3. The body’s largest organ is the size of six tennis courts, yet is only one cell thick
Image Source: Wikipedia
The smooth lining of more than 60,000 miles of blood vessels, known as the ‘Endothelium’ would cover 6 tennis courts if they were removed from the human body and flattened!
The role of the endothelium is to act as a barrier to control substances that can pass fom the blood into the wall of the arteries. They help regulate blood pressure, fight off disease, control blood clotting and fine-tunes the blood so it flows easily around the body.