MENSTRUAL CYCLE + PREGNANCY Flashcards
What are primary sexual characteristics?
present during development in uterus (differences in reproductive organs etc) between male + female
What are secondary sexual characteristics?
changes that ocur during puberty
How are secondary sexual characteristics controlled?
controlled by release of hormones:
oestrogen in girls
testosterone in boys
EFFECTS OF OESTROGEN IN GIRLS
Breast develop
Body hair grows
Menstrual cycle begins
Hips get wider
EFFECTS OF TESTOSTERONE IN BOYS
Growth of penis + testis Growth of facial + body hair Muscles develop Voice breaks Testes start producing sperm
By what is the menstrual cycle controlled?
by hormones released from ovary + pituatary gland in the brain
Menstrual cycle: DAY 1-5
FSH from pituaritary gland tells ovary to mature an egg
Menstrual cycle: DAY 5
Follicle with egg starts to ripen
- as it matures, it produces oestrogen
(prevents production of further eggs, thickens uterus wall, released into bloodstream + tells pituaritary gland to switch off FSH)
Menstrual cycle: DAY 14
Pituitary gland produces LH which makes ovary release an egg.
Egg travels through fallopian tube to be fertilised
Empty follicle becomes corpus luteum
+ produces progesterone (making lining of uterus thicken even more to prepare for pregnancy)
OESTROGEN + PROGESTERONE prepare uterus to receive fertilised egg.
Menstrual cycle: DAY 28
If uterus doesnt receive fertilised egg, hormone production STOPS + uterus lining STOPS THICKENING.
menstruation will then occur (back to day 1)
How is the developing embryo protected?
Developing embryo is surrounded by amniotic sac which contains amniotic fluid (made from mothers plasma)
- this protects foetus during pregnancy by cushioning it from bumps to mothers abdomen
What is the role of placenta?
allows substances to diffuse from the mother’s blood to the foetus (e.g. oxygen and glucose).
Substances can also diffuse from the foetus to the mother’s blood (e.g. carbon dioxide and urea).
Why are women advised not to smoke during pregnancy?
Not all toxins are stopped from passsing through placenta (depends on size of molecule)
what does a drop in progesterone level cause?
menstruation
what happens when oestrogen levels rise?
causes uterus wall to thicken + egg to mature
