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.
This center is located just above the brain stem and secretes hormones that help regulate body temperature. It is this part of your body that orchestrates the many functions that help to control body temperature. All of the autonomic responses of our bodies are controlled by the hypothalamus. It processes the sensory input that the body receives and passes it to the correct area of the brain and body for action. It is this part of your brain that allows you to feel both hot and cold.