Unit 8: The reproductive system                                                1   2   3

3.2. Female reproductive cycles

The female reproductive cycle lasts 28 days and involves periodic changes in the sex organs. These changes are caused by hormones produced by the hypophysis and the ovaries. Changes occur simultaneously in the ovaries and in the uterus.

- Ovarian cycle. Set of changes in the ovaries are caused by hypophysis hormones, FSH (follicle stimulating hormone) and LH (luteinising hormone).

- Uterine or menstrual cycle. Set of changes in the endometrium of the uterus are caused by oestrogens and progesterone produced by the ovaries.

a) The ovarian cycle

It involves three stages:

b) The uterine cycle

It refers to all the periodical changes that take place in woman’s sex organs. The aim of the cycle is to prepare the uterus for implantation of an embryo if the ovum is fertilized.

This cycle involves three stages.

- Menstrual phase or period. It is caused by the sharp decrease in the amount of hormones produced by the ovaries. As a result, the mucosa of the uterus which is now very thick and highly vascularised is shed and expelled from the body via vagina along with haemorrhage. This phase usually lasts between 4 and 5 days.

- Proliferative phase. The uterine lining is rebuilt thanks to the oestrogens produced by the ovaries. This phase lasts about 11 days.

- Secretory phase. The uterine lining reaches its maximum thickness and gets ready to receive the fertilised ovum. This phase takes place as a result of the progesterone released by the corpus luteum. It lasts around 12 days, until the hormone stop being produced. If fertilisation has taken place, the corpus luteum continues to secrete progesterone and the uterine lining is not shed.

3.2. The following sentences are wrong. Correct them.

a. When ovum is released to the Fallopian tube, the vagina mucosa is fully formed.

b. Follicular phase is caused by the release of progesterone in pituitary gland.

c. Menstruation begins when the hormones produced by the ovary start to produce.

d. The remains of the Graffian follicle (corpus luteum) produce oestrogens.

3.3. Listen and relate each sentence with the correspondent phase

       of the ovarian cycle.

3.4. Listen and relate each sentence with the correspondent phase

       of the uterine cycle.