hair cycle


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Related to hair cycle: hair follicle, Telogen effluvium

cycle

 [si´k'l]
a succession or recurring series of events.
cardiac cycle a complete cardiac movement, or heart beat, including systole, diastole, and the intervening pause.
Cardiac cycle. From Applegate, 2000.
cell cycle the cycle of biochemical and morphological events occurring in a reproducing cell population; it consists of the S phase, occurring toward the end of interphase, in which DNA is synthesized; the G2 phase, a relatively quiescent period; the M phase, consisting of the four phases of mitosis; and the G1 phase of interphase, which lasts until the S phase of the next cycle.
citric acid cycle tricarboxylic acid cycle.
estrous cycle the recurring periods of estrus in adult females of most mammalian species and the correlated changes in the reproductive tract from one period to another.
hair cycle the successive phases of the production and then loss of hair, consisting of anagen, catagen, and telogen.
menstrual cycle see menstrual cycle.
ovarian cycle the sequence of physiologic changes in the ovary involved in ovulation; see also ovulation and reproduction.
reproductive cycle the cycle of physiologic changes in the reproductive organs, from the time of fertilization of the ovum through gestation and childbirth; see also reproduction.
sex cycle (sexual cycle)
1. the physiologic changes that recur regularly in the reproductive organs of nonpregnant female mammals.
2. the period of sexual reproduction in an organism that also reproduces asexually.
tricarboxylic acid cycle the cyclic metabolic mechanism by which the complete oxidation of the acetyl portion of acetyl-coenzyme A is effected; the process is the chief source of mammalian energy, during which carbon chains of sugars, fatty acids, and amino acids are metabolized to yield carbon dioxide, water, and high-energy phosphate bonds. Called also citric acid cycle, Krebs cycle, and TCA cycle.
 Central pathways of metabolism: How the body produces energy from the energy-containing nutrients using the tricarboxylic acid cycle. From Davis and Sherer, 1994.
urea cycle a cyclic series of reactions that produce urea; it is a major route for removal of the ammonia produced in the metabolism of amino acids in the liver and kidney.

hair cy·cle

the cyclic phases of growth (anagen), regression (catagen), and quiescence (telogen) in the life of a hair.

hair cycle

the successive phases of the production and then loss of hair, consisting of growth (anagen), regression (catagen), and quiescence (telogen).

hair cycle

The repetitive sequence of growth and rest affecting the production of the hair follicles. The growth phase is known as anagen and this varies in length in different sites. The scalp anagen may last for several years. The rest phase is called the telogen. After about three months of telogen the hair is shed and a new anagen starts. Between these is the brief catagen during which the base of the hair becomes club-shaped.
References in periodicals archive ?
Students will learn about the hair cycle and how to plot hair growth on a graph.
Control of the hair cycle and hair diseases as cycling disorders.
A sudden drop in calories can make the growing phase of the hair cycle stop too soon, which can lead to hair loss," warns Linda.
Furthermore it is well established that Dihydrotestostcrone (DHT) shortens hair cycle growth, causing follicle miniaturization and producing progressively shorter and finer hair.
Scientists hope that by studying the hair cycle they will learn to control the growth and regeneration of hair and skin, But whether the goal is to slow the balding process in men, increase wool production in sheep or stop skin cell proliferation in cancer patients, the key lies in understanding the molecular signals that regulate the cycle of growth and rest.
In this study, a small molecule Hedgehog agonist, when topically formulated and applied to the skin, triggers the transition of hair follicles from the resting to the growth phase of the hair cycle.
It has a direct action on DHT preventing the hair cycle to shorten and hair follicle miniaturization, improving the ECM proteins for better anchoring and promoting an increase of follicle size.
The results of the study show that a topically applied small molecule agonist of the Hedgehog signaling pathway can stimulate the transition of hair follicles from the resting to the growth stage of the hair cycle.
The hair cycle consists of three defined stages - growth, followed by regression and rest.
In the current study, the small molecule Hedgehog agonist, when topically formulated and applied to the skin, was able to transition the hair follicles from the resting phase of the hair cycle to the growth phase, resulting in pronounced stimulation of hair growth.