The cardiovascular system carries oxygen and nutrients to all of the cells in the body. It also picks up carbon dioxide and other waste products that the body produces so that they can be disposed of. The main components of this system are the heart, blood vessels, and blood. When a problem arises within the system, it is known as a cardiovascular disease.
For thousands of years, people have been fascinated by the cardiovascular system. This probably has a lot to do with the fact that for humans and other animals, life is associated with a beating heart. During ancient times, people had a general idea about the cardiovascular system. However, it was not until the 17th century that William Harvey showed that the cardiovascular system formed a closed loop in which blood is pumped by the heart. As would later be discovered, the purpose of the cardiovascular system is to:
- Carry oxygen and nutrients to all of the cells in the body
- Pick up carbon dioxide and other waste products that the body produces so that they can be disposed of.
As would also be discovered, three important components of the cardiovascular system include the heart, blood vessels, and blood. (The fourth part, not discussed in this article, includes certain nerves and hormones that act as control systems to make sure the cardiovascular system works properly.)
The human heart is a hollow, muscular organ about the size of a fist. Its job is to pump blood through a network of blood vessels. These vessels form a loop, which starts at the heart, goes out through your body, and then ends back at the heart again.
When talking about the heart, it is helpful to look at its components:
- Heart valves
- Blood vessels, including the arteries and veins
- Electrical system.
The inside of a normal heart is divided into four chambers:
- The right atrium
- The left atrium
- The right ventricle
- The left ventricle.
Valves of the Heart
In a healthy heart, there are valves that keep blood flowing in a one-way direction. When they open, they only let the right amount of blood through, and then they close to keep blood from flowing backwards in between beats.
The circulatory loop begins with blood entering the right atrium of the heart. When the heart beats, blood flows from the right atrium into the right ventricle through a valve.
From the right ventricle, blood flows through another valve and then to the lungs, where it picks up oxygen. From the lungs, it flows back into the left atrium of the heart and through the mitral valve into the left ventricle. From the left ventricle, blood is pumped through the aortic valve and into the aorta, where it goes out to the rest of the body, bringing oxygen and nutrients to your cells.
For the human heart to work right, each of the four chambers must contract, or squeeze, at just the right time. Your heart has an electrical system that helps coordinate this timing.