Unit 2 - Gonadotropins Flashcards
What are two gonadotropins released from the anterior pituitary?
Follicle stimulating hormone and luteinizing hormone
What is the chemical nature of FSH and LH?
they are both proteins
What is the secretion of gonadotropins controlled by?
GnRH (gonadotropin releasing hormone)
What are the phases of the estrous cycle?
proestrus, estrus, metestrus, diestrus or anestrus
What physiologic changes occur during proestrous?
Primordial follicle matures into primary follicle surrounding a primary oocyte, then into a tertiary follicle surrounding a primary oocyte and then into secondary oocyte surrounded by a mature follicle
What physiologic changes occur during estrous?
the secondary oocytes matures into an ovum and is released from the ovary
What physiologic changes occur during metestrus?
the empty follicle begins its transformation into the corpus luteum
What physiologic changes occur during diestrus?
the corpus luteum is fully formed
If an animal is not pregnant, what happens to the corpus luteum?
it regresses
What cells of the ovary secrete estrogen and progesterone?
granulosa cells
What cells produce androgens?
cells of the theca interna
What pituitary hormone stimulates the production of estrogen?
FSH turns androgens into estrogen
What pituitary hormone stimulates the production of progesterone?
the pre-ovulatory surge of LH
What pituitary hormone stimulates the production of androgens?
LH
What phase of the estrous cycle is dominated by ovarian secretion of estrogen?
proestrus
What phase of the estrous cycle is dominated by ovarian secretion of progesterone?
diestrus
What is the effect of progesterone on the endometrium?
it stimulates endometrial secretion in preparation for implantation
What is the effect of estrogen on the endometrium?
it stimulates endometrial proliferation
Why is negative estrogen feedback important?
it is important for FSH secretion to convert androgens into estrogens; want to produce high levels of estrogen to simulate ovulation
Why is positive estrogen feedback important?
it is important to stimulate an LH surge once high levels of estrogen are reached to trigger ovulation
What are the dynamics of gonadotropin release in males?
the onset of puberty causes the pituitary to start production of more gonadotropins; they are released in a steady fashion
What cells are the targets of pituitary gonadotropins in males?
sertoli cells and leydig cells
What gonadotropin influences sertoli cells?
FSH
What gonadotropin influences leydig cells?
LH
What cells of the testes are analogous to granulosa cells in the female?
sertoli cells
What cells of the testes are analogous to theca cells in the female?
leydig cells
What cells secrete testosterone?
leydig cells
What is the function of chorionic gonadotropin?
it rescues the corpus luteum from regression by continuing to produce progesterone
What is chorionic gonadotropin produced by and in what species?
produced by human trophoblastic cells of the blastocyst
What is the function of interferon tau?
it is similar to chorionic gonadotropin; it rescues the regression of corpeus luteum
What species produces interferon tau and by what cells?
produced by bovine and ovine trophoblasts
What is placental lactogen?
a GH and prolactin analog that supports maternal metabolism and initiates milk synthesis and antagonizes maternal insulin
What is relaxin?
a chemicasl that relaxes pelvic ligaments, increases oxytocin synthesis for the preparation of partuition
