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How does the concentration of oestrogen affect and control the release of an egg during the menstrual cycle?
Pre-Ovulation (Day 2 -14)
The menstrual bleeding usually lasts a few days. From Day 2 on, the body is already starting to prepare itself for the next cycle. Under the influence of Follicle Stimulating Hormone (FSH) and LH (Luteinizing Hormone) from the pituitary gland, the ovarian follicle starts to manufacture and secrete estrogen. Estrogen causes the uterine lining to grow. About 15 to 20 eggs start to mature in each ovary during this period. Each egg is encased and protected in its own follicle. The follicles also produce estrogen, the hormone necessary for ovulation to eventually occur. The level of estrogen slowly rises during this period as the uterus lining thickens and starts its preparation to receive the egg if ovulation occurs. A race progresses for one follicle to become the largest. Eventually, ovulation occurs when one ovary releases an egg from the most dominant follicle.
Ovulation (Day 14-15)
Although it averages about two weeks, this race to release an egg can take anywhere from about 8 days to a month or longer to complete. The key factor that determines how long it will take before you ovulate is how soon your body reaches its estrogen threshold. The high levels of estrogen will trigger an abrupt surge of Luteinizing Hormone (LH). It's this LH surge that causes the egg to literally burst through the ovarian wall, usually within a day or so of the occurrence that we called ovulation. After ovulation, the egg tumbles out into the pelvic cavity, where it is quickly transported into the fallopian tubes. The remainder of the ruptured follicle (called the corpus luteum) recedes back to the ovary and begins an important task of secreting progesterone. Why is progesterone so important? It causes an increase in blood vessels to the uterine lining in order to provide nutrients for the fetus in case fertilization occurs. It also inhibits other eggs from developing, and causes the Basal Body Temperature (BBT) to rise about half a degree.
What else can I help you with?
What does oestrogen do in the menstrual cycle?
Several hormones are involved in the female menstrual cycle, the ovaries produces oestrogen which causes changes at puberty and helps control the menstrual cycle, and stimulates production of LH.
What is the relationship between oestrogen and ovulation?
Oestrogen plays a crucial role in the regulation of the menstrual cycle and ovulation. During the follicular phase, rising levels of oestrogen produced by developing follicles stimulate the thickening of the uterine lining and signal the pituitary gland to release luteinizing hormone (LH). This surge in LH triggers ovulation, leading to the release of an egg from the ovary. Thus, oestrogen is essential for both preparing the body for ovulation and facilitating the ovulation process itself.
What regulates estrogen and progesterone?
LH ( luteinising hormone) is stimulated by oestrogen and secreted by the pituitary gland. As oestrogen levels rise it will inhibit the production of FSH (follicle stimulating hormone) and will encourage the production of LH. As LH rises to a peak in the middle of the menstrual cycle, they will stimulate the release of a mature egg.
Why are oestrogen and progesterone in the contraseptive pill?
Hormones control the release of eggs, and Birth Control pills either regulate or prevent that release.
How are the events in the menstrual cycle triggered?
The events in the menstrual cycle are triggered by hormonal signals from the hypothalamus, pituitary gland, and ovaries. The release of hormones such as FSH (follicle-stimulating hormone) and LH (luteinizing hormone) control the development of ovarian follicles and the release of an egg during ovulation.
What system controls the ovarian and menstrual cycle?
The hypothalamus, pituitary gland, and ovaries work together to control the ovarian and menstrual cycle. The hypothalamus secretes gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These hormones then regulate the development and release of eggs from the ovaries, as well as the production of estrogen and progesterone.
What day does the LH reach its peak concentration?
The luteinizing hormone (LH) reaches its peak concentration around the middle of the menstrual cycle, approximately 24-48 hours before ovulation. This surge in LH triggers the release of the mature egg from the ovary.
What Two hormones secreted by the ovary?
Two hormones secreted by the ovary are estrogen and progesterone. Estrogen is responsible for the development of female reproductive organs and secondary sexual characteristics, while progesterone helps regulate the menstrual cycle and prepare the uterus for pregnancy.
What stimulate estrogen?
Oestrogen stimulates the hormone LH. LH is secreted in pituitary gland and stimulates the release of an egg
What day does LH reach its peak concentration?
Day 14
What hormone initiates menarche?
Gonadotropin-releasing hormone (GnRH) signals the pituitary gland to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which then stimulate the ovaries to produce estrogen. It is the increase in estrogen levels that triggers the start of menarche, the first menstrual period in a female.
The onset of puberty in both males and females is started by the secretion of?
Puberty is started by the Pituitary Gland (part of the Endocrine system) in the brain sending signals to release testosterone in boys and oestrogen & progesterone in girls. This mass release of the hormones is recognised by the body and begins the process of puberty.Also note that both boys and girls have testosterone and oestrogen, just in different amounts. Boys produce more testosterone and girls produce more oestrogen.
