| chorionic villus sampling | <procedure> A procedure for obtaining a sample of chorionic villi for the purpose of genetic testing, usually performed between 9 and 12th weeks of pregnancy. Amniocentesis testing has greatly supplanted the use of this form of genetic testing. (27 Sep 1997) |
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| hormone, human chorionic gonadotropin | A human hormone made by chorionic cells (in the foetal part of the placenta), hcg is directed at the gonads and stimulates them. Hcg becomes detectable (by immunologic means) within days of the time of fertilization. It therefore forms the foundation of most common pregnancy tests. The level of hcg in maternal serum enters as one component in the double and the triple screens used during pregnancy to assign risks of down syndrome and other foetal disorders. (12 Dec 1998) |
| human chorionic gonadotrophin | <hormone, tumour marker> A hormone that is produced by the developing placenta and by the fertilized egg after implantation in the uterine wall. This hormone is measured in the blood to determine pregnancy. Human chorionic gonadotrophin increases in quantity through the first trimester of pregnancy and begin to taper off after 85 days. Serum human chorionic gonadotrophin testing is accurate 48 hour post conception. Urine human chorionic gonadotrophin testing is a popular method of home pregnancy determination as human chorionic gonadotrophin can be detected in urine. Acronym: HCG (18 Nov 1997) |
| human chorionic gonadotropin | A human hormone made by chorionic cells (in the foetal part of the placenta), hcg is directed at the gonads and stimulates them. Hcg becomes detectable (by immunologic means) within days of fertilization and forms the foundation of the common pregnancy tests. The level of hcg in maternal serum also enters as one component in the double and the triple screens used during pregnancy to assign risks of down syndrome and other foetal disorders. (12 Dec 1998) |
| human chorionic somatomammotropic hormone | human placental lactogen |
| human chorionic somatomammotropin | human placental lactogen |
| abdominal sac | The part of the embryonic celom that becomes the abdominal cavity. (05 Mar 2000) |
| air sac | <zoology> Thin-walled sacs or spaces which function as a part of the respiratory system in birds, fishes, insects, and mammals. The sacs are filled with air and connected with the air passages of the lungs; an air cell. Source: Websters Dictionary (04 Jul 1999) |
| allantoic sac | The dilated distal portion of the allantois; it forms part of the placenta in many mammals. (05 Mar 2000) |
| alveolar sac | Terminal dilation of the alveolar ducts that give rise to alveoli in the lung; a small air chamber in the pulmonary tissue from which the pulmonary alveoli project like bays and into which an alveolar duct opens; in birds, air-containing extensions of bronchi that connect with bone cavities. Synonym: sacculus alveolaris, air sac. (05 Mar 2000) |
| amniotic sac | <anatomy, obstetrics> Sac, enclosing the embryo of amniote vertebrates, that provides a fluid environment to prevent dehydration during development of land based animals. See: amnion. (18 Nov 1997) |
| anal sac | A vesicular cutaneous invagination opening by a duct on each side of the anal canal in carnivores (best developed in skunks, but absent in some bears, the raccoon, kinkajou, coati, and sea otter), each lying between the external and internal anal sphincter muscles, which aid in emptying the contents. The sac stores odouriferous scent markers produced by glands that line its wall or duct; frequently the sac becomes impacted in the dog or cat, requiring manual emptying. (05 Mar 2000) |
| aneurysmal sac | The dilated wall of an artery in a saccular aneurysm. (05 Mar 2000) |
| aortic sac | In mammalian embryos, the endothelially lined dilation just distal to the truncus arteriosus; it is the primordial vascular channel from which the aortic arches arise and is homologous to the ventral aorta of gill-bearing vertebrates. (05 Mar 2000) |
| rami laterales ramorum dorsalium nervorum cervicalium/thoracalium/lumbalium/sac | Lateral branch of dorsal primary rami of spinal nerves. See: lateral branches. (05 Mar 2000) |