Explore how your immune system’s vast network of cells, tissues, and organs coordinate your body’s defenses against bacteria, viruses and toxins. — The immune system is a vast network of cells, tissues, and organs that coordinate your body’s defenses against…

View full lesson: The biggest kidney stone on record weighed more than a kilogram and was 17 centimeters in diameter. The patient didn’t actually swallow a stone the size of a coconut; kidney stones form inside the body. So how…

View full lesson: Your body produces more than a liter of mucus every day, and when you’re sick, it can be hard to miss. But what exactly is mucus? And what does it do, besides making you miserable? Katharina Ribbeck…