Describe what is happening during the female monthly cycle related to:
a. fsh, lh, estrogens, and progesterones
b. the follicles in the ovaries
c. the lining of the uterus

All women have to go through what is known as the menstrual cycle. This process allows a woman to be able to prepare for, and conceive, a baby, and carry him/her to full term. As such, there are a series of steps that the female body takes, both physically and physiologically, spurred by the rise and fall of hormones, to ensure the smoothness of the process and the possibility of conception.

The cycle is divided into 4 stages: the menstrual, the follicular, the ovulating, and the luteal stage. Each of them has a play of hormones that will play their part in helping the process be successful. These hormones are: FSH (Follicle Stimulating Hormone released by the Pituitary gland), LH (Luteinizing Hormone, also released by the Pituitary), estrogens, progesterone, and in the case of a pregnancy, hCG (Human Chorionic Gonadotropin, or the pregnancy hormone).

So, as to the question, the play of hormones, and how the cycle develops, would be like this:

1. Menstruation phase: After the late released egg is not fertilized during its timeframe of 24 hours, estrogen and progesterone levels drop, producing reactions in the body: the egg is sheded, the uterine wall lining is shedded, and blood, tissue and mucus comes out.

2. Follicular phase: Almost overlapping, the hypothalamus orders the Pituitary gland to start releasing FSH. This hormone will stimulate the ovaries to begin producing follicles, where the immature eggs are. Around 5 to 20 of them will begin getting matured for release. Only one, in rare ocassions 2, will end the process; the rest, will be reabsorbed by the ovaries. The follicle starts to release estrogens and progesterones that will signal the uterus to begin building up the walls with a lining rich in nutrients, in case of pregnancy.

3. Ovulating, or ovulation phase: As the maturation of the egg continues, the follicles get ready to release it into the fallopian tubes. As this happens, the Pituitary, stimulated by the rising levels of estrogens and progesterones, and by the work of the hypothalamus, releases LH, which will play a part not only in the final maturation of the egg, and the lining, but also in maintaining the levels of estrogen and progesterone so that a pregnancy is successful. At this point, the egg is released by the follicle and the process down the tube begins towards the uterus. It is here that pregnancy can take place.

4. Luteal phase: The follicle that releases the egg, becomes later on the corpus luteum, which will further produce estrogen and especially progesterone, to maintain the lining once the fertilized egg has implanted. If not, it will be reabsorbed and the declining levels of hormones will signal the body to initiate the menstrual phase.

b - the respond is innate and varies over time.

good luck!