Ovulation and Menstruation Flashcards
During which days of the menstrual cycle does the level of FSH increase? What happens to the follicle during this time?
Days 1-5, and 12-14. During this time, the follicle is developing, due to to increased levels of FSH
What is the effect of follicle development on estrogen secretion dulling the follicular phase?
Estrogen levels increase, until around day 12, just before ovulation, where it starts to decrease
During which days of the cycle does the level of estrogen in the blood increase most rapidly? What happens in the uterus during this time?
During days 10-12. In this time, the endometrium in the uterus is thickening
What is the relationship between follicle development and LH levels during Days 10-12? Why is this the case?
Which hormone directly stimulates ovulation?
As the follicle develops, the LH levels increase because LH triggers ovulation, which is the rupturing of the follicle once it’s fully developed (not during days 10-12)
LH. It’s the hormone that is at it’s highest on day 14, which is when ovulation occurs
What event is associated with the decline of LH in the blood?
How does this affect progesterone levels?
What happens in the uterus during this time?
The development of the Corpus Luteum
The CL secretes progesterone,so the levels of it in the blood will increase
If fertilization doesn’t occur, the CL will break down, which will cause proges. levels to decrease which will cause the endo. to double or triple in thickness
If fert. does occur the CL will keep proges. levels high, which will maintain the endo. to support the zygote and later on a embryo
What hormonal changes are associated with the changes in the CL at the end of the luteal phase of the cycle?
What happens in the uterus following these hormonal changes? Why?
As the CL degenerates, FSH & LH levels increase to restart the menstrual cycle again. Estrogen and Progesterone levels decrease
Menstruation will happen, because if the CL disintegrates, progesterone levels will decrease, which breaks down the endometrium
How do increased levels of estrogen and progesterone appear to affect the level of FSH in the blood?
In general, when estro. & proges. levels increase, FSH levels decrease, and vice versa. Except at ovulation
Compare and contrast the functions of estrogen and progesterone on the menstrual cycle
Estrogen & Progesterone inhibit the HP’s release of GnRH. The CL releases estro. & proges. . As the estro. Levels increase, the endo. will thicken, and the high levels will inhibit the release of FSH & LH. They both play a major role in the Luteal phase
Progesterone levels maintain the endometrium, and if fertilization doesn’t occur, the corpus luteum will disintegrate and the progesterone levels will decrease. If it does occur, the CL will keep producing progesterone, so the endometrium can support a zygote
At what time in the menstrual cycle is a woman most fertile?
Around day 14, when ovulation happens, this is because an egg has just been released, so if intercourse happens, the sperm will likely fertilise the ovum
If the levels of estrogen and progesterone were artificially kept at a high level, explain what the effect would be on:
FSH levels
Ovulation
The menstrual cycle
FSH levels would stay low, which would stop follicles from growing, which mean that they couldn’t mature, which would mean that ova wouldn’t develop
Ovulation wouldn’t happen, as higher levels of Estrogen inhibits the release of LH, which triggers ovulation, and FSH which stimulates follicle growth
The menstrual cycle wouldn’t happen. Estrogen & Progesterone inhibit the release of LH & FSH which are needed for the menstrual cycle to BE a cycle. The menstrual cycle is for making a potential zygote, and if estro. & proges. levels were to stay high, ovulation wouldn’t occur, and follicle wouldn’t mature. Which means that eggs wouldn’t get released, & ova wouldn’t develop, respectively
