Many steels add to the iron-steel mix other metals that give the entire substance desirable properties such as strength, heat resistance, or flexibility. Steel is considered a mixture rather than a compound because the iron does not chemically bond with the carbon and other components.
Some of estrogen's effects include: 1  Increasing serotonin, and the number of serotonin receptors in the brain. 2  Modifying the production and the effects of endorphins, the feel-good chemicals in the brain. 3  Protecting nerves from damage, and possibly stimulating nerve growth.
An overall increase in heart attacks among women is seen about 10 years after menopause. Heart disease is the leading killer of women. Estrogen Levels May Play a Role. A decline in the natural hormone estrogen may be a factor in heart disease increase among post-menopausal women. Estrogen is believed to have a positive effect on the inner layer of artery wall, helping to keep blood vessels flexible. That means they can relax and expand to accommodate blood flow.