Circulatory System


The Circulatory system is located throughout the body.
It pumps blood through the whole body. Blood carrying carbon dioxide will return from body cells entering through the right atrium. When the heart beats it pushes the blood down to the right ventricle. When the heart beats again it pushes the blood to the lungs where the blood flows through capillaries that are touching air sacks in the lungs. The red blood cells release the carbon dioxide and it enters the lungs to be exhaled. Then the oxygen rich blood cells head back to the left side of the heart. Where the blood flows into the left atrium. When the heart beats it squeezes the blood into the left ventricle. When the left ventricle contracts the blood gets pumped through the arteries to the body. Where the red blood cells transport oxygen then it picks up carbon dioxide. This process is repeated over and over.

Major Organs

circulatory system diagram.jpg

System Functions

The hearts function is to pump blood throughout the body and the veins carry the blood back to the heart. Then the arteries carry oxygen rich blood away from the heart. The capillaries connect arteries to the veins. The red blood cells will travel threw the veins while carrying carbon dioxide returning it to the lungs. Meanwhile the white blood cells are standing guard ready to fight off germs when they enter the body. The platelets will also be there to help stop the bleeding. Throughout this whole process plasma is carrying blood cells and other things throughout the body.


Hypertension or high blood pressure is when your blood pressure is consistently higher than the recommended level. If not treated it could cause damage to the heart and blood vessels which can increase the risk of a heart attack and other heart diseases.


  • Nausea and vomiting
  • Headaches
  • Dizziness
  • Blurred vision
  • Chest pain
  • Shortness of breath


To treat high blood pressure you need to remove salt from your diet. Doctors normally recommend dieting but sometimes medication is required.

Staying Healthy

The heart is a muscle and muscles get stronger when they get a work out. So to keep your heart beating and blood flowing you need to exercise. Swimming, running, and biking are just a few examples. Also eating healthy keeps your heart in shape. Foods full of fat are bad for you because the fat can build up and block blood vessels. But fruits and veggies are a much better choice. Whole grains and cereal are also good for you as long as the cereal isn’t full of sugar. Salt is also bad and can give you high cholesterol. But of above all things the best thing you can do for your heart is to NOT SMOKE!!! Smoking is a major cause of heart disease and is definitely one of the worst things you can do to your heart.

Interactions with other body systems
The circulatory system interacts with other body systems in a couple ways. It interacts with the respiratory system because the blood gets oxygen from the respiratory system and the blood drops off carbon dioxide in the lungs which is also part of the respiratory system.

Another way that the circulatory system interacts with other systems is with the digestive system. Because blood flow is needed for the digestive system to digest food. Also nutrients that come from being digested go into the blood stream to be transported wherever the nutrients need to go.

Other Interesting information

  • You have thousands of miles of blood vessels in your body. "Bill Nye the Science Guy" claims that you could wrap your blood vessels around the equator TWICE!
  • One drop of blood contains a half a drop of plasma, 5 MILLION Red Blood Cells, 10 Thousand White Blood Cells and 250 Thousand Platelets.
  • It takes 20 seconds for blood to circulate the entire body. Oxygenated blood leaves the aorta about about 1 mile an hour


The Circulatory System By: Darlene R. Stille 1997 Childrens Press
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