Endocrine - the Menstrual cycle

Question 1

which 3 body parts are involved in the menstrual cycle

Answer 1

hypothalamus, pituitary and ovaries

Question 2

what hormones are involved

Answer 2

GnRH, FSH, LH, estradiol, progesterone

Question 3

what are the 2 phases of the menstrual cycle

Answer 3

1. follicular phase (maturation of egg)

2. luteal phase

Question 4

does the follicular phase begin when oestrogen levels are high or low

Answer 4

follicular phase begins when the oestrogen levels are low

Question 5

what hormones does the anterior pituitary secrete to develop the follicle

Answer 5

FSH and LH

Question 6

what causes the uterine lining to thicken in the follicular phase

Answer 6

the granulosa cells around the egg enlarge

Question 7

what hormone do the granulosa cells release when they enlarge

Answer 7

oestrogen

Question 8

each follicle has the potential to release an egg for fertilisation. true?

Answer 8

true

Question 9

when does ovulation occur in the follicular phase

Answer 9

ovulation occurs at the peak of follicular growth, in response to LH surge

Question 10

how long are LSH and FSH released before the oocyte is released

Answer 10

3-4 days

Question 11

describe the process that allows release of ova into the Fallopian tubes

Answer 11

the wall of the follicle is digested by proteolytic enzymes.
this causes the follicle to rupture and release ova into Fallopian tubes

Question 12

what is the luteal phase also known as

Answer 12

the secretory phase

Question 13

why are the granulosa cells now yellow

Answer 13

due to the cholesterol

Question 14

what are the granulosa cells called in the luteal phase and what do they secrete

Answer 14

they are called the corpus luteum and secrete progesterone

the granulosa cells undergo luteinisation

Question 15

when is peak progesterone production noted

Answer 15

1 week after ovulation takes place

Question 16

what happens in menstruation to the corpus luteum and the progesterone levels

Answer 16

if there is no embryo, the corpus luteum begins to disintegrate

progesterone levels are reduced
the uterine lining detaches and menstruation begins

Question 17

what does the follicular phase end with

Answer 17

ovulation

Question 18

describe the differences in hormone release in follicular phase and luteal phase

Answer 18

oestrogen secreted in follicular phase

progesterone secreted in luteal phase

Question 19

describe the hormonal control of ovarian and menstrual cycles

Answer 19

GnRH (hypothalamus) –> acts on ant pit –> secretes FSH and LH

Question 20

what is the role of FSH

Answer 20

acts on ovaries
stimulates development of follicles
stimulate secretion of estradiol and ovulation

Question 21

what is the role of LH

Answer 21

acts on ovaries

stimulates follicle maturation, ovulation and development of corpeus luteum

Question 22

what hormone suppresses FSH production by the ant pit in order to select a dominant follicle

Answer 22

oestrogen

Question 23

at mid cycle in the luteal phase, what causes the surge of FSH and LH from anterior pituitary

Answer 23

the high levels of oestrogen at mid cycle causes hypothalamus to GnRH - this causes the surge of FSH and LH

Question 24

how is ovulation detected

Answer 24

most commonly LH measurement

at day 21, progesterone can also be used

Question 25

what hormone is released bu hypothalamus to act on anterior pituitary to produce FSH and LH

Answer 25

GnRH (gonadotrophin releasing hormone)