
Blood in Your Veins Is Not Blue — Here's Why It's Always Red
Sometimes blood can look blue through our skin. But this is an optical illusion.
Inside your body there’s a bustling highway with your beating heart at the center. Learn all about your body’s 60,000 miles of microscopic blood vessels, 5 to 6 quarts of blood, and the sundry passengers (lymph, blood cells, nutrients and more) that ride it every day.
Related Topics: Respiratory System, Immune System, Lymphatic System, Nervous System