What is the definition of the term estrous cycle?
Freebase(0.00 / 0 votes)Rate this definition: The estrous cycle comprises the recurring physiologic changes that are induced by reproductive hormones in most mammalian therian females. Estrous cycles start after puberty in sexually mature females and are interrupted by anestrous phases or pregnancies. Typically, estrous cycles continue until death.
What is the meaning of Estral cycle?
: the correlated phenomena of the endocrine and reproductive systems of a female mammal from the beginning of one period of estrus to the beginning of the next — called also estral cycle, estrus cycle — called also estral cycle, estrus cycle
What are the 4 stages of the estrous cycle?
The estrous cycle is generally divided into the four stages of proestrus, estrus, metestrus, and diestrus. On cytological evaluation, these stages are defined by the absence, presence, or proportion of 4 basic cell types as well as by the cell density and arrangement of the cells on the slide.
What is the difference between menstrual cycle and estrous cycle in animals?
Animals that have menstrual cycles shed the endometrium through menstruation instead. Another difference is sexual activity. In species with estrous cycles, females are generally only sexually active during the estrus (oestrus) phase of their cycle (see below for the estrous cycle phases).
What is meant by estrous cycle?
The estrous cycle is defined as the period from one ovulation to a subsequent ovulation, with each ovulation being accompanied by signs of estrus and plasma progesterone concentrations less than 1 ng/ml.
What is the meaning of estrous?
Definition of estrus : a regularly recurrent state of sexual receptivity during which the female of most mammals will accept the male and is capable of conceiving : heat Some mares will exhibit estrus for 15 to 20 days.— Frederick Harper also : a single occurrence of this state.
Why is it called estrus cycle?
Estrus or oestrus refers to the phase when the female is sexually receptive ("in heat"). Under regulation by gonadotropic hormones, ovarian follicles mature and estrogen secretions exert their biggest influence.
What is heat or estrous cycle?
Dogs will have their first estrous (reproductive or heat) cycle when they reach puberty. Each cycle consists of several stages; the stage called estrus refers to when the female can become pregnant. Often a dog that is in the estrus stage is said to be in heat or in season.
What is heat period in a woman?
Estrus, or “heat,” typically coincides with ovulation, and during this time the female is receptive to the male. Estrus is preceded by proestrus, during which ovarian follicles mature under the influence of a follicle-stimulating hormone from the anterior pituitary.
What is estrus vs estrous?
Estrus is commonly called “heat.” Estrous is an adjective used to describe things related to estrus, such as the behaviors associated with estrus (estrous behaviors) or the period from one estrus to the next (estrous cycle).
Can males go into heat?
No. First off, males continuously produce sperm and, therefore, are always sexually receptive, so they do not go into heat. Females, however, do go... See full answer below.
What are the three types of estrous cycles?
The estrous cycle has four phases, namely proestrus, estrus, metestrus and diestrus and lasts for 4 to 5 days [4] (Table 1).
Can females be in heat?
Females of most vertebrate species exhibit recurring periods of heightened sexual activity in which they are sexually attractive, proceptive and receptive to males. In mammalian females (except Old World monkeys, apes and humans), this periodic sex appeal is referred to as 'heat' or 'estrus'.
What is the estrous cycle?
The estrous cycle (derived from Latin oestrus; "frenzy", originally from Greek οἶστρος, oîstros; "gadfly") is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females.
When do estrous cycles start?
Estrous cycles start after sexual maturity in females and are interrupted by anestrous phases, otherwise known as "rest" phases, or by pregnancies. Typically, estrous cycles repeat until death. These cycles are widely variable in duration and frequency depending on the species.
What is the difference between oestrous and menstrual cycles?
One difference is that animals that have oestrous cycles resorb the endometrium if conception does not occur during that cycle. Animals that have menstrual cycles shed the endometrium through menstruation instead. Another difference is sexual activity.
How long is the oestrous cycle of buffalo?
