MC full form
M – Menstrual
C – Cycle
The Menstrual Cycle( 28 Days long)
The four main hormones involved in the menstrual cycle
- Follicle stimulating hormone (FSH)
- Luteinizing hormoneor (LH)
There’s two phases of the menstrual cycle the typical menstrual cycle is 28 days long and each phase is 14 days long .
Two phases of the menstrual cycle
- Follicular Phase (ovum inside a follicle)
- Luteal phase (corpus luteum)
The first phase is the Follicular Phase and is called this because the egg which we also call the ovum is inside a follicle that’s developing.
The second phase is called the luteal phase because the egg has exited the ovary during ovulation and what’s left inside the ovary is called the corpus luteum.
In many women the cycle is different lengths for example 21 days or 35 days and the luteal phase or the second phase is always 14 days long so when the cycle is shorter then it means the follicular
phase is shorter and when it’s longer the follicular phase is longer and the luteal phase always remains 14 days long.
The body that released the hormones firstly in the middle of the brain you have the hypothalamus and the pituitary gland.
the pituitary is split into two parts the anterior part at the front and the posterior part at the back and these are responsible for regulating a large number of hormones in the body then you have the pelvic organs so there’s the vagina the uterus where the babies grow the fallopian tubes and the ovaries the ovaries are whether eggs develop and then when they’re released they get fertilized in the tubes and they travel down the fallopian tubes and settle in the uterus and that’s where the babies grow the lining of the uterus is called the endometrium.
It’s like a soft cushiony tissue that the fertilized egg will implant into and it has a great blood supply and is a great environment to support the growing baby and this is the area that breaks down and bleeds every month so that it can be renewed and refreshed for a fresh attempt at becoming pregnant.
Day one of the menstrual cycle at the very top the hypothalamus kicks everything off by releasing gana detroy and releasing hormone. This hormone is pretty self-explanatory, it does what it says on the tin. It causes the release of ganado try fans or follicle stimulating hormone and luteinizing hormone from the anterior pituitary gland. The main job of FSH is to stimulate the development of the follicles as the name would suggest and the main job of LH is to cause ovulation. Each ovary has a finite number of
immature eggs that are called primordial follicles and there’s about 200,000 of these in each ovary they lie waiting for the woman’s whole life from birth until the month that they become active so once a month at the start of the menstrual cycle follicle stimulating hormone stimulates 15 or 20 of these follicles to start developing within the ovaries and as the follicles develop the cells surrounding them called the granulosa cells secrete increasing amounts of estrogen.
Estrogen is a steroid sex hormone that acts on tissues with estrogen receptors to promote female secondary sexual characteristics. They stimulate the development of breast tissue and other female sex organs around puberty such as the vulva vagina and uterus. They also stimulate the blood vessels in the uterus and the development of the endometrium and they cause the mucus in the cervix to become thinner so that the sperm are able to penetrate it around the time of ovulation so that they can get into the uterus and get to the egg to fertilize it the east region also causes a negative feedback on the anterior pituitary and hypothalamus, so as the level of estrogen rises it suppresses the release of LH and FSH just before ovulation there’s a bit of a dip in estrogen as the follicles are getting ready to release the egg there’s a spike in luteinizing hormone that causes one of the follicles to reach the surface of the ovary and release the ovum or the unfertilized egg.
Ovulation happens at day 14 of a 28-day cycle at the luteal phase of the menstrual cycle the follicle that released the ovum collapses and becomes the corpus luteum. The corpus luteum secretes high levels of progesterone and progesterone is a steroid sex hormone as well it’s produced by the corpus luteum after ovulation and if pregnancy occurs then the placenta will take over the production of progesterone from around five to ten weeks of pregnancy progesterone acts on the tissues that have previously been stimulated by estrogen.