2 - Gynae - Menstrual Cycle and its disorders - Physiology

Question 1

normal ages/values/lengths

• menarche?
• menopause?
• menstruation length?
• blood loss?
• cycle length?
• no what?

Answer 1

• <16
• > 45
• <8d
• <80mL
• 23-35d
• no intermenstrual bleeding (IMB)

Question 2

how is puberty kicked in to action? what is normally the last manifestation of female puberty? the first and second parts?

Answer 2

HPA wakes up which wakes up ovaries
menarche av age 13y
9-11y breast dev
11-12y pubic hair

Question 3

what happens after 8 years

Answer 3

GnRH pulses incr amplitude and freq > pituitary FSH + LH release increases > stimulate oestrogen release from ovary

Question 4

what accompanies the 3 stages of puberty? what age is growth generally finished? what fuse?

Answer 4

growth spurt

16
epiphyses fuse

Question 5

The menstrual cycle

-hormonal changes cause what? and induce changes in the what? preparing it for what?

Answer 5

ovulation
endometrium of uterus
implantation if fertilisation occurs

Question 6

The menstrual cycle

• days 1-4 - called what?
• what happens

Answer 6

menstruation

endometrium is shed as hormonal support is withdrawn. myometrial contraction, can be painful, also occurs

Question 7

The menstrual cycle

• days 5-13 -called what?
• what induces follicular growth?
• follicles produce what? leading to?
• as oestradiol levels rise and reach max what happens? what else does oestradiol do?

Answer 7

proliferative phase

pulses of GnRH stim LH + FSH release inducing follicular growth

oestradiol and inhibin - suppresses FSH secretion in -ve feedback loop -> only one follicle/oocyte matures

a +ve feedback effect on Hypo and pituitary > LH sharp rise > 36h later ovulation occurs

oestradiol causes endometrium to reform and become proliferative - it thickens

Question 8

The menstrual cycle

• days 14-28 - called what?
• what become corpus luteum? this produced what? what does this do to the endometrium? when does corpus luteum start to fail? what happens as a result?

Answer 8

luteal/secretory phase

follicle from which egg was released becomes CL - prod oestradiol but more progesterone (peak levels at ~ 21d) - induces secretory changes in endometrium -> prepares for implantation - if egg not fertilised the CL starts to fail at end of luteal phase > prog and oestrogen levels fall > hormone support withdrawn and endometrium breaks down > menstruation follows > cycle restarts

Question 9

what canbe used to delay menstruation

Answer 9

continuous administration of exogenous progestogens > maintain secretory endometrium and delay menstruation