Menstrual Cycle PDF

TOPIC 3 REPRODUCTIVE AND SEXUAL Cycle Day: 1-13: First Part of the Menstrual HEALTH Cycle OUTLINED BY:HUDJAIMA M. MARIWA, RN, MN Menstrual (Cycle days 1-6) Menstru...

TOPIC 3 REPRODUCTIVE AND SEXUAL Cycle Day: 1-13: First Part of the Menstrual HEALTH Cycle OUTLINED BY:HUDJAIMA M. MARIWA, RN, MN Menstrual (Cycle days 1-6) Menstrual Cycle Follicular Phase (Cycle days 7-13) Purpose of the Menstrual Cycle: is to release Proliferative Phase (Cycle days an egg for potential fertilization (from the ovary) 7-14) so it can implant into the endometrium…hence help develop a baby. If this doesn’t happen, the 28 day cycle starts all over (note cycle days MENSTRUAL Phase: (uterine changes…cycle vary among women). days 1-6) Two structures that play a vital role in the Goal: shed the stratum functionalis layer of the woman’s reproductive cycle: endometrium Ovary & Uterus (they work together) Woman has bleeding (consists of 1-6 days) where she is shedding the stratum functionalis (functional layer) of the endometrium. If Each structure has three cycles (and pregnancy did not occur during the last cycle, these cycles correspond with each the progesterone and estrogen levels drop other) which causes the layer to shed. During this same time, there are OVARY Ovarian Cycles: Follicular (occurs during the CHANGES known as the: menstrual and proliferative phase), Ovulation, Luteal Phase FOLLICULAR PHASE: (ovarian changes…..cycle days 1-13) Uterine Cycles: Menstrual & Proliferative (both occur during the follicular phase), Secretory Goal: prepare a follicle to release a mature egg Phase (ovum) Easy Recap of these Phases: How does it do this? When hormone levels from the previous cycle drop (specifically 1. Follicular Phase (cycle day 1-13…ovarian progesterone and estrogen) the hypothalamus changes) happens during Menstrual (cycle releases Gonadotropin-Releasing Hormone days 1-6…uterine changes) & Proliferative (GnRH) and this causes the anterior pituitary Phase (cycle days 7-14….uterine changes) gland to release FSH (follicle stimulating hormone) and LH (luteinizing hormone). 2. Ovulation (day 14…the midpoint of the 28 day cycle) The FSH released from the anterior pituitary gland stimulates the follicles in the ovary to 3. Luteal Phase (cycle days 15-28….ovarian grow. A woman has two ovaries (right and left) changes) happens during Secretory Phase and each contains MANY follicles. (cycle days 15-28….uterine changes) Follicles are fluid-filled sacs in the ovary that *Typical menstrual cycle is 28 days contain an immature egg known as an oocyte. NOTE: FSH will cause several follicles to develop but only ONE turns into a Graafian *The last 5 days of the follicular phase and follicle (mature follicle) that will release a during ovulation is the most fertile time for a mature egg (ovum). The other follicles that didn’t woman to get pregnant…sperm live release an egg will die. approximately 5 days and the egg lives for 24 hours (so fertile cycle days would be days 9 As the follicle matures, it will produce hormones -16). such as ESTROGEN. The estrogen will steadily increase as the egg reaches maturity. There will PROLIFERATIVE Phase (uterine be a small dip in the production of FSH and LH changes…cycle days 7-14) because the body senses the extra estrogen which represents that the egg must be mature Goal: to rebuild the stratum functionalis layer and the follicle doen’t need to be stimulated to that was just shed during the menstrual phase grow. This is the negative feedback loop where (in case the ovum is fertilized) so it can implant the estrogen will signal to the hypothalamus to into the uterus. decrease production of GnRH so the anterior pituitary gland will quit releasing so much FSH What causes the layer to rebuild? Remember and LH. how during the follicular phase the maturing follicles are secreting estrogen? The estrogen However, the mature follicle is producing from the secretion of the maturing follicles is massive amounts of estrogen and the estrogen ALSO causing the stratum functionalis layer to secretion from the follicle will peak to a VERY rebuild. In addition, it causes cervical mucous to HIGH POINT. This will actually cause the thin which allows sperm to migrate easier to the anterior pituitary gland to release a surge of LH egg. (luteinizing hormone)…hence positive feedback loop and this is what is called an LH surge OVULATION: Cycle day 14 (cycle day 11-13). The egg is released from the ovary. The ovum LH plays a huge role in causing the egg to be enters into the PERITONEAL CAVITY. It makes released from the follicle (which causes it journey to the fallopian tube with the help of ovulation to happen). LH causes the egg to the fimbria which have cilia to help sweep the mature and breaks down the wall of the Graafian ovum into the fallopian tube. If sperm are follicle allowing the follicle to release the egg present to fertilize the egg, fertilization will occur which is now called an ovum. 24-36 hours after in the fallopian tube most likely in the the LH surge the ovary will release the ovum AMPULLA. (usually happens mid-cycle…hence day 14). The egg will only live for 24 hours and In addition, LH helps the Graaifan follicle that disintegrate, if not fertilized. The woman will released the egg turn into the CORPUS have a low basal body temperature before LUTEUM. The corpus luteum will be responsible ovulation and then increase 0.4-1’F around for releasing progesterone and estrogen to ovulation. maintain a potential pregnancy until the placenta can take over. NOTE: the development of the Cycle Days 15-28: Second Part of the corpus luteum occurs in the LUTEAL Menstrual Cycle Phase…note why it is called LUTEAL…the LUTE of luteal corresponds with the word Luteal (cycle days 15-28) corpus LUTEum). Secretory (cycle days 15-28) LUTEAL PHASE (ovary changes….cycle day However, if fertilization occurs the fetus will start 15-28) to produce HcG Human chorionic gonadotropin (hence what a pregnancy test Goal: prepare the endometrium for a potential picks up) and this will prevent the corpus luteum fertilized egg from dying. So, until the placenta becomes fully functional, the corpus luteum will help maintain Begins when the egg is releases from the ovary. steady levels of progesterone and estrogen to maintain the endometrium for the fetus. The The corpus luteum forms which developed from placenta will take over will progesterone and the Graaifan follicle that released the ovum. The estrogen production at approximately 8 weeks. corpus luteum acts as a temporary endocrine structure that secretes SECRETORY Phase: (uterine changes….cycle progesterone and estrogen. Progesterone days 15-28) prepares the endometrium for implantation of the embryo, if the ovum is fertilized. Goal: endometrium is receptive to the implantation of a fertilized ovum Role of Progesterone: The progesterone being released from the stimulates estrogen production corpus luteum is allowing the endometrium to be allows the endometrium to receptive for implantation of the fertilized ovum. receive the fertilized ovum for implantation stops production of LH and FSH (so possible pregnancy can be maintained) and estrogen inhibits the hypothalamus from releasing GnRH (hence new reproductive cycle….if the ovum is fertilize you want to prevent another menstrual cycle from occuring so pregnancy can occur). This will help prevent the hypothalamus from releasing GnRH which will prevent LH and FSH from being secreted in case fertilization has occurred. Corpus luteum stays in place for about 14 days and if fertilization hasn’t occurred it disintegrates. It will turn into the corpus albicans. When the corpus luteum dies, estrogen and progesterone will decrease and this leads to a new reproductive cycle….the hypothalamus will release GnRH which will cause the anterior pituitary gland to release FSH and LH and the woman will shed the uterine lining and new follicle will be stimulated to produce a new egg etc.