Ovulation and Menstruation

Function of Menstrual Cycle Uterine walls thickens with rich blood supply in preparation for a fertilized egg If fertilization does not occur the walls break down and the cycle repeats again

Stages of Menstruation Stage 1 – Follicular Phase Stage 2 – Ovulation Stage 3 – Luteal Phase Stage 4 – Menstruation

Follicular Phase Pituitary gland in the brain released two hormones – Follicle stimulating hormone (FSH) – Luteinizing hormone (LH) Follicle in ovary begins to develop and release estrogen Increased estrogen levels stimulates lining of uterus to thicken

Ovulation High level of estrogen causes pituitary gland to release a rush of LH When LH level peaks it causes the follicle to rupture and release an egg cell

Luteal Phase Broken follicle forms a yellow colored structure called the corpus luteum Corpus luteum releases the hormones estrogen and progesterone that helps to stimulate further growth of the uterine lining

Menstruation If an egg is not fertilized the corpus luteum breaks down Less estrogen and progesterone is released and the lining of the uterus breaks down Low levels of estrogen stimulate the release of FSH and LH from the pituitary gland and the cycle begins again