10. Menstruation Cycle (Lopez) Flashcards
What cells produce inhibins and activins in the female?
Granulosa cells.
What is the signal for the destruction of the endometrium?
Low levels of progesterone and estrogen.
When is a female’s basal body temperature the lowest?
What hormone causes this change?
Just before ovulation in the follicular phase.
The increase in estrogen causes a brief drop in basal body temperature.
Luteinization occurs at the same time as a spike in which hormone?
Luteinizing hormone.
Which cells in the growing follicle produces androstenedione and testosterone?
Theca cells.
Theca cells express receptors for which androgen, luteinizing hormone or follicle stimulating hormone?
Theca cells = LH (luteinizing hormone) receptor.
When does the follicle become gonadotropin dependent?
Upon development of the antrum.
What is the function of the corona radiata?
Maintains a connection with oocyte.
Allows the fimbrae to connect with the released oocyte.
Which anterior pituitary hormone, LH or FSH, is favored by high and low frequency GnRH secretion?
LH is favored by high-frequency GnRH secretion.
FSH is favored by low-frequency GnRH secretion.
What is the nucleolar channel system?
When is the nucleolar channel system developed, in which hormone stimulates its formation?
The nucleolar channel system is a network of interdigitated tubes within the nucleolus of the endometrial epithelial cells.
The nucleolar channel system is stimulated by progesterone in the early secretory phase of the endometrial cycle.
When is metaphase II completed in the female gamete?
Upon fertilization.
What is the function of inhibins?
Inhibition of the transcription of FSH.
What enzyme catalyzes the conversion of estrone into estradiol?
17β-hydroxysteroid dehydrogenase
How do the granulosa cells begin secreting progesterone during the luteal phase?
They secrete angiogenic hormones which bring blood vessels closer to them, which allows them to accept cholesterol directly. They then utilize cholesterol desmolase and 3β-hydroxysteroid dehydrogenase to convert that cholesterol into progesterone.
Which cells in the growing follicle convert testosterone and androstenedione into estradiol-17β?
What hormone stimulates this conversion?
The mural granulosa cells.
FSH
During which phase of the ovulatory cycle will a female’s basal body temperature be the highest?
Which hormone stimulates this increase?
What other, similar hormone can increase basal body temperature in a female?
During the luteal phase.
Progesterone.
hCG can also increase basal body temperature in the event of pregnancy.
What hormonal value would we expect to see in someone with menopause?
Reduced estrogen and inhibin.
Increased FSH and LH due to a lack of feedback from estrogen and inhibin.
What cells produce angiogenic factors to vascularize the corpus luteum?
Granulosa cells.
Describe the nine steps of the hormonal regulation of the menstrual cycle.
Granulosa cells express receptors for which hormone, luteinizing hormone or follicle stimulating hormone?
Both. This allows them to maintain high levels of aromatase even when FSH levels are declining.
Where does the conversion of estradiol and estrone into estriol occur?
What is estriol?
Within the liver.
A weaker version of estrogen even than esterone.
When do decidual cells differentiate from stromal cells, and what hormone stimulates this process?
Decidual cells are differentiated from stromal cells in the middle to late secretory phase of the endometrial cycle. They are stimulated by progesterone.
What event triggers the early oocyte in females to pass prophase I and enter metaphase II?
The LH surge.
(Gamete is still diploid, since it has not completed metaphase II.)
What is the basic mechanism of action of the oral contraceptive pill?
What is the progestin affect?
Exogenous androgens feedback and decrease the levels of LH and FSH.
This creates an environment in which the LH and FSH are insufficient to cause folliculogenesis and ovulation (deletes the LH surge).
The progestin effect is the increase in viscosity of the cervical mucus under the effect of progestins, which decreases the mobility of sperm and the egg decreasing the chance of fertilization.
