| rate, respiratory | The number of breaths per minute (or, more formally, the number of movements indicative of inspiration and expiration per unit time). In practice, the respiratory rate is usually determined by counting the number of times the chest rises (or falls) per minute. By whatever means, the aim is to determine if the respirations are normal, abnormally fast (tachypnea), abnormally slow (technically termed bradypnea), or nonexistent (apnea). (12 Dec 1998) |
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| rate, sed | A sedimentation rate, or sed rate , is a blood test that detects and is used to monitor inflammation activity. It is measured by recording the rate at which red blood cells (rbcs) sediment in a tube over time. It increases (the rbcs sediment faster) with more inflammation. (12 Dec 1998) |
| rate, sedimentation | A sedimentation rate, or sed rate , is a blood test that detects and is used to monitor inflammation activity. It is measured by recording the rate at which red blood cells (rbcs) sediment in a tube over time. It increases (the rbcs sediment faster) with more inflammation. (12 Dec 1998) |
| rate-limiting step | <biochemistry> The slowest step in a metabolic pathway, or the step in an enzymatic reaction that requires the greatest amount of energy to initiate. (17 Dec 1997) |
| ratel | <zoology> Any carnivore of the genus Mellivora, allied to the weasels and the skunks. Synonym: honey badger. Several species are known in Africa and India. The Cape ratel (M. Capensis) and the Indian ratel (M. Indica) are the best known. The back is gray; the lower parts, face, and tail are black. They are fond of honey, and rob the nests of wild bees. Origin: F. Source: Websters Dictionary (01 Mar 1998) |
| ratfish | <zoology> Same as Rat-tail. Source: Websters Dictionary (01 Mar 1998) |
| Rathke's bundles | Muscular bundles on the lining walls of the ventricles of the heart. Synonym: columnae carneae, Rathke's bundles. (05 Mar 2000) |
| Rathke's cleft cyst | An intrasellar or suprasellar cyst lined by cuboidal epithelium derived from remnants of Rathke's pouch. (05 Mar 2000) |
| Rathke's diverticulum | A tubular outgrowth of ectoderm from the stomodeum of the embryo; it grows dorsad toward the infundibular process of the diencephalon, around which it forms a cup-like mass, giving rise to the pars distalis and pars juxtaneuralis of the hypophysis. Synonym: craniopharyngeal canal, hypophyseal pouch, Rathke's diverticulum, Rathke's pocket, Rathke's pouch. (05 Mar 2000) |
| Rathke's pouch | A tubular outgrowth of ectoderm from the stomodeum of the embryo; it grows dorsad toward the infundibular process of the diencephalon, around which it forms a cup-like mass, giving rise to the pars distalis and pars juxtaneuralis of the hypophysis. Synonym: craniopharyngeal canal, hypophyseal pouch, Rathke's diverticulum, Rathke's pocket, Rathke's pouch. (05 Mar 2000) |
| Rathke's pouch tumour | <oncology, tumour> A form of primary brain tumour which develops in the pituitary gland. These tumours often secrete increased quantities of pituitary hormones (for example growth hormone) which can result in conditions such as gigantism and acromegaly. They are often benign and rare and comprise less than 5% of childhood brain tumours. Other symptoms include vision changes, headache and weight gain. Treatment often includes a combination of surgery and radiation therapy. (27 Sep 1997) |
| Rathke, Martin | <person> German anatomist, physiologist, and pathologist, 1793-1860. See: Rathke's bundles, Rathke's cleft cyst, Rathke's diverticulum, Rathke's pocket, Rathke's pouch, Rathke's pouch tumour. (05 Mar 2000) |
| Rathke, Martin Heinrich | <person> Was a Physiologist and Pathologist. Appointed Professor at Dorpat and later at Konigsberg, where he was Professor of Zoology and Anatomy. Rathke's Pouch, Pocket - a depression in the roof of the embryonic mouth in front of the bucco-pharyngeal membrane. Lived: 1793-1860. B. Danzig, Aug 25th, 1793, d. Konigsberg, Sep 3rd, 1860. (05 Dec 1998) |
| rathripe | Rareripe, or early ripe. A rareripe. "Such who delight in rathripe fruits." (Fuller) Source: Websters Dictionary (01 Mar 1998) |
| ratify | To approve and sanction; to make valid; to establish; to settle; especially, to give sanction to, as something done by an agent or servant; as, to ratify an agreement, treaty, or contract; to ratify a nomination. "It is impossible for the divine power to set a seal to a lie by ratifying an imposture with such a miracle." (South) Origin: F. Ratifier, fr. L. Ratus fixed by calculation, firm, valid + -ficare (in comp) to make. See Rate, and -fy. Source: Websters Dictionary (01 Mar 1998) |