Buffalo have an oestrous cycle of about 22 to 24 days. Buffalo are known for difficult eostrus detection. This is one major reason for being less productive than cattle. During four phases of its oestrous cycle, mean weight of corpus luteum has been found to be 1.23±0.22g (metoestrus), 3.15±0.10g (early dioestrus), 2.25±0.32g (late dioestrus), and 1.89±0.31g (pro-oestrus/oestrus), respectively. The plasma progesterone concentration was 1.68±0.37, 4.29±0.22, 3.89±0.33, and 0.34±0.14 ng/ml while mean vascular density (mean number of vessels/10 microscopic fields at 400x) in corpus luteum was 6.33±0.99, 18.00±0.86, 11.50±0.76, and 2.83±0.60 during the metestrus, early diestrus, late diestrus and proestrus/estrus, respectively.
What is the spelling of "estrus"?
In British and most Commonwealth English, the spelling is oestrus or (rarely) œstrus. In all English spellings, the noun ends in -us and the adjective in -ous. Thus in North American English, a mammal may be described as "in estrus" when it is in that particular part of the estrous cycle .
How long does a cat's oestrous cycle last?
Even within species significant variability can be observed, thus cats may undergo an oestrous cycle of 3 to 7 weeks. Domestication can affect oestrous cycles due to changes in the environment. For most species, vaginal smear cytology may be used in order to identify oestrous cycle phases and durations.
What is the term for the regression of the corpus luteum?
In the absence of pregnancy the diestrus phase (also termed pseudo-pregnancy) terminates with the regression of the corpus luteum. The lining in the uterus is not shed, but is reorganized for the next cycle. Other spellings include metoestrus, metestrum, metoestrum, dioestrus, diestrum, and dioestrum .
How long does a reproductive cycle last?
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.
What is the Krebs cycle?
Krebs cycle tricarboxylic acid cycle. 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 ...
What is the estrous cycle?
estrous cycle. The series of changes that occur in the female of most mammals from one period of estrus to another. The estrous cycle usually takes place during the period known as the breeding season, which ensures that young are born at a time when the chance of survival is greatest. The length of the cycle varies from species to species.
How to use the estrous cycle in a sentence?
How to use estrous cycle in a sentence. It almost mirrors the Buddhist cycle of life, death, and rebirth. Eventually, the mistletoe bush grows, blooms, and forms berries, and the cycle begins anew. The Newsroom aired its final episode on Sunday, already an eternity ago in news-cycle terms.
Are we missing a good definition for estrous cycle? Don't keep it to yourself..
The ASL fingerspelling provided here is most commonly used for proper names of people and places; it is also used in some languages for concepts for which no sign is available at that moment.
Definitions & Translations
Get instant definitions for any word that hits you anywhere on the web!
When does the estrous cycle stop?
The estrous cycle stops during lactation except for one oestrus 12-20 hours postpartum. The information below refers to determining the stage of the estrous cycle in the mouse by the appearance of the vagina. Estrous Diestrus - Vagina has a small opening and the tissues are bluish-purple in color and very moist.
How many stages are there in the estrous cycle?
The estrous cycle is generally divided into the four stages of proestrus, estrus, metestrus, and diestrus. On cytological evaluation, these stages are defined by the absence, presence, or proportion of 4 basic cell types as well as by the cell density and arrangement of the cells on the slide. Multiple references regarding the cytology ...
What is the term for animals that have multiple estrous cycles?
Also do not confuse with "estrus", which is a phase of the cycle. There are also a variety of different forms: Polyestrous Animals - Estrous cycles throughout the year ( cattle, pigs, mice, rats ). Seasonally Polyestrous Animals - Animals that have multiple estrous cycles only during certain periods of the year (horses, sheep, goats, deer, cats ).
What is the main reproductive cycle of other species females of non-primate vertebrates?
Introduction. The estrous cycle (British spelling, oestrous) is the main reproductive cycle of other species females of non-primate vertebrates, for example rats, mice, horses, pig have this form of reproductive cycle. Also do not confuse with "estrus", which is a phase of the cycle. There are also a variety of different forms:
Which receptors regulate estrous cycle?
