Gynaecology Physiology Flashcards Preview

Obstetrics and Gynaecology > Gynaecology Physiology > Flashcards

Flashcards in Gynaecology Physiology Deck (10)
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1
Q

What is the effect of oestrogen on the hypothalamus and pituitary gland?

A

Negative feedback at moderate levels

Positive feedback at high levels

2
Q

What is the effect of progesterone on the hypothalamus and pituitary gland?

A

Negative feedback

3
Q

What hormones are seen in the menstrual cycle and where are they released from?

A
GnRH - Hypothalamus
FSH - Anterior Pituitary
LH - Anterior Pituitary
Oestrogen - Ovaries
Progesterone - Corpus luteum
4
Q

What stimulates ovulation?

A

LH surge due to +ve feedback from Oestrogen

5
Q

What are the phases of the menstrual cycle?

A

Follicular phase 0-14
Luteal phase 14-28
Menses 28-0

6
Q

What happens to the uterine wall throughout the cycle?

A

Build up in follicular and luteal phases until being shedded in menses

7
Q

What causes the menses?

A

Progesterone drop

Ovum not fertilised so corpus luteum –> corpus albicans and no longer produces progesterone

8
Q

Describe what happens in the menstrual cycle

long card

A

Low levels of sex steroids mean little -ve feedback –> FSH and LH rise

Oestrogen levels rise and negatively feeds back on FSH

Oestrogen levels high enough to +ve feedback –> LH surge

Ovulation

Follicle remains luteinised and secretes oestrogen and progesterone. -ve feedback on axis due to progesterone

Corpus luteum produce oestrogen, progesterone and inhibin to maintain fertilisation conditions

After 14 days corpus luteum regress - decrease in sex steroids - axis reset

9
Q

Why is FSH selectively inhibited?

A

Inhibin acts selectively on FSH to inhibit it

10
Q

Why does oestrogen still rise if FSH levels drop?

A

Oestrogen production becomes independent of FSH due to granulosa cells expressing LH receptors