The Menstrual Cycle (Part 1 of 2) – Biology – Science – Get That C In your GCSE and IGCSE



hey class I mr. Thornton and I'm going to help you get that C in your GCSE this lesson the menstrual cycle and how that relates to fertility and the female contraceptive pill the whole process of the menstrual cycle is controlled by three hormones in particular which you need to know the names of they are FSH or follicle stimulating hormone the role that plays is in stimulating the follicles inside the ovaries to start an egg cell maturing ready to get released East region which among other things controls the thickness of the lining of the wall of the uterus and LH or luteinizing hormone which is what stimulates an egg to be released let's have a look at how the levels of these affect the different stages of the menstrual cycle in detail the pituitary gland buried deep under the brain is responsible for some of the hormones involved in the menstrual cycle the first stage of the menstrual cycle for the first four or five days is the stage when the lining of the uterus from the previous month is steadily breaking down and passing through the cervix and through the vagina during the woman's period at this time known as menstruation the level of FSH being produced by a woman's pituitary gland increases this increase in FSH stimulates the ovaries to do two things firstly a follicle within the ovaries will start to develop an egg that egg will be maturing for the next few days secondly the ovaries start to produce an increasing amount of estrogen the east region then goes on to have two effects of its own firstly this increasing level of Easter gene causes the lining of the uterus to start to thicken again secondly the increase in Easter gene causes the pituitary gland to stop making as much FSH and the levels of FSH for the pituitary gland produces a range of almonds and one of the other ones which it produces is LH or luteinizing hormone the level of LH in the body remains fairly low for most of the menstrual cycle but partway through the cycle it very suddenly and rapidly increases this sudden increase in LH stimulates the ovary to release the egg that's been maturing since the start of the menstrual cycle this is ovulation LH levels then fall quite rapidly and remain low for the rest of the menstrual cycle estrogen levels fall now that the uterus lining is thick enough to potentially be able to support a developing embryo and towards the end of the menstrual cycle in the last few days if a fertilized egg cell hasn't arrived and embedded itself in a uterus the uterus lining starts to break down finally FSH levels fall and remain low until it gets round to the start of the menstrual cycle again and the whole process begins once more this is a pretty complicated looking graph but don't worry no one's going to ask you to reproduce this from memory the things which you need to know about this are much more basic let me just run through those one more time just to pick out the key points which you need to be aware of firstly this whole process starts at the start of the menstrual cycle here in this period that we call menstruation where the uterus lining from the previous month passes out through the cervix and then through the vagina around about that time the level of FSH starts to increase remember that's produced in the pituitary and that's what causes a new egg to start maturing in the ovary here this is the egg which is going to be released later on in the month but it needs to start maturing right here at the start of the month it also stimulates the ovaries to start producing the east region and so the east region levels start going up because the FSH level went up now estrogen has two effects firstly when it gets high like this it reduces the levels of FSH it stops the pituitary producing as much and it also causes the lining of the uterus just here to start to thicken then around about the middle of the month the level of LH suddenly jumps up and that's the period that we call ovulation that's when an egg is released and it comes out of whichever ovary we're dealing with if it's then fertilized it can then embed it in the lining of the uterus but otherwise when we get towards the end of the month levels of estrogen drop again the lining of the uterus starts to break down and it's getting ready for the next cycle of menstruation which starts at the beginning of the next month that's all that you need to know about how these hormones influence the process of the menstrual cycle the process of menstruation and of ovulation in the second half of this lesson we'll look at how women can use the information about what the hormone levels in their bodies are doing throughout the menstrual cycle to control their own fertility for reasons such as fertility treatments and contraception good luck in your GCSEs everyone and if you found this lesson useful please use the buttons below to like subscribe or share thanks for watching

12 Replies to “The Menstrual Cycle (Part 1 of 2) – Biology – Science – Get That C In your GCSE and IGCSE”

  1. does this playlist cover the entirety of biology core as it seems to be missing adaption and the carbon cycle and diet and disease  just wondering as I am using your videos for mock revision and these videos seem to missing don't know if I just went passed it or what. Either way great videos helping me through my triple revision this and last year

  2. I think you need to do some more core videos for example the environment and antiseptics and viruses etc but you other video are helpful

  3. I think you need to do some more core videos for example the environment and antiseptics and viruses etc but you other video are helpful

  4. You're absolutely correct that I've skipped the role of progesterone in this video, well spotted!  That's because the video is for the current AQA Science A specification (which you can download for free, here: http://filestore.aqa.org.uk/subjects/AQA-4405-W-SP-14.PDF ), and on page 18 of that specification the exam board states "Knowledge of the role of progesterone in the natural menstrual cycle, including details of negative feedback, is not required."

    I'm not sure why they took this decision, but since I'm trying to keep the information in these videos to the bare minimum so as not to overload you while you revise, I thought I'd better leave it out too.  Other exam boards may expect you to know about progesterone, so if you're not doing an AQA exam, then I'd check with your teacher or have a look at the specification on that exam board's website.

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