menstrual cycle

Question 1

4 stages

Answer 1

stage 1 - menstruation starts. uterus lining Breaks down for four days
stage 2 - uterus lining builds up again. Therefore today 14 into a thick spongy layer full of blood vessels ready to receive a fertilised egg.
stage 3 - Egg develops and is released - ovulation.
stage 4 - Wall is then maintained. If no fertilised egg has landed on uterus wall by day 28 cycle starts again

Question 2

FSH

Answer 2

1. produced in pituitary glands.
2. causes egg to mature. structure is a follicle
3. stimulates ovaries to produce oestrogen.
4. oestrogen then inhibits release of FSH

Question 3

Oestrogen

Answer 3

1. produced in ovaries
2. causes lining of the uterus to grow
3. Stimulates release of LH

Question 4

LH

Answer 4

1. Produced by pituitary gland

2. stimulates release of an egg at ovulation

Question 5

Progesterone

Answer 5

1. produced in ovaries by remains of follicle after ovulation
2. maintains the lining of uterus during second half of cycle. Level of progesterone falls, lining breaks down
3. Inhibits release of LH and FSH

Question 6

how embryo develops during pregnancy

Answer 6

1. once embryo is implanted, placenta develops, allows exchange of food oxygen and waste
2. amnion membrane forms, surrounds embryo and is full of amniotic fluid. This protects embryo against knocks and bumps

Question 7

placenta

Answer 7

mums blood gives ... to foetal blood
water by osmosis
amino acids by diffusion
oxygen by diffusion
calcium and iron by diffusion
fatty acids by diffusion 
gyclerol by diffusion
glucose by diffusion. 
urea and carbon dioxide diffuse from the foetal blood to mums blood