The ovary is the female reproductive organ that produces eggs and secretes hormones. Follicles are found in the ovaries. After puberty, each woman has about 300,000-400,000 follicles, which are called primordial follicles. After puberty, under the action of estrogen and progesterone secreted by the ovaries, the follicles will gradually increase in size, and will develop and grow up to 18mm or more, which are called mature follicles. Mature follicles produce eggs and are capable of fertilization, so ovaries and follicles are completely different concepts. The ovary is a female gonadal organ that plays a very important role in a woman’s life. It secretes hormones that promote the development of the female reproductive organs and maintain the normal shape of the female body.