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.
Hormones secreted by the hypothalamus, anterior pituitary gland, and ovaries control the principal events. The uterine (menstrual) cycle is a concurrent series of changes in the endometrium of the uterus to prepare it for the arrival of a fertilized ovum that will develop in the uterus until birth.