Repro 1 Flashcards
these are clusters of neuronal bodies in hypothalamus, each has specific function
hypothalamic nuclei
GnRH is released by the _____ and ________, causing a release of gonadotropins from pituitary
surge centre and tonic centre (hypothalamus)
_______ consists of adenohypophysis (anterior lobe) and nuerohypophysis (posterior lobe)
pituitary gland or hypophysis
the surge centre and tonic centre (parts of hypothalamus) communicate with the adenophypophysis (part of pituitary) via the
hypothalamo-hypophyseal portal system (HHPS)
GnRH released from the hypothalamus ends up in which part of the pituitary
adenohypophysis (via the HHPS, so don’t get diluted by general circulation)
neurons in PVN and supraoptic nuclei synthesize this hormone which initiaties contractions for parturition and milk secretion
oxytocin
the hypothalamus synthesizes what hormone
GnRH, gonadotropin releasing hormone
oxytocin has what 2 functions (for repro)
initiates contractions for parturition and milk secretion
the adenohypophysis (anterior pituitary) releases what 3 gonadotropin hormones
FSH, LH, prolactin (FSH and LH are the main ones)
what does FSH do
stimulates follicular development in ovary
what does LH do
induces ovulation of mature follicles form ovary and luteinizes (converts to luteal cells) follicular cells of ovulated follicle, leading to formation of CL
what does prolactin do
inhibits FSH and GnRH
what are the female sex hormones
estrogen or estradiol 17B, and progesterone (steroid hormones)
what hormone does the corpus luteum produce
progesterone (steroid hormone)
the testes synthesize which hormone
testosterone (steroid hormone)
ovarian follicles develop in the ovarian cortex, except it which species
horses
the ________ is a primary oocyte surrounded by a layer of cuboidal follicular (granulosa) cells
primary follicle
the ______ contains an enlarged primary oocyte surrounded by several layers of follicular cells (granulosa cells)
secondary follicle
the ________ is a blister-like structure with a follicular cavity filled with follicular fluid, containing a primary oocyte with layers of surrounding granulosa cells
tertiary follicles
these cells secrete a glycoprotein that forms a protective shellfire the developing oocyte called the zone pellucida
granulosa cells
what is ovulation
releasing a mature oocyte ready to be fertilized from the mature follicle
after ovulation, the empty follicle will transform into this by luteinization (theca internal and granulosa cells become luteal cells)
luteinization
If no fertilization following ovulation, the CL will undergo regression/death, known as __________, and turn into a structure called _________, which will be eventually removed from the ovary.
luteolysis; corpus albicans
If the oocyte is fertilized and pregnancy establishes, the developing embryo send signals to the mother to maintain CL and continue __________ synthesis (this hormone is essential for maintaining pregnancy)
progesterone (a steroid hormone)
all steroid hormones start from one parent compound, which is
cholesterol
how do steroid hormones enter and exert effects on cells
they diffuse into cell and nucleus. so they do not need plasma membrane receptors to enter their target cells. however in the nucleus there are specific receptors for these hormones
how do gonadotropins enter and exert effects on cells
they interact with plasma membrane protein receptors, interacting with G proteins to activate adenylate cyclase and then activate protein kinases
progesterone, testosterone, and estradiol are all what kind of hormone
steroid hormones
FSH and LH are both what kind of hormone
gonadotropins
both the tonic and surge centres of the hypothalamus release GnRH. estrogen and P4 in combination exert negative feedback on tonic centre, maintaining release of GnRH at low frequency and amplitude. this tonic release of GnRH leads to tonic release of _____ [hormone], which leads to _____ [physiological process]
FSH; follicular development
both the tonic and surge centres of the hypothalamus release GnRH. estradiol exerts positive feedback on surge centre [when progesterone is low] leading to massive pulsatile (surge) release of GnR. surge GnRH release is followed by surge release of _____ [hormone] which leads to ___ [physiological process]
LH; ovulation
both the tonic and surge centres of the hypothalamus release GnRH. _______ exerts positive feedback on surge centre leading to massive pulsatile (surge) release of GnRH [as long as progesterone is low]. surge GnRH release is followed by surge release of LH which leads to ovulation
estradiol
both the tonic and surge centres of the hypothalamus release GnRH. ______ and _______ in combination exert negative feedback on tonic centre, maintaining release of GnRH at low frequency and amplitude. this tonic release of GnRH leads to tonic release of FSH, causing follicular development
progesterone (P4) and estrogen (E2)
at what part of estrous cycle are there are small follicles in ovary that secrete a bit of estrogen? (the LOW estrogen and LOW progesterone act to allow tonic release of GnRH, and therefore FSH secretion, causing follicular growth)
this describes the early follicular phase
developing follicles secrete
estrogen (E2)
in the preovulatory folicle, estrogen is being produced and once there is enough there will be a surge please of GnRH, causing a concomitant surge of LH, stimulating the final maturation of follicle and oocyte, leading to….
ovulation
the preovulatory follicle secretes _____ as well as estrogen). together these hormones inhibit the release of FSH
inhibin
progesterone inhibits the surge release of _____
GnRH
progesterone from a birth control implant mimics ______ [structure] to inhibit the surge release of ______, thereby preventing release of LH and ovulation
corpus luteum; LH
