estrous cycle


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Related to estrous cycle: anestrous

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.

es·trous cy·cle

the series of physiologic uterine, ovarian, and other changes that occur in higher animals, consisting of proestrus, estrus, postestrus, and anestrus or diestrus.

estrous cycle

n.
The recurrent set of physiological and behavioral changes that take place from one period of estrus to another.

es·trous cy·cle

(es'trŭs sī'kĕl)
The series of cyclic uterine, ovarian, and other changes that occur in higher animals.
Synonym(s): oestrous cycle.

oestrous cycle

or

estrous cycle

a reproductive cycle caused by the cyclic production of gonadotrophic hormones by the PITUITARY GLAND. It occurs in adult female mammals and is only complete when pregnancy does not occur. It lasts from 5 to 60 days, dependent on species.

Initially, follicle growth occurs in the ovary as a result of FOLLICLE-STIMULATING HORMONE being secreted by the anterior pituitary This results in increased OESTROGEN production and a thickening of the uterus lining. The build-up of oestrogen results in positive feed-back, causing the anterior pituitary to produce LUTEINIZING HORMONE which in turn brings about ovulation with the formation of a CORPUS LUTEUM, development of the uterine glands, secretion of PROGESTERONE by the corpus luteum (which inhibits FSH production) and a consequent decrease in oestrogen production. Fertilization may occur at this stage and if it does so, pregnancy results. If not, there is a regression of the corpus luteum and a feedback to the anterior pituitary to produce FSH as progesterone decreases. New follicles are formed, the lining of the uterus thins, menstruation (see MENSTRUAL CYCLE occurs in human females and some other primates, and there is a cessation of progesterone secretion and a continued decrease of oestrogen. The cycle then begins again as new follicles grow. Only during the initial period of the cycle, during which ovulation takes place, will the female of most mammalian species copulate (the period of ‘heat'or oestrus).

References in periodicals archive ?
Estrous cycles. For 19 days beginning on PND46 or PND47, daily vaginal smears of A-females were examined microscopically for vaginal cytology.
It may be one of the mechanisms responsible for local orchestrating events in endometrial tissue during estrous cycle and implantation.
Estrous cycle and sex as regulating factors of baseline brain oxidative metabolism and behavior.
Colony size reduction and increase of embryo yield when using the L rat strain for bioengineering projects can be achieved through methods other than the AIUI technique, such as superovulation or estrous cycle synchronization.
Murphy, "Variations in parametrial white adipose tissue mass during the mouse estrous cycle: relationship with the expression of peroxisome proliferator-activated receptor-y and retinoic acid receptor-a," Canadian Journal of Physiology and Pharmacology, vol.
Serum level of sex hormones and corticosterone throughout 4 and 5 days estrous cycles in Fischer 344 rats and their stimulation in ovariectomized females.
Stages of estrous cycle were determined by cellular morphology and ratio of epithelial cells to leukocytes in each slide.
The most important characteristics of FSH patterns during the estrous cycle include the following:
Estrous cycle (ehs-truhs) The pattern of hormonal and behavioral characteristics that mark the reproductive status of females (see Figure 3-7).
* Describe reproductive hormones during the estrous cycle