Menstrual Cycle

Question 1

Menstrual cycle

Answer 1

This involves the action of the hormones oestrogen, progesterone, LH and FSH

Question 2

Follicle stimulating hormone (FSH)

Answer 2

A cycle begins with the secretion of FSH by the pituitary gland.

FSH is transported around in the blood and causes the follicles in the ovary to start to grow.

Each month approx 20 eggs develop, but only one is usually used.

Question 3

Oestrogen

Answer 3

Causes secondary sexual characteristics

The cells of the growing follicles secrete oestrogen

Oestrogen causes the lining of the uterus to become thicker to prepare for fertilisation

Also causes the production of Luteinising Hormone (LH)

Question 4

LH

Answer 4

Causes the follicles to swell and erupt

The egg is released (called ovulation)

Question 5

Progesterone

Answer 5

After ovulation, the follicle cells in the corpus luteum secrete progesterone.

Progesterone prepares the uterus lining for pregnancy.

If fertilisation does not occur, the released ovum and corpus luteum break down.

The progesterone level decreases and the uterus lining breaks down - menstruation