Menstual Cycle Essay Example | Topics and Well Written Essays - 250 words

Menstual Cycle - Essay Example Ovarian cycle is dependent on two of the three gonadotropic hormones that are produced by the anterior pituitary gland. These hormones include follicle stimulating hormone (FSH) and luteinizing hormone (LH). The follicular phase is controlled by the FSH, which includes days 1 to 14, and the luteal phase is controlled by LH, which includes days 15 to 28 of a 28 day (normal) cycle. At the commencement of each menstrual cycle, FSH stimulates follicle development. This result to estrogen production, causing maturation of the ovum contained within the follicle. Oestrogen levels increase as the follicle grows; this high level of oestrogen triggers the pituitary gland to release a surge of LH. This is a positive feedback effect as the levels of oestrogen will be high; causing the muscle and uterine lining layers to be thicker in anticipation of an embryo. This abrupt increase of LH results to the follicle bursting open. This act releases the mature ovum into the abdominal cavity. This proce ss (ovulation) takes place on day 14; the floating ovum is then drawn towards the fallopian tube and travels to the uterus (Ricci & Kyle, 2009). After ovulation, LH levels remain increased and cause the fragments of the follicle to develop into the corpus luteum. Corpus luteum secretes progesterone hormone. The work of progesterone is to maintain the uterus lining. If fertilization fails to take place, then, the corpus luteum disintegrates and the levels of oestrogen and progesterone drop. This drop is triggered by a negative feedback effect on the pituitary due to the combination of oestrogen and progesterone; causing the uterine lining to shrink menstruation commences. This marks the start of another of the follicular phase; which is again day one of the cycle (Rosdahl & Kowalski, 2008). In conclusion, if fertilization occurs, then the negative feedback effect on the pituitary will not be experienced as progesterone level will be produced