| Heuser's membrane | A layer of cells delaminated from the inner surface of the blastocystic cytotrophoblast and from the envelope of the primary yolk sac during the second week of embryonic life. Synonym: Heuser's membrane. (05 Mar 2000) |
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| secondary egg membrane | See: egg membrane. (05 Mar 2000) |
| secondary tympanic membrane | The membrane closing the fenestra cochleae or rotunda. Synonym: membrana tympani secundaria, Scarpa's membrane. (05 Mar 2000) |
| semipermeable membrane | <biology, physiology> A membrane that is selectively permeable to only one (or a few) solutes. The potential developed across a membrane permeable to only one ionic species is given by the Nernst equation for the species: this is the basis for the operation of ion selective electrodes. (18 Nov 1997) |
| pupillary membrane | Remnants of the central portion of the anterior layer of the iris stroma (the iridopupillary lamina) which occludes the pupil in foetal life, and normally atrophies about the seventh month of gestation. Persistent strands usually stretch across the pupil from one iris collarette to the other, without touching the pupillary margin. Failure to regress is a rare cause of congenital blindness. Synonym: membrana pupillaris, Wachendorf's membrane. (05 Mar 2000) |
| purple membrane | <cell biology> Plasma membrane of Halobacterium and Halococcus, that contains a protein bound carotenoid pigment that absorbs light and uses the energy to translocate protons from the cytoplasm to the exterior. The proton gradient then provides energy for ATP synthesis. The binding protein is called bacteriorhodopsin or purple membrane protein. (18 Nov 1997) |
| pyogenic membrane | A layer of pus cells lining an abscess cavity which have not yet autolyzed. Synonym: prophylactic membrane. (05 Mar 2000) |
| serous membrane | <anatomy, pathology> One of the delicate membranes of connective tissue which line the internal cavities of the body. Synonym: serosa. (28 May 1998) |
| Hunter's membrane | The mucous membrane of the pregnant uterus that has already undergone certain changes, under the influence of the ovulation cycle, to fit it for the implantation and nutrition of the ovum; so-called because the membrane is cast off after labour. Synonym: membrana decidua, caduca, decidua, Hunter's membrane. (05 Mar 2000) |
| Huxley's membrane | A layer of cells interposed between Henle's layer and the cuticle of the inner root sheath of the hair follicle. Synonym: Huxley's membrane, Huxley's sheath. (05 Mar 2000) |
| hyaline membrane | The thin, clear basement membrane beneath certain epithelia. Synonym: glassy membrane. (05 Mar 2000) |
| hyaline membrane disease | <disease> A respiratory disease of the newborn. Often associated with prematurity or maternal diabetes. This disorder is characterised by a lack of pulmonary surfactant, a substance which increases pulmonary compliance and prevents collapse of the pulmonary air sacs. (27 Sep 1997) |
| hyaline membrane disease of the newborn | A disease seen especially in premature neonates with respiratory distress; characterised postmortem by atelectasis and alveolar ducts lined by an eosinophilic membrane; also associated with reduced amounts of lung surfactant. Synonym: hyaline membrane syndrome, respiratory distress syndrome of the newborn. (05 Mar 2000) |
| hyaline membrane syndrome | A disease seen especially in premature neonates with respiratory distress; characterised postmortem by atelectasis and alveolar ducts lined by an eosinophilic membrane; also associated with reduced amounts of lung surfactant. Synonym: hyaline membrane syndrome, respiratory distress syndrome of the newborn. (05 Mar 2000) |
| hyaloid membrane | A transparent homogeneous acellular layer between the substantia propria and the endothelial layer of the cornea; considered to be a highly developed basement membrane. Synonym: lamina limitans posterior corneae, membrana vitrea, Descemet's membrane, Duddell's membrane, entocornea, hyaloid membrane, lamina elastica posterior, limiting layers of cornea, membrana hyaloidea, posterior elastic layer, tunica vitrea, vitreous membrane. (05 Mar 2000) |