lamella, vitreous membrane. (05 Mar 2000) |