5.3.4 - Hormones in Human Reproduction

What is the function of reproductive hormones during puberty?

• Males: cause the development of secondary sexual characteristics.

• Females: cause the development of secondary sexual characteristics and the maturation of eggs.

What is the main reproductive hormone?

Testosterone, which is produced by the testes and controls sperm production.

What is the main female reproductive hormone?

Oestrogen, which is produced by the ovaries and is involved in the menstrual cycle.

What is the menstrual cycle?

The monthly cycle of physiological changes that occur in females, involving the shedding of the uterus lining (menstruation) and ovulation.

Describe the events of the menstrual cycle.

• Uterus lining thickens and eggs begin to mature in the ovaries.

• An egg is released from one of the ovaries (ovulation) - uterus lining remains thick.

• If the egg is fertilized, pregnancy may occur. If not, both the egg and the uterus lining are shed during menstruation.

What is ovulation?

The release of a mature egg from the ovaries, which occurs approximately every 28 days.

Name the four main hormones involved in the menstrual cycle.

• Oestrogen

• Progesterone

• Follicle stimulating hormone (FSH)

• Luteinizing hormone (LH)

What is the role of FSH in the menstrual cycle?

Secreted by the pituitary gland. It controls the maturation of eggs within the ovaries (inside a follicle) and triggers the production of oestrogen by the ovaries.

What is the role of oestrogen in the menstrual cycle?

• Produced by the ovaries and released due to the action of FSH - it causes the regrowth of the uterus lining.

• It triggers the production of LH and restricts the release of more FSH.

What is the role of LH in the menstrual cycle?

LH is produced in the pituitary gland as a result of oestrogen. Its release triggers ovulation.

What is the role of progesterone in the menstrual cycle?

Secreted from the follicle of the ovary. It sustains the uterus lining and inhibits FSH and LH.