growth retardation

growth retardation,

failure of an individual to develop at a normal rate of height and weight for his or her age. See also intrauterine growth retardation.

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growth

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.

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growth arrest line

a radiologically detectable line parallel to the growth plate in the metaphysis that indicates a temporary cessation of bone growth.

growth check

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.

compensatory growth

increased growth rate during a time period as a result of lower than normal growth rate during a previous period.

growth cone

bulbous enlargement at the tip of every growing axonal fiber in the fetus, from which many long filapodia extend.

growth curve

the curve obtained by plotting increase in size or numbers against the elapsed time.

growth disorders

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.

growth factor

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.

growth plate

the epiphyseal cartilage at which new bone formation occurs to lengthen long bones during their growth phase. Called also physis. See also epiphyseal plate.

growth promotants

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.

growth rate

rate of increase in body weight per unit of time, e.g. lb/day in beef cattle.

recombinant growth factor

recombinant growth hormone.

growth retardation

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.