| PD | Doctor of Pharmacy; Dublin Pharmacopoeia; interpupillary distance; Paget disease; pancreatic duct; p... |
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| PICA | percutaneous transluminal coronary angioplasty; Porch Index of Communicative Abilities; posterior in... |
| PP | diphosphate group; emphysema [pink puffers]; near point of accommodation [Lat. punctum proximum]; pa... |
| PPA | palpation, percussion, auscultation; pepsin A; phenylpropanolamine; phenylpyruvic acid; Pittsburgh p... |
| Sp | the most posterior point on the posterior contour of the sella turcica; species; specific; specimen;... |
| cardiac segment | Cardiac segment; medial basal segment of inferior lobe of right and left lung; can only be seen from medial and inferior surfaces since it does not reach lateral surface of lung. Synonym: segmentum basale mediale, segmentum cardiacum, cardiac segment. (05 Mar 2000) |
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| valley segment | That portion of a stream network with similar morphologies and governing geomorphic processes identified by valley bottom and sideslope geomorphic characteristics. (05 Dec 1998) |
| Ranvier's segment | The portion of a myelinated nerve fibre between two successive nodes. Synonym: interannular segment, internode, Ranvier's segment, segmentum internodale. (05 Mar 2000) |
| medial basal segment | Cardiac segment; medial basal segment of inferior lobe of right and left lung; can only be seen from medial and inferior surfaces since it does not reach lateral surface of lung. Synonym: segmentum basale mediale, segmentum cardiacum, cardiac segment. (05 Mar 2000) |
| medial segment | A delimited part or section of an organ or other structure which lies closer or closest to the midline than the other similar parts or sections. 1) segmentum mediale (hepar); the medial segment of the left lobe of the liver. 2) segmentum mediale (pulmo dexter); [S 5]; the medial segment of the middle lobe of the right lung. Synonym: segmentum mediale. (05 Mar 2000) |
| cesarian section, lower segment | A Cesarian section in which the surgical incision (cut) is made in the lower segment of the uterus. (12 Dec 1998) |
| mesoblastic segment | 1. <zoology> One of the actual or ideal serial segments of which an animal, especially. An articulate or vertebrate, is is composed; somatome; metamere. Somitic. 2. <embryology> Segmentally arranged blocks of mesoderm lying on either side of the notochord and neural tube during development of the vertebrate embryo. Somites are formed sequentially, starting at the head. Each somite will give rise to muscle from the myotome region), spinal column (from the sclerotome) and dermis (from dermatome). (04 Mar 1998) |
| rod outer segment | <ophthalmology, physiology> Major photoreceptor cell of vertebrate retina (about 125 million in a human eye). Columnar cells (about 40m long, 1m diameter) having three distinct regions: a region adjacent to and synapsed with, the neural layer of the retina contains the nucleus and other cytoplasmic organelles, below this is the inner segment, rich in mitochondria, that is connected through a thin neck (in which is located a ciliary body) to the outer segment. The outer segment largely consists of a stack of discs membrane infoldings that are incompletely separated in cones) that are continually replenished near the inner segment and that are shed from the distal end and phagocytosed by the pigmented epithelium. The membranes of the discs are rich in rhodopsin, the pigment that absorbs light. (03 Jul 1999) |
| RST segment | The part of the electrocardiogram between the QRS complex and the T wave. Virtually never distinct in normal hearts in which it forms the initial limb of the T wave without an agreed endpoint. (05 Mar 2000) |
| P-R segment | That part of the electrocardiographic curve between the end of the P wave and the beginning of the QRS complex. (05 Mar 2000) |
| section, lower segment cesarian | A Cesarian section in which the surgical incision (cut) is made in the lower segment of the uterus. (12 Dec 1998) |
| segment | <biology> A portion of a larger body or structure, set off by natural or arbitrarily established boundaries. Origin: L. Segmentum = a piece cut off (18 Nov 1997) |
| segment long spacing | <biochemistry> Abnormal packing pattern of collagen molecules formed if ATP is added to acidic collagen solutions, in which lateral aggregates of molecules are produced. Each aggregate is 300 nm long and the molecules are all in register. If segment long spacing aggregates are overlapped with a quarter stagger, the 67 nm banding pattern of normal fibrils is reconstituted. Acronym: SLS (18 Nov 1997) |
| segment polarity gene | <molecular biology> A segmentation gene, responsible for specifying anterior posterior polarity within individual embryonic segments. In Drosophila, there are at least 10 such genes, for example gooseberry. (18 Nov 1997) |
| neural segment | Alternate swellings and constrictions seen along the neuraxis at early stages of neural tube development, thought to be evidence of intrinsic segmentation in the CNS. Neuromeres or segments in the hindbrain region are called rhombomeres and have been shown to be lineage restriction units, each constructing a defined piece of hindbrain. (18 Nov 1997) |