Menstrual Cycle

• Lasts 28 days
• Puberty to menopause
• Ages 12 to early 50s
• Prepares women for pregnancy
• Symptoms due to hormonal changes: mood swings, stomach cramps, tiredness, breast tenderness 

• Oestrogen and progesterone are the hormones responsible - released by ovaries 
• Increase in oestrogen causes thickening of the uterus and triggers ovulation
• Progesterone increase maintains uterus lining 
• Oestrogen and progesterone levels decreasing causes the break down of uterus wall - menstruation 

1.Sperm enters vagina 

2. Cervix 

3. Uterus 

4. Oxidants 

5. Meets egg --> fertilisation 

• Prevents fertilisation

Physical barriers:

• Condom (98%) - barrier between fluids
• Diaphragm/Cap (92-96%) - barrier between fluids 

Chemical barrier:

• Hormone pill/Implant (99%) - releases hormones that stops ovulation 
• Combined pill increases oestrogen and progesterone - inhibits FSH to mature egg and inhibits LH to release egg

Hormonal Contraception:

• Progesterone like hormons on its self or with oestrogen
• Raises homone levels, prevents natural fall of homone concentrations at end of menstrual cycle

• Days 1-5: egg and linning lost, bleeding, menstruation 
• Days 6-12: cell walk starts to thicken, egg develops 
• Days 13-15: ovulation, egg is released
• Days 16-28: lining is still thickening, egg travels along oviduct, hopes to meet sperms and fertilise  

Unfertilised egg doesn't implant and reaches uterus the cycle begins again

• FSH + LH released from pituitary gland 
• Due to concentration of oestrogen + progesterone 
• Oestrogen increases the follicle matures 
• Follicle= cells in ovary around egg 
• Follicle becomes corpus luteum 
• Corpus Luteum= structure from where egg was released, releases progesterone 
• Progesterone released after ovulation 
• Corpus luteum must become inactive or menstruation will occur 

1. Low level of progesterone at start of cycle; allows menstruation 

2. FSH released from pituitary gland 

3. FSH stimulates growth of egg 

4. Maturing follicle stimulates oestrogen; causes uterus wall thickening 

5. High oestrogen concentration stimulates release of LH from pituitary glad 

6. High LH= Ovulation (egg release) 

7.Corpus luteum forms

8. Increase in progesterone; causes uterus lining to thicken 

9. Increase in progesterone inhibits release of FSH + LH 

10. End of menstruation,falling of progesterone+oestrogen triggers mentruation- cycle begins again  

ART:

• 'Assisted Reproductive Technique' 
• Increases chances of getting pregnant
• Helps people who cant conceive 

Clomifene Theory:

• Women who rarely release an egg 
• Drug that increase FSH + LH 

IVF:

• 'In Vitro Fertilisation' 
• Helps overcome blocked oviducts
• Low sperm counts 
• Cells tested for genetic disorders + other problems
• Healthy egg+sperm removed from donors 
• Fertilised in lab
• Placed back into womens uterus