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a line that is not straight, or that describes part of a circle, especially a line representing varying values in a graph.
dose-effect curve (dose-response curve) a graphic representation of the effect caused by an agent (such as a drug or radiation) plotted against the dose, showing the relationship of the effect to changes in the dose.
growth curve the curve obtained by plotting increase in size or numbers against the elapsed time.
oxyhemoglobin dissociation curve a graphic curve representing the normal variation in the amount of oxygen that combines with hemoglobin as a function of the partial pressures of oxygen and carbon dioxide. The curve is said to shift to the right when less than a normal amount of oxygen is taken up by the blood at a given Po2, and to shift to the left when more than a normal amount is taken up. Factors influencing the shape of the curve include changes in the blood pH, Pco2, and temperature; the presence of carbon monoxide; alterations in the constituents of the erythrocytes; and certain disease states.
pulse curve sphygmogram.
Spee curve (curve of Spee) the anatomic curvature of the occlusal alignment of teeth, beginning at the tip of the lower canine, following the buccal cusps of the premolars and molars, and continuing to the anterior border of the ramus.
strength-duration curve a graphic representation of the relationship between the intensity of an electric stimulus at the motor point of a muscle and the length of time it must flow to elicit a minimal contraction; see also chronaxie and rheobase. In cardiac pacing it is useful in determining characteristics of a particular pacing electrode and determining the most efficient selection of pacing parameters for an appropriate safety margin.
survival curve a graph of the probability of survival versus time, commonly used to present the results of clinical trials, e.g., a graph of the fraction of patients surviving (until death, relapse, or some other defined endpoint) at each time after a certain therapeutic procedure.
a graphic representation of the change in size of an individual or a population over a period of time.
a graphic display of data showing proliferation of cell numbers in a culture as a function of time.
growth curvethe graphic representation of the growth of a population, which could be exponential where (theoretically) the density would eventually be increasing at an infinite rate, or could be logistic (see LOGISTIC CURVE where the density would stabilize near the CARRYING CAPACITY of the population. See Fig. 181 . Populations of microorganisms tend to go through a classic four-stage growth curve (see Fig. 182 ). The ‘lag’ phase is a time of adaptation to the new environment where such processes as ENZYME INDUCTION take place and reproduction rate equals death rate. The ‘log’ phase is a period of exponential growth (reproduction rate much greater than death rate). The ‘stationary’ phase is a time of equilibrium, representing the response to a limiting factor such as nutrient source, while little or no reproduction occurs during the ‘death’ phase, so the population declines.
growth curvea graph of change-in-height against age, which shows the greatest rate of change in infancy, flattening off until the growth spurt which on average reaches a peak at about age 12 in girls and 14 in boys.
1. the progressive increase in size of a living thing, especially the process by which the body reaches its point of complete physical development.
2. an abnormal formation of tissue, such as a tumor.
growth arrest line
a radiologically detectable line parallel to the growth plate in the metaphysis that indicates a temporary cessation of bone growth.
an event or state, usually the result of inadequate nutrition, parasitism or other disease, which temporarily reduces or stops growth in a young animal. Often followed by a period of compensatory growth.
increased growth rate during a time period as a result of lower than normal growth rate during a previous period.
bulbous enlargement at the tip of every growing axonal fiber in the fetus, from which many long filapodia extend.
the curve obtained by plotting increase in size or numbers against the elapsed time.
are sometimes traceable to excess or shortage of pituitary secretions, and may arise from hereditary defects or from glandular abnormalities. Abnormally large secretions of growth hormone can produce gigantism. Failure of the pituitary gland to develop sufficiently or to secrete adequate amounts of growth hormone may result in dwarfism. In adulthood, overproduction of growth hormone may lead to acromegaly.
substances which act as local regulators of cell division and function; classified as autocrine (act on cells of the same class) or paracrine (act on cells of a different class).
hematopoietic growth factors
see colony-stimulating factors.
one-step growth curve
a plot typical of the rapid growth of a virus in cell culture when all cells are infected simultaneously.
the epiphyseal cartilage at which new bone formation occurs to lengthen long bones during their growth phase. Called also physis. See also epiphyseal plate.
includes all agents used to increase the rate of body weight gain. Used principally in food animals but also in horses with a view to increasing muscle mass and physical performance, and in any species to hasten recuperation in animals debilitated by illness. Pharmaceutical preparations are principally anabolic steroids. Husbandry procedures include estrogen and zearalenone implants and dietary supplementation with antibiotics, monensin and, in the case of pigs, copper.
rate of increase in body weight per unit of time, e.g. lb/day in beef cattle.
recombinant growth factor
recombinant growth hormone.
stature smaller than normal; called also runt.
growth retardation lattice
radiodense metaphyseal lines parallel to the epiphyseal plate developing in fetal bone.
transforming growth factor [beta]
a family of extracellular signaling molecules important in the transformation of cells and in growth and development.