| ejection fraction | <cardiology> A measure of ventricular contractility, equal to normally 65 |
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| milk ejection | Reflex in which tactile stimulation of nipples causes release of oxytocin which causes myoepithelial cells surrounding mammary alveoli to contract and expel the milk. Applies to humans and animals. (12 Dec 1998) |
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| milk-ejection reflex | Release of milk from the breast following tactile stimulation of the nipple; the afferent path is postulated to exist from the nipple to the hypothalamus; the efferent limb is represented by the neurohypophysial release of oxytocin into the systemic circulation; contraction of myoepithelial elements within the breast, caused by oxytocin, moves milk into the collecting ducts and toward the nipple. Synonym: let-down reflex, milk let-down reflex. (05 Mar 2000) |
| ejection | 1. The act of ejecting or casting out; discharge; expulsion; evacuation. "Vast ejection of ashes." . "The ejection of a word." 2. <physiology> The act or process of discharging anything from the body, particularly the excretions. 3. The state of being ejected or cast out; dispossession; banishment. Origin: L. Ejectio: cf. F. Ejection. Source: Websters Dictionary (01 Mar 1998) |
| ejection murmur | A diamond-shaped systolic murmur produced by the ejection of blood into the aorta or pulmonary artery and ending by the time of the second heart sound component produced, respectively, by closing of the aortic or pulmonic valve. (05 Mar 2000) |
| ejection period | The period in the cardiac cycle when the semilunar valves are open and blood is being ejected from the ventricles into the arterial system. Synonym: ejection period. (05 Mar 2000) |
| ejection sounds | Click-like sounds during ejection from a hypertensive aorta or pulmonary artery or associated with stenosis (particularly congenital) of the aortic or pulmonic valve. (05 Mar 2000) |
| left ventricular ejection time | The time measured clinically from onset to incisural notch of the carotid or other pulse; properly the time of ejection of blood from the left ventricle beginning with aortic valve opening and ending with aortic valve closure. (05 Mar 2000) |
| aetiological fraction | <epidemiology> The reduction in disease when a risk factor is removed. If I* is the number of people that a risk factor is responsible for and I is the total number of cases over the same period, then the aetiological fraction is I*/I. Equivalently, the aetiological fraction is (I-Io)/I. Where Io is the number of cases in the absence of the risk factor. Also known as the attributable fraction. (05 Dec 1998) |
| amorphous fraction of adrenal cortex | Noncrystalline residue of an acetone extract of the adrenal cortex after crystalline steroids, e.g., corticosterone, deoxycorticosterone, etc., have been isolated. (05 Mar 2000) |
| attributable fraction | <epidemiology> The same as aetiological fraction. (05 Dec 1998) |
| recombination fraction | The proportion of progeny of a mating pair of specific genotype and coupling phase that are recombinant; there must be no differential selection among the possible types of progeny, and the recombination fraction should be the same regardless of the alleles involved or their coupling phase. (05 Mar 2000) |
| regurgitant fraction | The amount of blood regurgitated into a cardiac chamber divided by the stroke output; normally, no blood regurgitates; in patients with severe valvular lesions such as mitral or aortic insufficiency, regurgitation can approach 80%; this fraction affords a quantitative measure of the severity of the valvular lesion. (05 Mar 2000) |
| microsomal fraction | Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (glick, glossary of biochemistry and molecular biology, 1990; from rieger et al., glossary of genetics: classical and molecular, 5th ed) (12 Dec 1998) |
| mole fraction | The ratio of the moles of one component of a system to the total moles of all the components present. (05 Mar 2000) |
| human antihemophilic fraction | A lyophilised concentrate of factor VIII, obtained from fresh normal human plasma; used as a haemostatic agent in haemophilia. Synonym: antihemophilic globulin, human antihemophilic fraction. (05 Mar 2000) |