Menstrual Cycle 🩸

• Oestrogen 


  Produced in the ovaries

  Is involved in the menstrual cycle
• Stage 1 of the menstrual cycle

  DAY 1

  Menstruation begins

  Uterus lining breaks for about 4 days
• Menstrual cycle stage 2

  DAYS 4-14

  Uterus lining builds up again into a thick spongy layer full of blood vessels

  its ready to receive a fertilised egg
• Menstrual cycle stage 3

  DAY 14

  An egg develops and is released from the ovary

  This is ovulation
• Menstrual cycle stage 4

  uterus lining maintained till day 28. if no egg is fertilised the spongy lining along with the egg are released as a period.
• FOLLICLE STIMULATING HORMONE

  Produced in the pituitary gland

  causes an egg to mature in the ovaries of a follicle

  Stimulates ovaries to produce oestrogen
• OESTROGEN

  Hormone

  produced in ovaries

  causes uterus lining to grow

  stimulates release of LH

  inhibits release of FSH
• LUTEINISING HORMONE


  produced by the pituitary gland

  stimulates the release of an egg at day 14
• PROGESTERONE

  produced in ovaries by the remains of the follicle after ovulation

  maintains lining of the uterus

  when progesterone levels fall the uterus lining breaks down

  it inhibits the release of FSH
• How Oestrogen can reduce fertility

  Oestrogen inhibits FSH (which causes an egg to mature )

  If oestrogen levels are permanently high then eggs can not be released or fertilised and the production of eggs stops.
• How can progesterone reduce fertility

  It can stimulate the production of thick cervical mucus, which prevents fertilised eggs from implanting on the uterus lining. It also prevents sperm from reaching the egg.
• The Pill

  an oral contraceptive

  contains oestrogen and progesterone

  99% effective

  side effects include headaches and nausea

  doesnt protect you from stds
• The contraceptive patch

  a small patch containing oestrogen and progesterone

  it’s stuck to the skin

  it’s effects last for 1 week
• Contraceptive implant

  inserted under arm skin

  releases continuous progesterone

  prevents releases of eggs

  prevents sperm from swimming

  prevents fertilised eggs from implanting

  its effects last for around 3 years
• Intrauterine Device

  T shaped device inserted into the uterus

  Kills sperm and prevents fertilised eggs from implanting

  Can last from 5-10 years depending on the type
• What do plastic IUDs do

  release progesterone
• What do copper IUDs do

  prevent the sperm from swimming in the uterus
• What is a barrier

  a non hormonal form of contraception
• examples of barriers

  condoms - protect you from stds

  diaphragm

  spermicide
• How do avoid pregnancy without contraception

  Abstinence

  avoid sex during ovulation

  sterilisation
• How hormones can increase fertility

  FSH can be used as a fertility drug to stimulate ovulation

  This is typically for women who have low levels of FSH
• Cons of using hormones for fertility

  Doesn’t always work

  Having to repeat the process is expensive

  Too many eggs can be stimulated (twins ect)

  ^ that is risky
• IVF

  • Eggs collected from woman’s ovaries and fertilised in a lab with man’s sperm

  • Fertilised eggs grow into embryos in a laboratory incubator

  • Once embryos are tiny balls of cells, they are transferred into a woman’s uterus

  • FSH and LH are given before egg collection to stimulate many eggs maturing
• Cons of IVF

  Multiple births can happen if more than 1 embryo grows into a baby

  Success rate in UK is 26

  Women can have strong reactions to the hormones eg abdominal pain, vomit ing and dehydration
• Why people are against IVF

  unused embryos are destroyed

  could lead to selection of preferred characteristics eg gender and eye colour
• What occurs if an egg does not get fertilised

  the egg and the uterus lining are released as a period
• What gland do FSH and LH come from

  The pituitary gland
• Where are oestrogen and progesterone produced

  The ovaries
• GIVE A WAY THAT PROGESTERONE CAN PREVENT A PREGNANCY

  It stimulates the production of thick sticky cervical mucus which prevents any sperm from getting through and reaching the egg.
• HOW CAN OESTROGEN PREVENT A PREGNANCY

  Keeping oestrogen levels permanently high inhibits production of FSH, meaning no eggs can mature
• WHAT EFFECT DOES OESTROGEN HAVE ON FSH

  It inhibits it.
• WHAT IS THE ROLE OF FSH AND LH IN IVF

  They stimulate several eggs to mature
• WHY DID IVF INCREASE THE AMOUNT OF TWINS BORN

  FSH used in IVF

  this causes more eggs to mature

  and therefore created a higher chance of having twins as more than 1 embryo had a possibility of becoming fertilised .
• On what day does LH peak?

  Day 14