Menstrual cycle

Question 1

What are the three phases?

Answer 1

Preovulatory, ovulatory, postovulatory

Question 2

How long does the menstrual cycle last?

Answer 2

An average of 28 days

Question 3

When is the first day of menstrual flow in the cycle?

Answer 3

Day 1

Question 4

What happens in the preovulatory phase?

Answer 4

• From days 1-6: mentrual flow/mentruation
• Pituitary gland secrets FSH: stimulates the development of follicles in the ovaries
• Follicle develops. begins to make estrogen: thickens the lining of the uterus (endometrium) with blood and tissue
• When estrogen levels are high: pituitary gland stops making FSH and starts making LH

Question 5

What happens in the ovulatory phase?

Answer 5

The increased amount of LH allows the follicle to break and release the secondary oocyte (ovulation)

Question 6

What happens in the postovulatory phase?

Answer 6

• After the follicle has burst, estrogen levels drop slightly
• The drop in LH causes the follicle to transform into a corpus luteum
• Corpus luteum secretes progesterone and estrogen: thicken lining of uterus, preparing it for a fertilized egg
• High levels of progesterone and estrogen decrease production of FSH and LH
• Fertilization occurs, corpus luteum secretes estrogen and progesterone to keep lining
• No fertilization occurs, corpus luteum breaks down, estrogen and progesterone levels drop, uterus lining is shed during menstruation, new cycle begins