endocrine control of the reproductive system Flashcards
what are the 2 main structures responsible for hormonal regulation
- hypothalamus
- anterior pituitary gland
what is the function of the hypothalamus
- controls pituitary hormone release
what 2 hormones released by the hypothalamus are related to reproduction
- gondaotropin releasing hormone (GnRH)
- prolactin inhibiting hormone (PIH/Dopamine)
what are the 3 main functions of the pituitary gland in terms of reproduction
- stimulates production of oestrogen, progesterone in females
- controls ovulation and pregnancy
- controls testosterone production and spermatogenesis
what are 3 hormones released by the pituitary gland
- follicle stimulating hormone (FSH)
- Luteinizing hormone (LH)
- Prolactin (PRL)
describe the process of the hypothalamic pituitary axis
- hypothalamus secretes GnRH
- this stimulates the anterior pituitary gland to release LH/FSH
- this then effects the gonads causing the testis to produce testosterone and the ovaries to produce oestrogen and progestogen
what is Kisspeptin
a group of hypothalamic peptides that are essential for normal human fertility
e.g Kisspeptin —> GnRH —> LH/FSH —–> Gonads
describe how female puberty starts
- begins with gradual increase in pulsatile GnRH secretion by hypothalamus
- release of LH/FSH (Kisspeptin)
at what age range does female puberty begin
11-16
the first few cycles of female puberty are anovulatory, what does this mean
- not ovulating/releasing an egg
what is thelarche
beginning of breast development
describe starting of puberty in boys
from ages of 13, increased production of GnRH
- causing testosterone level changes
what is spermatogonia
undifferentiated male germ cell
what happens to spermatogonia at puberty
undergoes mitosis
what does it mean when a mammalian embryo, the gonad is bipotential
can from ovary or testis
- the undifferentiated gonand consists of precursor cell types that can follow either the female or male pathway
what are the 4 phases of the menstural cycle
- menstural phase
- follicular phase
- ovulation phase
- luteal phase
what are the 3 phases of the ovarian cycle
- follicular phase
- ovulation
3, luteal phase
what happens during each phase of the ovarian cycle
follicular phase= follicule grows
ovulation - follicle released
luteal phase - corpus luteum forms then degenerates
at what stage of the ovarial cycle is FSH/LH levels hgihest
Just prior to ovulation (day 14)
at what stage of the ovarian cycle is progesterone levels highest
luteal phase (around 21 days)
what arteries supply the vaginal, uterus and ovaries
vagina = vaginal artery
uterus = uterine artery
ovary = ovarian artery
egg does not become fertilized, the lining of the uterus (endometrium) is shed during menstruation, describe the variation in thickness of endometrium over the menstural cycle
- menstural phase / follicular phase = very thin endometrium
- proliferative phase / ovulation = growing endometrium
- secretory pro gestational phase / luteal phase = endometrium thickness at a maximum
what is the function of FSH
triggers the growth of eggs in the ovaries and gets the eggs ready for ovulation.
what is function of LH
LH stimulates steroid release from the ovaries, ovulation, and the release of progesterone after ovulation by the corpus luteum
what is the function of progesterone and where’s it made/released
to prepare the endometrium (lining of your uterus) for a fertilized egg to implant and grow
- corpus luteum in ovary
what is function of oestrogen and where is it made
produced in your ovaries and helps your body develop pubic hair, breasts, and a regular menstrual cycle (periods).
-stimulate growth of organs important for reproduction
- stim bone growth
- increase body metabolic rate
- increase fat deposition in subcutaneous tissue
- softening and better vascularisation of skin etc
describe why during the ovulation phase there is LH/FSH surge and decline in oestrogen
- after follicle phase/ follicle growth, collagenase (enzyme) digests the follicle wall
- the follicle ruptures = ovulation (egg released)
- as a result, oestrogen levels drop to prevent further ovulation (only one egg at a time)
what happens during the luteal phase
- ruptured follicle transforms to corpus luteum through luteinization
- yellow comes from cholesterol (precursor of steroid hormones)
- corpus luteum secretes progesterone, which is dominant hormone of 2nd half of cycle
what is the process called of follicle turning into corpus luteum
lutenization