Human Body Quiz: Human Body Systems & Organs

66% of the human body is water.

Your thumb is the same length as your nose. Try it and find out if it's true.

According to the U.S. population clock on December 1, 2010, the U.S. Census Bureau says there are 310,828,459 people in America right now!

Humans sneeze at the rate of about 100 miles per hour, and a cough at about 60 miles per hour.

The living part of the hair is the very bottom part surrounding the papilla, called the bulb. The cells of the bulb divide every 23 to 72 hours, remarkably faster than any other cell in the body

The smallest bone in the human body is about the size of a grain of rice. This bone is called the stapes bone.

The smallest bones in the human body are found in the ears. There are three tiny bones that are found in your middle ear named the malleus, incus, and stapes.

Every 12 years, we humans have an entirely new skeleton due to the body's continual replacement of its bone cells.

The stapedius muscle is the smallest muscle in the body. This muscle, 6.3 mm in length, helps move the stapes bone in the middle ear.

The word "pain" comes from the Latin word "poena" that means punishment or penalty.

A layer of very fine calcium crystals is among the structures in the inner ear that help to regulate balance. Balance is a choreographed arrangement that takes sensory information from a variety of organs and integrates it to tell the body where it is in related to gravity and the earth.

Sweat itself has no odor, but when combined with bacteria and contained in a dark and moist environment, like an armpit, it gives the bacteria a power boost. The medical term for body odor is bromhidrosis.

A pair of human feet contains 250,000 sweat glands. Each foot can sweat the equivalent of half a glass of water per day. There are about one trillion bacteria on each of your feet. That's why feet can smell bad.

There are 9,000 taste buds on the tongue. We lose a lot of these taste buds as we age.

Your skin is the largest organ on your body. On average, your skin weighs about six pounds, and its job is to protect you from infections and germs. Throughout your life, your skin will change constantly, and will regenerate itself approximately every 27 days.