The gonad is the organ responsible for producing gametes. The gonads in males are known as the testes, and the gonads found in the females are known as OVARIES. These gonads secrete sex hormones. The hormones produced by these organs play important roles in the development of sexual characteristics.
In the female, two main classes of sex hormones, secreted by the ovaries, affect sexual characteristics: Estrogen and Progesterone.
Estrogen are steroid hormones that support the maturation of the oocytes and stimulate the growth of the lining of the uterus. The secondary sexual characteristics exhibited by female during puberty is brought about by Estrogen. Three Estrogens are found in the circulation:
1. Estrone (E1)- this is the only hormone found in menopausal and post-menopausal women. Estrone is also the least abundant of the three estrogens.
2. Estradiol (E2)- this is the most abundant Estrogen. It serves as the growth hormone for the tissues in the reproductive organ. It is the dominant hormone prior to ovulation. Estradiol is also responsible for the breast development, the changes in the body shape, fat distribution in hips and legs which are commonly seen during puberty.
3. Estriol (E3)- this estrogen is found in significant amount during pregnancy. Estriol can be used to evaluate fetal health as it can be measured through the mother's blood or urine.
Progesterone, on the other hand, is also another steroid hormone that is involved in the menstrual cycle of females and is also significant during pregnancy. It has several important functions, including the following:
- It prepares the uterus for the arrival of a developing embryo, in case fertilization occurs.
- it accelerates the movement of the oocyte or embryo to the uterus.
- It causes enlargement of the mammary glands, working in combination with other hormones, such as estradiol, growth hormone, and prolactin.
I have also found a video explaining what the hormones of the ovary do to our body.