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Drugs are in development that may cure asthma and hay fever once and for all. They target leukotrienes, which are known to cause tightening of the air passages in the lungs and increase mucus productions in nasal passages.
When blood is deoxygenated and flowing back to the heart through the veins, it is dark reddish-blue in color. Blood in the arteries that is oxygenated and flowing out to the body is bright red. Whereas arterial blood comes out in spurts, venous blood flows.
There are approximately 3 million unintended pregnancies in the United States each year.
The familiar sounds of your heart are made by the heart's valves as they open and close.
The heart is located in the center of the chest, with part of it tipped slightly so that it taps against the left side of the chest.