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.
Also known as: CVD. Cardiovascular disease (CVD) is a general term used to describe disorders that can affect the heart (cardio) and/or the body's system of blood vessels (vascular).Most cardiovascular diseases reflect chronic conditions â conditions that develop or persist over a long period of time.n addition, there are some risk factors that cannot be controlled, including age, gender, and family history: 1  CVD risk increases with age. 2  Men are generally at higher risk of heart disease; however, women's risk increases to that of men's after menopause.