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