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Estrous
The estrous cycle (, originally ) is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females. 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.Bronson, F. H., 1989. Mammalian Reproductive Biology. University of Chicago Press, Chicago, IL, USA. Some animals may display bloody vaginal discharge, often mistaken for menstruation. Many mammals used in commercial agriculture, such as cattle and sheep, may have their estrous cycles artificially controlled with hormonal medications for optimum productivity. The male equivalent, seen primarily in ruminants, is called rut. Differences from the menstrual cycle Mammals share the same reproductive system, including the regulatory hypothalamic system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estrus
The estrous cycle (, originally ) is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females. 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.Bronson, F. H., 1989. Mammalian Reproductive Biology. University of Chicago Press, Chicago, IL, USA. Some animals may display bloody vaginal discharge, often mistaken for menstruation. Many mammals used in commercial agriculture, such as cattle and sheep, may have their estrous cycles artificially controlled with hormonal medications for optimum productivity. The male equivalent, seen primarily in ruminants, is called rut. Differences from the menstrual cycle Mammals share the same reproductive system, including the regulatory hypothalamic syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Menstruation (mammal)
Menstruation is the shedding of the uterine lining ( endometrium). It occurs on a regular basis in uninseminated sexually reproductive-age females of certain mammal species. Although there is some disagreement in definitions between sources, menstruation is generally considered to be limited to primates. Overt menstruation (where there is bleeding from the uterus through the vagina) is found primarily in humans and close relatives such as chimpanzees. It is common in simians (Old World monkeys, New World monkeys, and apes), but completely lacking in strepsirrhine primates and possibly weakly present in tarsiers. Beyond primates, it is known only in bats, the elephant shrew, and the spiny mouse species '' Acomys cahirinus''. Females of other species of placental mammal undergo estrous cycles, in which the endometrium is completely reabsorbed by the animal (covert menstruation) at the end of its reproductive cycle. Many zoologists regard this as different from a "true" menstr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endometrium
The endometrium is the inner epithelial layer, along with its mucous membrane, of the mammalian uterus. It has a basal layer and a functional layer: the basal layer contains stem cells which regenerate the functional layer. The functional layer thickens and then is shed during menstruation in humans and some other mammals, including apes, Old World monkeys, some species of bat, the elephant shrew and the Cairo spiny mouse. In most other mammals, the endometrium is reabsorbed in the estrous cycle. During pregnancy, the glands and blood vessels in the endometrium further increase in size and number. Vascular spaces fuse and become interconnected, forming the placenta, which supplies oxygen and nutrition to the embryo and fetus.Blue Histology - Female Reproductive System . School ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concealed Ovulation
Concealed ovulation or hidden œstrus in a species is the lack of any perceptible change in an adult female (for instance, a change in appearance or scent) when she is fertile and near ovulation. Some examples of perceptible changes are swelling and redness of the genitalia in baboons and bonobos, and pheromone release in the feline family. In contrast, the females of humans and a few other species that undergo hidden estrus have few external signs of fecundity, making it difficult for a mate to consciously deduce, by means of external signs only, whether or not a female is near ovulation. Human females In humans, an adult woman's fertility peaks for a few days during each roughly monthly cycle. The frequency and length of fertility (the time when a woman can become pregnant) is highly variable between women, and can slightly change for each woman over the course of her lifespan. Humans are considered to have concealed ovulation because there is no outward physiological sign, e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla ( hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla (cetaceans and even-toed ungulates), and the Carnivora ( cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, toget ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Menstrual Cycle
The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that make pregnancy possible. The ovarian cycle controls the production and release of eggs and the cyclic release of estrogen and progesterone. The uterine cycle governs the preparation and maintenance of the lining of the uterus (womb) to receive an embryo. These cycles are concurrent and coordinated, normally last between 21 and 35 days, with a median length of 28 days, and continue for about 30–45 years. Naturally occurring hormones drive the cycles; the cyclical rise and fall of the follicle stimulating hormone prompts the production and growth of oocytes (immature egg cells). The hormone estrogen stimulates the uterus lining ( endometrium) to thicken to accommodate an embryo should fertilization occur. The blood supply of the thickened lining provides nutrients to a successfully implanted embryo. If implantation does n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Sexual Behaviour
