Menstrual Cycle

Module 14 Lesson 1 Assignment 1

Hormones: LH

The pituitary gland release the LH hormone under the effect of GnRH. Depending on the levels of estrogen and progesterone in the blood, more LH could be released. At the beginning of the menstrual cycle, LH starts low, then gets higher, then shifts slightly down again, but surges up just before day 14. This surge is what triggers ovulation.

Hormones: FSH

The FSH hormone is very similar to the LH hormone and undergoes just about the same process that LH undergoes. FSH is released from the pituitary gland and more can be released due to the levels of progesterone and estrogen in the blood. FSH's pathway it undergoes is that is starts low, gets higher, drifts slightly down, then reaching its peak and gradually falls down.

Hormones: Estrogen

The eggs, during their maturation, release the estrogen hormones. The pathway estrogen takes is very different from what LH and FSH take. The curves concerning estrogen continuously go up and down, due to the changes of the estrogen levels and what happens in the ovaries. The two depend on one another.

Hormones: Progesterone

The eggs, during their maturation, also release progesterone hormones. They are very similar to estrogen because their curves are also continuously going up and down due to what is occurring in the ovaries, affecting the progesterone levels.

Endometrial Lining & Hormones

In the lining of the uterus, under the influence of estrogen, it gets thicker before ovulation. After that, its gland begins to secrete nutrients. The endometrial lining during the menstrual cycle increases from .4-.6 inches in thickness to .2-.3 inches.

Follicular Development Based On Hormones

In the beginning of this cycle, a cluster of ovarian follicles begin to grow at the start of the cycle, but only one egg reaches full maturity. At the start of the cycle, the increasing levels of FSH bring about the maturation of the ovarian follicle. These follicular cells, in return, produce increasing levels of estrogen.

How does pregnancy change hormones?

The first hormone that will begin working is the hCG, which will help to produce estrogen and progesterone in the first 10 weeks of conception, until the placental cells can do it themselves. Progesterone quiets the uterine muscle so that the fertilized egg can have a safe landing while implanting. Estrogen changes your mood and sex drive, while also stimulating the growth of your uterus and the blood flow between the uterus and placenta. Relaxin works to relax the intrauterine ligaments. Oxytocin is the feel-good hormone that helps us bond with others. All of these hormones affect your mind and body during pregnancy.

How does the endometrial lining change during pregnancy?

Due to the influence of estrogen, it gets thicker in the lining before ovulation. After that, its glands will secrete nutrients. All of this occurs to get your body ready for pregnancy. When pregnancy occurs, gonadal hormones will gradually increase. As a result, the lining of the uterus will not slough off and be rather active.

More pictures of the hormones and their levels through the menstrual cycle