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 disease is any condition that keeps your heart from functioning at its best or causes a deterioration of the heart's arteries and vessels. Coronary heart disease (CHD), also known as coronary artery disease, is the most common form of heart disease, affecting 12.6 million people in America. If you are diagnosed with CHD, it means you have atherosclerosis, or hardening of the arteries on the heart's surface.