Human endocrine system: ovary

The idea

The ovaries are paired endocrine glands in the female reproductive system. As endocrine organs they secrete the hormones oestrogen and progesterone directly into the bloodstream, so they act on distant target tissues rather than through ducts. Oestrogen drives development of female secondary sexual characteristics at puberty and helps regulate the menstrual cycle; progesterone maintains the uterus lining and supports early pregnancy. The ovaries also contain the follicles that release eggs, so they have both an endocrine role and a reproductive role. In exam questions, identify the ovary as the source of oestrogen and progesterone, and link each hormone to its effect, for example oestrogen causing breast development or progesterone maintaining the lining of the uterus.

What earns the marks

• States that the ovaries are endocrine glands that secrete hormones directly into the blood.
• Names oestrogen and progesterone as the main hormones produced by the ovaries.
• Links oestrogen to female secondary sexual characteristics and to regulation of the menstrual cycle.
• Links progesterone to maintenance of the uterus lining and support of early pregnancy.
• Recognises that the ovaries also release eggs, so they have a reproductive role as well as an endocrine role.
• Uses the idea of a target organ or target tissue when explaining how ovarian hormones produce their effects.

Common mistakes and how to put them right

• Writing that the ovaries release hormones through ducts.

  Put it right by stating that endocrine glands are ductless and secrete hormones into the bloodstream.

• Confusing oestrogen with testosterone.

  Put it right by naming oestrogen and progesterone as ovarian hormones and testosterone as the main male sex hormone from the testes.

• Claiming the ovaries produce insulin or adrenaline.

  Put it right by matching each gland to its hormones, for example pancreas to insulin and adrenal glands to adrenaline.

Exam tips

• Read the command word carefully: describe needs linked detail, whereas identify or name needs only the gland or hormone.
• When asked for a hormone, give its name and one clear effect, such as progesterone maintaining the uterus lining.
• Use precise terms such as endocrine gland, bloodstream and target organ rather than vague phrases like 'controls the body'.