The Menstrual Cycle and Hormones

Question 1

what happens at the start of the menstrual cycle?

Answer 1

the uterine lining break down and sheds

Question 2

what happens during the menstrual cycle?

Answer 2

1. the uterine lining breaks down and sheds
2. the pituitary gland has begun to produce increasing amounts of the hormone FSH
3. this tells the ovary to form a mature egg cell - a follicle develop with the maturing egg inside it - the follicle produces the hormone oestrogen
4. the lining of the uterus has been repaired after menstruation and has thickened - this repair and thickening of the uterus lining has been brought about by the hormone oestrogen
5. as oestrogen levels, rise they stop FSH production and trigger LH production in the pituitary gland - LH stimulates ovulation and the release of the mature egg from the ovary
6. after the egg has been released, it travels down the oviduct (fallopian tube) to the uterus - it is in the oviduct that fertilisation may happen, if sexual intercourse has taken place
7. what is left of the follicle in the ovary now forms a structure in the ovary called the corpus luteum - the corpus luteum makes another hormone called progesterone
8. later on in the pregnancy, the placenta secretes progesterone, taking over the role of the corpus luteum

Question 3

what is the first sign of preganancy?

Answer 3

when the woman’s monthly periods stop

Question 4

what is the function of the menstrual cycle?

Answer 4

to control the development of the lining of the uterus (womb) so that if the ovum is fertilised, the lining will be thick and ready to receive the fertilised egg - if the egg is not fertilised, the lining of the uterus is lost from the woman’s body as the flow of menstrual blood called a period

Question 5

what are the four hormones that control the menstrual cycle?

Answer 5

• FSH
• oestrogen
• LH
• progesterone

Question 6

what gland secretes FSH?

Answer 6

pituitary gland

Question 7

what organ does FSH target?

Answer 7

follicle in ovary

Question 8

what is the effect of FSH?

Answer 8

• follicle develops and ovum matures (not released yet)
• maturing follicle releases oestrogen

Question 9

what gland is oestrogen secreted from?

Answer 9

the ovary (follicle in ovary)

Question 10

what organ does oestrogen target?

Answer 10

pituitary gland and uterus lining

Question 11

what is the effect of oestrogen?

Answer 11

• inhibits FSH production (stops another ovum being matured)
• stimulates LH production
• thickens uterus lining

Question 12

what gland is LH secreted from?

Answer 12

pituitary gland

Question 13

what organ does LH target?

Answer 13

follicle in ovary

Question 14

what effect does LH have?

Answer 14

• ovulation - follicle on ovary releases mature ovum into oviduct
• remnant of follicle on ovary becomes corpus luteum

Question 15

what gland is progesterone secreted from?

Answer 15

the ovary (corpus luteum)

Question 16

what organ does progesterone target?

Answer 16

pituitary gland and uterus lining

Question 17

what is the effect of progesterone?

Answer 17

• FSH and LH inhibited (stops further ovum being matured and released)
• thickens of uterine lining maintained