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  2. Estrous cycle - Wikipedia

    en.wikipedia.org/wiki/Estrous_cycle

    A female dog is usually diestrous (goes into heat typically twice per year), although some breeds typically have one or three cycles per year. The proestrus is relatively long at 5 to 9 days, while the estrus may last 4 to 13 days, with a diestrus of 60 days followed by about 90 to 150 days of anestrus.

  3. Menstruation (mammal) - Wikipedia

    en.wikipedia.org/wiki/Menstruation_(mammal)

    This period of advertised fertility is known as oestrus, "estrus" or heat. [9] In species that experience estrus, females are generally only receptive to copulation while they are in heat [9] (dolphins are an exception). [10] In the estrous cycles of most placentals, if no fertilization takes place, the uterus reabsorbs the endometrium.

  4. Ovulatory shift hypothesis - Wikipedia

    en.wikipedia.org/wiki/Ovulatory_shift_hypothesis

    Female baboons and many other primates experience sexual swellings that advertise their fertility during estrus. Humans do not display any such obvious physical signals of fertility, but may still experience a subtle estrus-like state. Most female mammals experience reproductive fertility cycles.

  5. Lordosis behavior - Wikipedia

    en.wikipedia.org/wiki/Lordosis_behavior

    Lordosis behavior (/ l ɔːr ˈ d oʊ s ɪ s / [1]), also known as mammalian lordosis (Greek lordōsis, from lordos "bent backward" [1]) or presenting, is the naturally occurring body posture for sexual receptivity to copulation present in females of most mammals including rodents, elephants, cats, and humans.

  6. Menstruation - Wikipedia

    en.wikipedia.org/wiki/Menstruation

    Diagram illustrating how the uterus lining builds up and breaks down during the menstrual cycle 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 ...

  7. Human reproduction - Wikipedia

    en.wikipedia.org/wiki/Human_reproduction

    Human sexual reproduction, to produce offspring, begins with fertilization. Successful reproduction typically involves sexual intercourse between a healthy, sexually mature and fertile male and female. [1] During sexual intercourse, sperm cells are ejaculated into the vagina through the penis, resulting in fertilization of an ovum to form a ...

  8. Ovulation - Wikipedia

    en.wikipedia.org/wiki/Ovulation

    Ovulation is an important part of the menstrual cycle in female vertebrates where the egg cells are released from the ovaries as part of the ovarian cycle. In female humans ovulation typically occurs near the midpoint in the menstrual cycle and after the follicular phase. Ovulation is stimulated by an increase in luteinizing hormone (LH).

  9. Female reproductive system - Wikipedia

    en.wikipedia.org/wiki/Female_reproductive_system

    The human female reproductive system is made up of the internal and external sex organs that function in the reproduction of new offspring. The reproductive system is immature at birth and develops at puberty to be able to release matured ova from the ovaries , facilitate their fertilization , and create a protective environment for the ...