Here are some quick tips on how to distinguish classic crystal from plain glass. 1  Hold up a glass to the light. 2  If the glass acts as a prism and you see a rainbow you are holding crystal. 3  If not, it is just plain glass. 4  When struck, crystal produces a musical ring. 5  Glass does not.
Hormonal control of menstrual cycle. The ovarian hormones circulate in the blood and are excreted in modified forms in the urine. Estimation of the urinary output by chemical methods gives an indication of the blood levels and of the total production of these substances.
The menstrual cycle involves changes in hormone levels and the shedding of blood. The average length of a menstrual cycle lasts 28 days. Hormones produced during the menstrual cycle, such as estrogen and progesterone, are needed to maintain health. As a result, changes in hormone levels have a great impact on the menstrual cycle. Since hormone production is affected by diet, diet affects the menstrual cycle as well.