When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. The circulatory system consists of three independent systems that work together: the heart ...

Take a deep breath — here's how the respiratory system works. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. The human respiratory system is a ...

What Is the Respiratory System? The respiratory system is the organs and other parts of your body involved in breathing, when you exchange oxygen and carbon dioxide. All the cells in your body need ...

The metabolic activity of any tissue is limited by its blood supply; the more active any organ, the more blood it needs and the more extensive its vascularization. The changes in metabolic activity ...

Your circulatory system works all day, every day, to pump oxygen throughout your body. There are cardiovascular conditions that can impact this system. Your circulatory system, also known as your ...

Veins are a type of blood vessel that return deoxygenated blood from your organs back to your heart. These are different from your arteries, which deliver oxygenated blood from your heart to the rest ...

You remember how Dorothy, Toto, and the rest of the gang were trying to make their way to see the Wizard of Oz? That’s kind of how veins work in relation to your heart. Your heart is the wizard, and ...

Your heart is an amazing organ. It continuously pumps oxygen and nutrient-rich blood throughout your body to sustain life. This fist-sized powerhouse beats (expands and contracts) 100,000 times per ...