How to Tell Crystal From Glass. 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.
Blood pressure is controlled by tiny muscles that line the inside of your blood vessels. These muscles allow your arteries to operate like soft rubber tubes, that expand with each beat of your heart. When these muscles throughout the vascular system [the arteries and veins that carry blood] expand, blood pressure drops.
The kidneys are able to control blood pressure by either reabsorbing water to maintain blood pressure or by allowing more water than usual to be excreted into urine and thus reduce blood volume and pressure. Sodium ions in the body help to manage the bodyâs osmotic pressure by drawing water towards areas of high sodium concentration.