Template:Aquatic layer topics. An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3000 and 6000 m. Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth âs surface.
Murad discovered in 1977 that nitroglycerin and related artery-widening compounds act by releasing nitric oxide. Furchgott later concluded that cells in the inner lining of blood vessels secrete some unknown substance that makes vessels dilate.
Sex, Nitric Oxide, and the Endothelium. Nitric oxide is made by the blood vesselsâ lining, or endothelium. The endothelium is exquisitely sensitive to the physical and chemical conditions inside our blood vessels. When the endothelium senses heart-healthy conditions, such as physical activity and low cholesterol, it releases more nitric oxide. And thatâs a very good thing. Nitric oxide expands the blood vessels, increasing blood flow and decreasing plaque growth and blood clotting.