Animal sexual behaviour takes many different forms, including within the same species. Common mating or reproductively motivated systems include monogamy, polygyny, polyandry, polygamy and promiscuity. Other sexual behaviour may be reproductively motivated (e.g. sex apparently due to duress or coercion and situational sexual behaviour) or non-reproductively motivated (e.g. homosexual sexual behaviour, bisexual sexual behaviour, cross-species sex, sexual arousal from objects or places, sex with dead animals, etc.). When animal sexual behaviour is reproductively motivated, it is often termed ''mating'' or ''copulation''; for most non-human mammals, mating and copulation occur at oestrus (the most fertile period in the mammalian female's reproductive cycle), which increases the chances of successful impregnation. Some animal sexual behaviour involves competition, sometimes fighting, between multiple males. Females often select males for mating only if they appear stron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Menstruation
Menstruation (also known as a period, among other colloquial terms) is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The menstrual cycle is characterized by the rise and fall of hormones. Menstruation is triggered by falling progesterone levels and is a sign that pregnancy has not occurred. The first period, a point in time known as menarche, usually begins between the ages of 12 and 15. Menstruation starting as young as 8 years would still be considered normal. The average age of the first period is generally later in the developing world, and earlier in the developed world. The typical length of time between the first day of one period and the first day of the next is 21 to 45 days in young women. In adults, the range is between 21 and 31 days with the average being 28 days. Bleeding usually lasts around 2 to 7 days. Periods stop during pregnancy and typically do not resume during the initial months of bre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovulation
Ovulation is the release of eggs from the ovaries. In women, this event occurs when the ovarian follicles rupture and release the secondary oocyte ovarian cells. After ovulation, during the luteal phase, the egg will be available to be fertilized by sperm. In addition, the uterine lining (endometrium) is thickened to be able to receive a fertilized egg. If no conception occurs, the uterine lining as well as the egg will be shed during menstruation. Process Ovulation occurs about midway through the menstrual cycle, after the follicular phase. The days in which a person is most fertile can be calculated based on the date of the last menstrual period and the length of a typical menstrual cycle. The few days surrounding ovulation (from approximately days 10 to 18 of a 28-day cycle), constitute the most fertile phase. The time from the beginning of the last menstrual period (LMP) until ovulation is, on average, 14.6 days, but with substantial variation among females and betw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproductive Hormone
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required for the correct development of animals, plants and fungi. Due to the broad definition of a hormone (as a signaling molecule that exerts its effects far from its site of production), numerous kinds of molecules can be classified as hormones. Among the substances that can be considered hormones, are eicosanoids (e.g. prostaglandins and thromboxanes), steroids (e.g. oestrogen and brassinosteroid), amino acid derivatives (e.g. epinephrine and auxin), protein or peptides (e.g. insulin and CLE peptides), and gases (e.g. ethylene and nitric oxide). Hormones are used to communicate between organs and tissues. In vertebrates, hormones are responsible for regulating a variety of physiological processes and behavioral activities such as digesti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovulation
Ovulation is the release of eggs from the ovaries. In women, this event occurs when the ovarian follicles rupture and release the secondary oocyte ovarian cells. After ovulation, during the luteal phase, the egg will be available to be fertilized by sperm. In addition, the uterine lining (endometrium) is thickened to be able to receive a fertilized egg. If no conception occurs, the uterine lining as well as the egg will be shed during menstruation. Process Ovulation occurs about midway through the menstrual cycle, after the follicular phase. The days in which a person is most fertile can be calculated based on the date of the last menstrual period and the length of a typical menstrual cycle. The few days surrounding ovulation (from approximately days 10 to 18 of a 28-day cycle), constitute the most fertile phase. The time from the beginning of the last menstrual period (LMP) until ovulation is, on average, 14.6 days, but with substantial variation among females and betw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mating Call
A mating call is the auditory signal used by animals to attract mates. It can occur in males or females, but literature is abundantly favored toward researching mating calls in females. In addition, mating calls are often the subject of mate choice, in which the preferences of one gender for a certain type of mating call can drive sexual selection in a species. This can result in sympatric speciation of some animals, where two species diverge from each other while living in the same environment. There are many different mechanisms to produce mating calls, which can be broadly categorized into vocalizations and mechanical calls. Vocalizations are considered as sounds produced by the larynx and are often seen in species of birds, mammals, amphibians, and insects. Mechanical calls refer to any other type of sound that the animal produces using unique body parts and/or tools for communication with potential mates. Examples include crickets that vibrate their wings, birds that flap thei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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