Search Results for 'Book:Muscular system'

The human heart is a muscle, about the size of your fist. Each day, your heart beats around 100,000 times. This continuously pumps five litres of blood around your body through a network of blood vessels, your circulatory system. This delivers oxygen and nutrients to all parts of your body to help your organs and muscles work properly. Your blood also carries away unwanted carbon dioxide and waste products.