eek 5 Flashcards
range of normal menstrual cycle? menses length
21-35days
3-8days
when does ovulation usually occur in normal menstrual cycle? how much blood is normally lost?
day 14
30ml
what is menarche
when periods start
what are the three stages of ovarian cycle?
follicular, ovulation, luteal
what are the oestrogen levels when follicular stage begins/why does it occur?
low (oestrogen)
what stimulates follicle to develop?
Anterior pituitary secretes FSH and LH [stimulation follicle to develop]
what happens in development of follicle/follicular stage?
- A leading follicle develops
- Granulosa cells around egg enlarge, releasing estrogen
- This causes this uterine lining to thicken
[BASICALLY:During this phase, the ovarian follicles mature and get ready to release an egg]
what are the stages of the uterine cycle?
menses, proliferative, secretory
why does ovulation occur?
Happens at the peak of follicular growth in response to LH surge
what happens in ovulation?
[BASICALLY:second phase of the ovarian cycle in which a mature egg is released from the ovarian follicles into the oviduct]
- levels of estradiol reduce
- massive LH peak (positive feedback mechanism due to prolonged exposure to estradoil)
- proteolytic enzymes and prostaglandins are activated, → digestion of the follicle wall collagen → Follicle ruptures, releasing ova into the Fallopian tubes.
what is the luteal phase?
final phase of the ovarian cycle and it corresponds to the secretory phase of the uterine cycle; the lining of uterus gets thicker to prepare for a possible pregnancy
what is a corpus luteum?
It is the remains of the ovarian follicle that has released a mature ovum during a previous ovulation.
what does the corpus luteum do?
produce high levels of progesterone (peak at 1 week post-ovulation)
what happens to the corpus luteum
if pregnant - embryo will release hormones to preserve corpus luteum
if non-pregnant - stops progesterone, decays, uterine lining detaches, expelled by menstruation
what is expelled in menstruation? how long does this take?
Tissue, blood, unfertilized egg all discharged
Can take from 3-7 days
what is the HPO (hypothalamus-pituitary-ovary axis) hormones?
GnRH (Gonadotropin-releasing hormone) stimulates follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from ant pit.
what part of the hypothalamus is responsible for producing GnRH?
Arcuate nucleus
there are two parts of the ovary (outer cortex and inner medulla), which contains follicles?
outer cortex
what attaches the ovaries tot the pelvic wall?
the IP ligament [suspensory ligament of the ovary, also infundibulopelvic ligament]
what is the endometrium? what increases its thickness?
basal layer and superfuical layer of uterus (thickens in response to oestrogen)
what cause the endometrium to slough off?
Lack of hCG and progesterone
what is GnRH?
- gonadotropin releasing hormone
- is a deca peptide hormones
how many types of GnRH are there? which important?
3 types of GnRH hormone
GnRH 1 is responsible for the reproductive function (released in pulsatile manner, t1/2=2-4mins)
what is FSH?
- follicle-stimulating hormone
- glycoprotein, t1/2 - hours