Take a moment and lay your hand over your heart. Do you feel that steady lubdub rhythm? Your heart is an incredible organ, beating between 60 and 100 times a minute for your entire life and keeping the blood flowing throughout your entire body.  This process is called circulation and the circulatory system is the reason this amazing phenomenon happens!

What is the Circulatory System?

The circulatory system is both simple and very complicated! It is made up of your heart as well as all the blood vessels in your body – arteries, veins, capillaries, and venules. There are three main purposes of the circulatory system:

  1. To carry blood throughout the body and to bring oxygen and nutrients to the cells while picking up cellular waste.
  2. To stop the leakage of blood if you are cut or otherwise injured.
  3. To protect the body by helping to kill off bacteria and other germs which cause illness or infection.

The Flow of Blood through the Circulatory System

To understand the circulatory system better, let’s follow the flow of blood through the heart and the rest of the body.  Picture it as sort of a figure eight, with the blood flowing between the pulmonary and system loops.

The journey begins when deoxygenated blood in the superior and inferior vena cava (two HUGE veins!) enters the right atrium (upper chamber) of the heart. The blood is pushed into the right ventricle of the heart through the tricuspid valve.  From the right ventricle, blood is then pushed into the pulmonary vein and flows to the lungs, where it becomes saturated with oxygen.  Once this happens, it travels back to the heart via the pulmonary artery and enters into the left atrium.  It flows into the left ventricle through the mitral valve. This loop from the heart to the lungs and back again is called the pulmonary loop.

The systemic loop begins when oxygenated blood is pushed out of the left ventricle and into the aorta, the biggest artery in your entire body!  From the aorta, many smaller arteries branch off, all headed for different parts of the body.  The blood flows through these arteries, delivering oxygen and nutrients and picking up cellular waste.  As the blood travels on, the arteries branch off and get smaller and smaller, finally turning into capillaries.  The blood travels through them as well and at one point they become venules, which then turn into veins that will carry the deoxygenated blood back to the right atrium of the heart and finish the system loop.

It is important to note that while it travels around the body, the blood passes through the kidneys many, many times a day.  As it does so, the kidneys remove waste products that the blood has gathered from other parts of the body.  Your body then eliminates these waste products through the urinary tract when you go to the bathroom!

Problems with the Circulatory System

Unfortunately, there are many problems that can crop up in the circulatory system of a child or adult. These can include:

  • Heart defects such as holes in the wall of the heart, heart valves that do not open or close at the right time or a heart that is underdeveloped and not strong enough to pump blood properly.
  • High blood pressure, which means that the blood is pumping with too much force through the vessels; this can lead to long-term damage to the veins.
  • Heart infections, where bacteria or viruses can invade the heart and inflame it. This can take a long time to heal!
  • Atherosclerosis, a disease where cholesterol, a substance that looks a bit like wax, builds up in the arteries and can eventually cut off blood flow to the heart.
  • Hemophilia, where there are not enough platelets in the blood to stop blood flow from a cut or other injury.
  • Leukemia, a kind of cancer that leads to having too many white blood cells.

Keeping the Circulatory System Happy

Some of those diseases sound pretty scary. But the good news is, that many of them can be prevented!  Do you want to keep your circulatory system happy? Here are some ways to do that!

  • Eat healthy! Skip the French fries and pig out instead on fresh fruits and vegetables, whole grain breads and pastas, beans, nuts (if you’re not allergic!) and lean meats, eggs and dairy!  This will give you the nutrients you need to keep your heart strong and your blood vessels healthy.
  • Hydrate! Yes, soda and juice taste good, but what you need is water – and lots of it!  Blood is mostly water – and if you are dehydrated, the flow of the blood can be sluggish and your body is not as efficient at delivering oxygen and getting rid of waste. This can make you feel really crummy – and also make your system work harder than it needs to!
  • Go out and Play! Whether at school or at home, stay active and make sure you go outside and play every day!  Run around at recess.  Take your dog for a walk in the morning. Go to the park with your mom after school.  All this moving about keeps your heart nice and strong!
  • Relax! Between homework, studying for tests and having to clean your room all the time, life can get stressful sometimes!  If you are feeling anxious or stressed out, talk to your parents, your teacher or someone that you trust. They can help you with your problem and make you feel more relaxed. This is important, because feeling stressed out is actually hard on your heart!
  • Don’t stay up too late! When mom and dad tell you to go to bed, don’t try to sneak a computer game up to your room! Getting enough sleep not only helps your growing body, it helps your heart in particular and just plain makes you feel better in the morning!

The takeaway here is that your circulatory system is an amazing set of organs that, every single moment of your life, is working away to keep your body healthy and happy! So take care of it – and it will take care of you!