Female Reproductive System – Menstrual Cycle, Hormones and Regulation

Female Reproductive System – Menstrual Cycle, Hormones and Regulation

100 Replies to “Female Reproductive System – Menstrual Cycle, Hormones and Regulation”

  1. If you're studying for your GCSEs, watch my illustrated video to learn about reproductive hormones at the right level 🙂

  2. Out of a lot the the medical education videos online, I find yours better because of the way you enunciate your words. It feels like your actually talking to us. As compared to most other videos they sound like robots talking at us. Thanks for the high quality free content you provide us.

  3. This was so straightforward. You know they never explain to girls in school what Is happening to our body our whole lives on a horomonal level. That's why I went searching and I found this. Really easy to understand. Thank you!!!!

  4. If estrogen inhibits LH release. What happens when to much free estrogen is within the body such as from pesticides, organic in organic Xenoestrogens Phytoestrogens etc bisphenol A, 4-nonylphenol, 4-tertoctylphenol.
    What happens when we introduce these endocrine disrupters into our systems? The medical literature on this stuff blows my mind.

    “Do EDC exposures impair fertility in men or women? Can they cause sexual organ malformations, stunted reproductive development, or testicular or breast cancer? Do fetal exposures to EDCs alter sex phenotypes? Do they change later gender-related neurobiological characteristics and behaviors such as play activity and spatial ability? Could such exposures even be involved in the etiology of children born with ambiguous gender?
    EDCs include a spectrum of substances that can be loosely classified according to their known or suspected activity in relation to sex hormone receptors and pathways.

    The most-studied and best known are the environmental estrogens, which mimic estradiol and bind to estrogen receptors (ERs). ER agonists include the pesticide methoxychlor, certain polychlorinated biphenyls (PCBs), bisphenol A (BPA; a high production volume chemical used to make polycarbonate plastic), pharmaceutical estrogens such as diethylstilbestrol (DES) and ethinyl estradiol, and phytoestrogens, which occur naturally in many plants, most notably in soybeans in the form of genistein and related substances. There are a few known ER antagonists, or antiestrogens. Antiandrogens, or androgen receptor (AR) antagonists, include the fungicide vinclozolin, the DDT metabolite p,p′-DDE, certain phthalates (a group of chemicals used to soften polyvinyl chloride plastics), and certain other PCBs. And there are other types of EDCs that affect particular endocrine targets. The various EDCs differ greatly in their potencies relative to natural hormones, and in their affinity for target receptors. Some have been shown to act via non–receptor-mediated mechanisms, for example by interfering with hormone synthesis.
    In many well-documented cases of high-level fetal exposures to known EDCs such as DES, certain PCBs, and DDT, the answer to the question of whether exposure is associated with gender-related effects is clearly yes. But high-level exposures such as these are relatively rare and isolated. The debate today centers on low-dose exposures—generally defined as doses that approximate environmentally relevant levels—and the idea that low-dose intrauterine exposure to some EDCs during certain critical windows of development can have profound, permanent impacts on subsequent fetal development and adult outcomes.”

    “The endocrine system, comprising the hypothalamus, pituitary, testes, ovaries, thyroid, adrenals, and pancreas, is one of the body’s key communications networks. It regulates the function of specific tissues and organs by secreting hormones that act as precise chemical messengers. Development and regulation of the reproductive system is one of the major functions of the endocrine system.
    Sex determination and development begin early in gestation, with the differentiation of the embryonic gonad into either testes or ovaries. If the Sry gene is present on the Y chromosome, it will, when activated, trigger a complex cascade of hormonal events that ultimately results in the birth of a baby boy with all of the requisite male equipment in place and functioning properly. In the absence of the Sry gene, the end product of the process will be a baby girl. The female phenotype is considered to be the “default” pathway for mammalian reproductive development.

    These studies showed that in multiple-birth species it was possible for adjacently positioned male and female fetuses to transmit tiny amounts of hormones to each other, with pronounced phenotypic consequences. “We found that a difference of about a part per billion of testosterone and about twenty parts per trillion of estradiol [endogenous estrogen] actually predict entirely different brain structures, behavioral traits, enzyme levels, and receptor levels in tissues, hormonal levels in the blood—there is nothing you look for that . . . doesn’t differ in these animals,” says vom Saal.
    Such a delicately timed and precisely controlled process presents a myriad of opportunities for perturbation from exposure to EDCs. These chemicals mimic hormones, and can disrupt differentiation and development in a wide variety of ways, by duplicating, exaggerating, blocking, or altering hormonal responses.”

