Lecture 3: Female Reproductive System & Readings Flashcards
(79 cards)
What is ovarian steroidogenesis?
the production of steroid hormones like estrogen and progesterone
Ovarian steroidogenesis is a two-cell, two-gonadtropin model. Explain
The two cells required for ovaraian steroidogenesis are:
1. theca cells -
2. Lutenizing hormone
3. Granulosa cells
4. Follicle-stimulating Hormone
Explain the role of Theca cells in ovarian steroidogenesis.
Theca cells are stimulated by lutenizing hormone and convert cholesterol to androgens.
Theca cells stop at androgen as they do not have the ability to make estrogen
Explain the role of Granulosa Cells in steroidogenesis
granulosa cells are stimulated by follicle-stimulating hormone and convert androgens (from theca cells)
In the female reproductive tract the hormone produced from cholesterol is
Progesterone
Estradiol is produced from:
testosterone
Androstenedione will produce testosterone which will then produce estradiol
True or False
True
Why are steroids easily able to transverse potential membranes?
Steroids are lipids
Where are Progestins, Androgens and estrogens produced in the female reproductive tract?
In the ovarian follicle
Name the hormone that is produced by all major ovarian cell types: follicular granulose cells, theca cells and corpus luteum
Progestins - Progesterone
What crucial role does progesterone play in the female reproductive tract?
As a product of the corpus lute - during the luteal phase of the menstrual cycle & for the maintenance of pregnancy
What is the hormone that is most important as a precursor for the synthesis of estradiol?
Testosterone (Androgens)
Folliclular Atresia is associated with too much:
Testosterone
What is the hormone essential for the stimulation of follicular development and the onset of puberty
Estrogen - estradiol
The hypothalamic-pituitary-gonadal axis set into motion at puberty are similar in both male and female reproductive systems.
True or False?
True
In the female reproductive tract when the body levels of adipose tissue and leptin are low what happens?
Puberty is delayed
In the female reproductive tract which hormone will inhibit the hypothalamus from releasing GnRH?
estrogen
Gonadotropins (FSH and LH) levels increase for about four years. During this time females are still not ovulating. What does this mean?
During this time they are not able to become pregnant
What is menarche?
The first menstrual period
when does the female reproductive cycle become regular?
About 3 years after menarche
The levels of FSH and LH and ovarian hormones remain stable throughout the females life span.
True or False
False
The levels of FSH and LH, as well as ovarian hormones will fluctuate in reposnse to both negative and positive feedback mechanisms
Describe the regulation of the ovarian cycle.
GnRH stimulates FSH and LH secretion
FSH and LH stimulate follicle growth, mature and secrete sex hormones which cause them to release estrogen
Explain the negative feedback mechanism on regulation of ovarian cycle
Negative feedback inhibits gonadotropin release. As estrogen levels rise they signal the hypothalamus and anterior pituitary to inhibit the release of FSH
Inhibin released by the granulosa cells in reposnse to FSH will control the levels of FSH during this period and only the dominant cycle will survive the dip in FSH
Explain the positive feedback mechanism regulating the ovarian cycle
Positive feedback stimulates gonadotropin release. Once the dominant follicle becomes a mature vesicular follicle just before ovulation and produces high level of estrogens and exert positive feedback of the hypothalamus and anterior pituitray