With water, colder and saltier equals denser. At the earth's poles, when water freezes, the salt doesn't necessarily freeze with it, so a large volume of dense cold, salt water is left behind. When this dense water sinks to the ocean floor, more water moves in to replace it, creating a current. The new water also gets cold and sinks, continuing the cycle. Incredibly, this process drives a current of water around the globe.
Medical Definition of HEART DISEASE. : an abnormal organic condition of the heart or of the heart and circulation.See heart disease defined for kids.ADVERTISEMENT.edical Definition of HEART DISEASE. : an abnormal organic condition of the heart or of the heart and circulation.
Heart: The muscle that pumps blood received from veins into arteries throughout the body. ... See the entire definition of Heart. Heart attack: The death of heart muscle due to the loss of blood supply. The loss of bloo... See the entire definition of Heart attack. Heart disease: Any disorder that affects the heart. Sometimes the term heart disease is ... See the entire definition of Heart disease. Heart muscle: A type of muscle with unique features only found in the heart. The heart mus... See the entire definition of Heart muscle