    Also, tissues are rapidly dividing and differentiating in the fetus, and such a high level of cell activity is vulnerable to disruption of normal development. With such small body mass in the fetus and child compared to an adult, exposure levels may be amplified in terms of relative dosages reaching target tissues. And sometimes, exogenous EDCs may show very low binding to plasma hormone-binding proteins and thus roam the body in an unbound state, with unknown effects.
    Much of what remains to be discovered about the impacts of EDC exposures on the fetus relates to a new concept called the developmental origins of health and disease (until recently known more commonly as the fetal basis of adult disease). “People are just now recognizing that this is indeed a possibility,” says NIEHS scientist Retha Newbold, a pioneer in the study of endocrine disruption who has spent decades researching the effects of exogenous estrogens, particularly DES. “Developmental exposure to low doses of EDCs may not lead to malformation or to anything you can look at and immediately recognize as a problem,” she says. “But it still could have long-term effects, such as alterations in metabolism, alterations causing cancer later on, or alterations causing infertility.”

    Seriously 😒 that’s scary to say the least… and there is much more to this.

    What’s your view?

  5. You saved my life with this video. I was having a difficult time with finding out which hormone is secred when and why but this made it very clear. Thank you!!!

  6. Took A&P 3 years ago. Watching back now in DMS school; still as amazingly helpful as it was then. Thanks for this gift!

  7. It’s not completely wrong
    But to start with gnrh is secreted in a pulsatile manner and not linear and the FSH doesn’t drop initially
    It increases and not a dropping level or a steady level instead it starts increasing to have a primary peak around the 6th day and then it drops and again a secondary peak at around the 12th or 13th day
    First peak is due to the fading corpus luteum to reach a peak after which due to the rising levels of the estrogen it drops after the peak………..second peak is due to the rising pulsatility of Gnrh which also stimulates LH and Second peak onFSH

  8. Try out the “Gοfαt Fanvuko” (Goοgle it) when you`re an infertile partners. The results of Western medicine didn`t make me happy. Nevertheless, my pregnancy was successful right after getting a proper diet and going through planned acupuncture treatments for a couple of months. Witnessing my year old daughter roaming around the house is genuinely wonderful. Check Goοgle to understand more about this great plan..

  9. I read somewhere that estrogen starts causing positive feedback when there is only one dominant follicle, is this correct ? Thanks.

  10. Finally starting to understand … thanks to ViolinMD who mentioned your channel in a video. Thank you so much for all the ressources and explanations you give, it is the most helpful videos I’ve found. Between you and NinjaNerd I might have a chance at passing my physio exam 😀 thank you so much

  11. LH stays constant due to negative feedback and FSH stays constant due to inhibin, is that correct ? Great video.

  12. oestrogen at moderate levels such as in the luteal phase should cause a positive feedback on the hypothalamus, increasing LH and FSH right? so why is it used in combine oral contraceptives?

  13. Hi! I'm taking my units in Anatomy and Physiology this semester and your videos are really great! I could easily visualize the contents in my book by just watching your collection! Thank you so much 😀 . Greetings from Philippines!

  14. Well done! Great detail! Thank you! I do wish you had panned back (is that even possible?) or somehow captured the completed drawing all in one frame. It would be helpful to be able to review the entire drawing.

  15. i would like to make a correction here, the menstrual cycle has 3 phases which are menstrual, proliferative and secretory phase, the ovarian cycle has two phases which are mentioned by the video follicular phase and luteal phase

  16. I've been struggling the learn the menstrual cycle for the MCAT for months. Every review book I came past just put up a picture of that stupid graph and I didn't understand anything until I found this video. Saying this video is a lifesaver is an understatement. Armando, you not only explained this concept amazingly but your approach of explaining WHY each step happened made this topic seem so easy. Thank you, seriously.

  17. 14:56, this right here ladies and gentlemen, is a fucking masterpiece!

    Thank you for the most clear, understandable, and awesome explanation!

    I hope you framed it and put it on a wall or donated it to a museum or something

  18. question, should a women then struggle to ovulate or ovulate only day 29/30 will a oestrogen based birth control such as qlairs used only for a week in folical phase then not help stimulate ovulation, please note I am only a normal women not a med student asking a simple question

  19. I'm a psych major. This video is quite excellent at explaining the menstrual cycle. In particular, it explains so clearly the roles that GRH, FSH and LH play. Before watching this video, I was trying to understand the menstrual cycle by reading the textbook. Frankly, I got lost pretty easily. This video makes it easier to understand AND retain. Thanks.

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