Bradykinin during estrous cycle of mouse "Thus, this study indicates that the levels of bradykinin and bradykinin B (2)-receptor both simultaneously regulate estrous cycle and are important components for the reproductive process.".
How long does it take for a uterine ovaries to stop sucking?
The feedback systems between the ovaries, uterus, hypothalamus and pituitary gland govern a cycle of events that takes 18-21 days. If conception occurs this cyclic pattern is interrupted and pregnancy is maintained for approximately 114 days. Removal of the sucking stimulus at weaning triggers a new sequence of events.
Where did the word "oestrum" come from?
This word seems to offer more difficulties as to pronunciation and spelling than any other technical word in biology. Derived originally from the Greek oloxpos, signifying the gadfly, and taken over into Latin as oestrus, the word came secondarily to mean frenzy or strong desire. The Latin derivative is properly of masculine gender, following the Greek, but we are told by Tyson that some grammarians gave it the neuter form oestrum as early as 400 a.v. In its more general senses the word became naturalized in English with the spelling oestrum and has been so used in prose and poetic literature by many writers (see Tyson’s article and the Oxford English Dictionary).
estrous cycle in American English
Webster’s New World College Dictionary, 4th Edition. Copyright © 2010 by Houghton Mifflin Harcourt. All rights reserved.
estrous cycle in American English
Most material © 2005, 1997, 1991 by Penguin Random House LLC. Modified entries © 2019 by Penguin Random House LLC and HarperCollins Publishers Ltd
Overview
Etymology and nomenclature
Estrus is derived via Latin oestrus ('frenzy', 'gadfly'), from Greek οἶστρος oîstros (literally 'gadfly', more figuratively 'frenzy', 'madness', among other meanings like 'breeze'). Specifically, this refers to the gadfly in Ancient Greek mythology that Hera sent to torment Io, who had been won in her heifer form by Zeus. Euripides used oestrus to indicate 'frenzy', and to describe madness. Homer used the word to describe panic. Plato also used it to refer to an irrational drive and to describe the soul "dri…
Differences from the menstrual cycle
Mammals share the same reproductive system, including the regulatory hypothalamic system that produces gonadotropin-releasing hormone in pulses, the pituitary gland that secretes follicle-stimulating hormone and luteinizing hormone, and the ovary itself that releases sex hormones, including estrogens and progesterone.
However, species vary significantly in the detailed functioning. One difference is that animals th…
Four phases
A four-phase terminology is used in reference to animals with estrous cycles.
One or several follicles of the ovary start to grow. Their number is species-specific. Typically this phase can last as little as one day or as long as three weeks, depending on the species. Under the influence of estrogen, the lining of the uterus (endometrium) starts to develop. Some animals may experience vaginal secretions that could be bloody. The female is not yet sexually receptive…
Cycle variability
Estrous cycle variability differs among species, but cycles are typically more frequent in smaller animals. Even within species significant variability can be observed, thus cats may undergo an estrous cycle of 3 to 7 weeks. Domestication can affect estrous cycles due to changes in the environment. For most species, vaginal smear cytology may be used in order to identify estrous cycle phases and durations.
Frequency
Some species, such as cats, cows and domestic pigs, are polyestrous, meaning that they can go into heat several times per year. Seasonally polyestrous animals or seasonal breeders have more than one estrous cycle during a specific time of the year and can be divided into short-day and long-day breeders:
• Short-day breeders, such as sheep, goats, deer and elk are sexually active in fall or winter.
Specific species
The female cat in heat has an estrus of 14 to 21 days and is generally characterized as an induced ovulator, since coitus induces ovulation. However, various incidents of spontaneous ovulation have been documented in the domestic cat and various non-domestic species. Without ovulation, she may enter interestrus, which is the combined stages of diestrus and anestrus, before reentering estrus. With the induction of ovulation, the female becomes pregnant or undergoes a …
See also
• Mating system
• Musth
• Neutering
• Progesterone-releasing intravaginal device
• Reproductive cycle