T he heart is the body's hardest-working muscle. Whether you're awake or asleep, or exercising or resting, your heart is always at work. It pumps blood through arteries to deliver oxygen to organs and ...

The human heart: Facts about the body's hardest-working muscle; ... There are arguably some parts of the human body that don't serve any useful purpose, such as the male nipple.

The five vital organs in the human body are the brain, heart, lungs, kidneys, and liver. Other organs include the gallbladder, pancreas, and stomach. Organ systems, such as the nervous system ...

The human body is a wonderous thing, especially when you consider how intricate and efficient each bodily system is. For instance, an adult’s blood vessels could encircle the earth 2.5 times if ...

Microplastics, which are less than 5 millimeters wide — or about the size of a pencil eraser —can enter the human body through the mouth, nose and other body cavities.