Menstrual Cycle Key words Stimulate, Inhibit, Womb, Mature, FSH, LH, Oestrogen, Progesterone
Objectives By the end of the lesson I: Can explain the role of FSH, LH, and oestrogen in the menstrual cycle Explain how each of the hormones affect each other Explain the role of FSH as a fertility drug
Match up the key words with definitions Ovulation 2 of 3 Female Sex hormone Menstrual cycle Release of egg cell from ovary Oestrogen Male sex hormone Follicle Fluid filled structure in which the ovum matures in the ovary Progesterone 28 day cycle controlled by hormones where lining of uterus is released. Testosterone
Hormones are chemicals that act like messengers Hormones are chemicals that act like messengers. They are secreted by glands and carried in the blood from organ to organ. hormone hormone memo To: cells From: ovary Start puberty now! ovary Cells in different parts of the body recognize the hormones and respond by making changes.
Where are the major glands of the body? pituitary gland thyroid pancreas adrenal glands ovaries (females) testes (males)
Sex hormones ovaries (females) testes (males) In males, the testes produce the sex hormone testosterone, which makes male secondary sexual characteristics develop. In females, the ovaries produce the sex hormones oestrogen and progesterone. These make female secondary sexual characteristics develop and are involved in fertility and the menstrual cycle.
The pituitary gland The pituitary gland is a pea-sized gland at the base of the brain. It releases many hormones and controls several other glands in the body. YOU MUST KNOW WHERE EACH OF THE FEMALE SEX HORMONES ARE PRODUCED WHAT EFFECT THEY HAVE ON EGG PRODUCTION HOW EACH HORMONE AFFECTS THE PRODUCTION OF THE OTHERS pituitary gland The pituitary gland produces two hormones involved in fertility: follicle stimulating hormone (FSH) luteinizing hormone (LH).
Teacher notes This true-or-false quiz could be used as a starter exercise to work on hormones and fertility. Students could be given coloured traffic light cards (red = false, green = true) to vote on the statements shown. To stretch students, they could be asked to explain their voting.
Teacher notes This nine-stage interactive animation shows the hormonal and physiological changes during the menstrual cycle. Suitable prompts could include: Start: What’s the first thing you notice when you are starting a period? Day 1-5: Why do you have periods anyway? FSH stands for follicle-stimulating hormone. What do you think it does? Day 5-14a: How long after a period are you most likely to get pregnant? Day 5-14b: Usually FSH only circulates in the blood for long enough to make 1 egg mature per month. What job might the oestrogen do? Day 5-14c: What could tell the ovary to release the egg? Day 14: How could the ovary make sure the womb is expecting the egg it has just released? Day 14-21: Has the egg been fertilized? Day 21-28: What will the pituitary gland do when it stops receiving progesterone?
IN SUMMARY HORMONE PRODUCED EFFECT FSH Pituitary gland Causes egg to mature Oestrogen to be produced OESTROGEN Ovaries Inhibits further production of FSH Stimulates production of LH Stimulate uterine lining to thicken ready for implantation LH PROGESTERONE Stimulates the mature egg to be released Stimulates the uterus to thicken ready for implantation Inhibits further production of LH When levels fall uterine lining breaks down Teacher notes This nine-stage interactive animation shows the hormonal and physiological changes during the menstrual cycle. Suitable prompts could include: Start: What’s the first thing you notice when you are starting a period? Day 1-5: Why do you have periods anyway? FSH stands for follicle-stimulating hormone. What do you think it does? Day 5-14a: How long after a period are you most likely to get pregnant? Day 5-14b: Usually FSH only circulates in the blood for long enough to make 1 egg mature per month. What job might the oestrogen do? Day 5-14c: What could tell the ovary to release the egg? Day 14: How could the ovary make sure the womb is expecting the egg it has just released? Day 14-21: Has the egg been fertilized? Day 21-28: What will the pituitary gland do when it stops receiving progesterone?
Inside the ovary Day 15-28: empty follicle turns into corpus luteum (yellow body) immature eggs Day 1-13: egg developing inside the growing follicle Day 14: ovulation – egg released from follicle Teacher notes It may be worth pointing out to students that this image shows a summary of how the ovary looks over one month, and is not a representation of an ovary at a fixed point in time.
days after start of period uterus lining thickness The lining of the uterus becomes thicker with blood vessels and more stable during the menstrual cycle. Why is this important? 2 10 6 8 4 12 14 16 18 20 22 24 26 28 days after start of period uterus lining thickness period A fertilized egg will bury itself (implant) in the uterus lining. The egg needs a plentiful supply of oxygen and nutrients to develop.
Questions Using your graph of the menstrual cycle i) Mark the letter A on the point where ovulation is most likely to take place ii) Mark the letter B where the female is most fertile iii) Mark the letter C where menstruation is most likely to occur
Pregnancy If the egg is fertilized, the uterus lining must not break down otherwise the fertilized egg will not develop. progesterone memo To: uterus From: corpus luteum Maintain uterus lining. egg fertilized: uterus lining maintained, egg implanted oestrogen memo To: pituitary From: corpus luteum Don’t send FSH. corpus luteum (structure that develops after the ovum is discharged but degenerates if no pregnancy): continues to produce progesterone and oestrogen
Teacher notes This ordering activity could be used as a plenary or revision exercise on the menstrual cycle. Mini-whiteboards could be used to make this a whole-class exercise.
