Involution

(redirected from involutional)
Also found in: Dictionary, Thesaurus, Medical, Legal.
Related to involutional: involutional depression, involutional psychosis, involutional ectropion, involutional ptosis

involution

[‚in·və′lü·shən]
(biology)
A turning or rolling in.
(embryology)
Gastrulation by ingrowth of blastomeres around the dorsal lip.
(mathematics)
Any transformation that is its own inverse.
In particular, a correspondence between the points on a line that is its own inverse, given algebraically by x ′ = (ax + b)/(cx-a), where a 2+ bc ≠ 0.
A correspondence between the lines passing through a given point on a plane such that corresponding lines pass through corresponding points of an involution of points on a line.
(medicine)
The retrogressive change to their normal condition that organs undergo after fulfilling their functional purposes, as the uterus after pregnancy.
The period of regression or the processes of decline or decay which occur in the human constitution after middle life.

Involution

 

(raising to a power), an algebraic operation consisting in repeating a quantity a n number of times:

The number a is the base of the power, n is the exponent, and an is the power. For example, 3x3x3x3 = 34 = 81. The second power of a number is called its square and the third power, its cube.


Involution

 

(regression), in biology, a reduction or loss, in the process of evolution, of certain organs, and a simplification of their organization and functions (for example, various degrees of intestinal reduction in certain parasitic worms and arthropods). Degenerative changes in protozoans and bacteria caused by unfavorable conditions in the habitat are also called involutional. In medicine, the term sometimes refers to atrophy of organs and tissues, such as in aging.

References in periodicals archive ?
The cervical and uterine involutional changes and any abnormal discharges observed on days 7, 14, 21, 28, 35 and 42 post-partum are presented in Table 3.
In acupuncture-related lipoatrophy there is an involutional pattern with thin and elongated fat lobules.
A unitary model for involutional osteoporosis: estrogen deficiency causes both type I and type II osteoporosis in postmenopausal women and contributes to bone loss in aging men.
Vitamin D and vitamin D analogues for preventing fractures associated with involutional and post-menopausal osteoporosis Cochrane Database Syst Rev 2005;20;(3):CD000227.
And yet L'Arcadia in Brenta is far from the stylistic influence of academic cenacles, and immersed in the involutional process of the late-seventeenth-century Italian novella.