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.
Cardiovascular disease terms. Cardiovascular disease (CVD) is a broad term for a range of diseases affecting the heart and blood vessels. A heart attack or stroke may be the first warning of an underlying disease.erebrovascular disease (stroke). A stroke is the brain equivalent of a heart attack and is where blood flow to the brain is blocked or interrupted. The affected part of the brain is then deprived of oxygen and nutrients leading to cell death.