The role of Hormones in the menstrual cycle FSH released from pituitary gland. Produces follicle on ovary and stimulates egg to mature. If fertilisation occurs the yellow body will secrete progesterone, until placenta is formed and then takes over. If no fertilisation occurs yellow body disappears and progesterone levels decrease. This causes uterus lining to shed and menstruation occurs. Follicle secretes oestrogen. High oestrogen levels makes uterus lining thick and spongy and stops the release of FSH from pituitary LH released from pituitary. LH triggers ovulation (release of egg cell) Empty follicle (yellow body) secretes progesterone. Progesterone stops further ovulation and prevents shedding of uterus lining.
Objectives By the end of the lesson I: Can explain the role of FSH, LH, and oestrogen in the menstrual cycle Explain how each of the hormones affect each other Explain the role of FSH as a fertility drug
Control of Fertility Key words Contraception, Fertility treatment
Objectives By the end of the lesson I: Identify the issues involved in contraception and fertility Provide a two-sided argument for each of the issues Describe the role of hormones in oral contraceptives.
STARTER Where is FSH produced? What effect does the production of oestrogen have on the production of FSH and LH? What does LH do? 3) LH stimulates the release of the mature egg from the ovary 2) Oestrogen inhibits the production of FSH and stimulates the production of LH 1) Pituitary gland
Contraceptive pills contain progesterone and need to be taken every day. How do they work? progesterone memo To: pituitary From: contraceptive pill Stop sending FSH. no FSH received: no egg maturing Contraceptive pills mimic pregnancy, which means that the ovaries do not produce any eggs.
What is infertility? Some couples are unable to conceive naturally. This is called infertility. What might be some of the causes of infertility? Men Women ovaries not releasing eggs poor quality sperm blocked fallopian tubes (carry eggs from the ovaries to the uterus) blocked or damaged tubes that carry sperm problems with the uterus lining low sperm count hormonal problems hormonal problems
How do fertility drugs work? Fertility drugs are used to help women who do not produce an egg every month. There are many different types of fertility drug but they all work by tricking the body into producing more eggs. FSH memo To: ovary From: fertility drug Get another egg ready and start making oestrogen. Some fertility drugs contain FSH. How do these work?
What is IVF? Sometimes, women have problems becoming pregnant even after using fertility drugs. When this happens, they can try in vitro fertilization, or IVF. In vitro is Latin for ‘in glass’ so IVF means fertilization that takes place outside of the body and in laboratory glassware. Babies born by IVF are sometimes called ‘test-tube’ babies. However, fertilization doesn’t take place in test-tubes but in a special dish.
Teacher notes This eight-part sequence looks at how IVF is used to treat infertility. Stage 5 mentions pre-implantation diagnosis (PGD) and pre-implantation screening (PGS). PGD is used to test for certain genetic diseases including cystic fibrosis, haemophilia, Huntingdon’s disease, sickle cell disease and some cancers. Some diseases, such as haemophilia and Duchenne muscular dystrophy, only affect males. If there is a family history of the disease, only female embryos will be selected and implanted. More recently, a new type of testing, called Pre-implantation Genetic Haplotyping (PGH), has been developed that enables a much larger number of genetic diseases to be identified. Some serious and life-threatening genetic diseases may possibly be treated with stem cells from a family member who has the same tissue type as the affected person. See the ‘Genes and Genetic Engineering’ presentation for more information on PGD.
IVF and multiple births Why does IVF increase the chances of multiple births?
Multiple births are more likely with IVF because more than one embryo is implanted into the uterus to increase the chance of a successful pregnancy. Around 20% of IVF births are twins (compared with 1.25% of normal births), and 0.5% are triplets. The number of triplets was much higher 15-20 years ago because more embryos were implanted at the same time. Teacher notes Data from the Human Fertilisation & Embryology Authority (www.hfea.gov.uk) Multiple births are the biggest risk of IVF for both the mother and babies. They are more likely to result in premature births, miscarriages, and long-term disability and ill health.
The cost of IVF IVF is expensive – around £3,000 for the treatment itself, plus extra costs for consultation with doctors, drugs and tests. Freezing embryos for further attempts at IVF also costs extra. Couples may need to try IVF several times (each attempt is called a cycle) before it is successful. About 25% of IVF treatments are funded by the NHS. Women aged between 23 and 39 years can get one free IVF cycle on the NHS. Photo credit: Pasquale Sorrentino / Science Photo Library Technician using a micro-needle to inject human sperm into a human egg cell. The Petri dish containing the egg cell is on the platform of a light microscope. This technique used in in vitro fertilization (IVF) is known as intracytoplasmic sperm injection (ICSI). The injected sperm fertilizes the egg. The resulting zygote is then grown in the lab until it reaches an early stage of embryonic development. It is then implanted in the uterus. Several embryos are usually implanted to give the greatest chance of a successful pregnancy. However, this can result in multiple births. IVF allows infertile couples to conceive a child. Teacher notes Data from the Human Fertilisation & Embryology Authority (www.hfea.gov.uk).
Teacher notes This evaluating opinions activity about the provision of free IVF. For example, students could be asked to get into groups and try to reach a consensus decision on whether they agree or disagree with the opinion on screen. Alternatively, students could be asked to vote (possibly with traffic light cards) or individual students could be asked at random to give their opinion and justify it. There are no correct answers for this activity.
Questions 2) Women that find it difficult to have children take FSH as part of their fertility treatment. Explain how FSH can help women to get pregnant. Explain why it is common for women that have this treatment to have multiple births? The contraceptive pill is given to women to prevent pregnancy
Objectives By the end of the lesson I: Identify the issues involved in contraception and fertility Provide a two-sided argument for each of the issues Describe the role of hormones in oral contraceptives.