Sexual studies biology assignment 1 Essay Example | Topics and Well Written Essays - 1250 words

Sexual studies biology assignment 1 - Essay Example Hormonal changes The menstrual cycle is determined by the functioning of four organs namely; the hypothalamus, the anterior pituitary gland, the uterus and the ovaries. It consists of phases identified as the follicular, ovarian and luteal. The beginning of the cycle is marked by a decrease in estrogen and progesterone levels. These are primary female hormones. This decrease stimulates the hypothalamus to produce Follicle Stimulating Hormone Release Factor (FSHRF). The FSHRF triggers the anterior pituitary gland to produce Follicle Stimulating Hormone (FSH). FSH is responsible for the release of estrogen in the ovaries which leads to the formation of the Graafian follicles in the cortex of the ovaries. These follicles are cells which cannot be fertilized. Increasing levels of estrogen cause the growth of uterine wall in preparation for possible implantation of the fetus after fertilization. This marks the follicular phase (Ferin, Jewelewicz, and Warren 5). The ovarian phase begins wi th the production of Luteinizing Hormone Releasing Factor (LHRF). This is initiated by the hypothalamus in response to low progesterone levels. LHRF then activates the production of Luteinizing hormone in the anterior pituitary gland. This hormone causes the production of progesterone from the ovaries. ... The luteal phase is characterized by the change of color to yellow of Graafian follicles to form the corpus luteam. The hormone progesterone also called the hormone of pregnancy is identified as responsible for this. The hormone further leads to the thickening of the uterus lining and increased blood supply in readiness for possible fertilization. If fertilization does not occur, progesterone levels start to drop. This decrease and eventual decline causes the shedding of the uterine wall, tearing of blood vessels and ejection of the contents through the vaginal tract. This is menstruation and marks the end of the cycle. The low levels of progesterone and estrogen effectively stimulate the hypothalamus to begin the next cycle (Ferin, Jewelewicz, and Warren 10). Fertile period of the cycle The period of the menstrual cycle when fertilization is most likely is identified as mid way through the cycle. A female whose cycle takes twenty eight days for example would be fertile on the fourte enth day. This is when ovulation takes place. The fertile egg (ovum) has a lifespan of twenty four hours and the fertile period lasts as much. The male sperm however has a longer lifespan of three to five days once released into the female. This means sperms released three to five days before ovulation can fertilize the egg. The twenty four hours immediately after ovulation however remains the most fertile period (Edin, Golanty, and Brown 170). Physical and emotional changes during cycle The hormonal variations during the cycle are identified as the cause of physical and emotional changes over the period. Studies show that contraction of the uterus (cramps) is inevitable. Lower back pain, fatigue and pelvic