The familiar sounds of your heart are made by the heart's valves as they open and close.
Did you know?
Giardia is one of the most common intestinal parasites worldwide, and infects up to 20% of the world population, mostly in poorer countries with inadequate sanitation. Infections are most common in children, though chronic Giardia is more common in adults.
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Human kidneys will clean about 1 million gallons of blood in an average lifetime.
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Everyone has one nostril that is larger than the other.
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Autoimmune diseases occur when the immune system destroys its own healthy tissues. When this occurs, white blood cells cannot distinguish between pathogens and normal cells.
