Kids' Corner/Parents' Place

Sail the Circulatory System

You are the captain of the USS Heme (short for Hemoglobin, the molecule in the blood that carries oxygen). With your heart pumping away, your job is to carry oxygen in the blood from the lungs to the organs in your body to keep yourself alive. If you don't do your job fast enough, you will die (Game Over). Your fast ship has four transport bins which enable you to move four oxygen molecules from the lungs through the circulatory system to the brain or muscles. At the brain or muscles, you pick up carbon dioxide and transport it back to the lungs. But be careful - poisonous carbon monoxide molecules are invading your lungs from the outside air. Once carbon monoxide attaches to your ship, you form the dreaded carboxyhemoglobin that will not let go. As a result, your ship will have fewer transport bins available and you begin to suffer from lack of oxygen.


  • Your USS Heme starts in the lungs. You must pick up four red oxygen molecules by bumping into them. Hemoglobin can carry only four molecules at a time. You must move as fast as you can through the circulatory system to carry the oxygen to your brain or muscles and avoid running out of oxygen (Life Meter) and dying (Game Over).
  • You can move in any direction using the arrow keys on your keyboard. You can push down two arrow keys at the same time to move in a diagonal direction.
  • After you pick up your oxygen, you must move through the pulmonary veins, travel to the left atrium of the heart, pass through a one-way valve into the left ventricle of the heart, enter the aorta and then travel through the arteries to the organs. You can see your location in the circulatory system on the map at the right side of the activity.
  • At the brain or muscles, you drop off your oxygen and pick up carbon dioxide that is building up in order to transport it back to your lungs. You can choose one or the other organ. Remember to feed both organs if you make more than one trip. You don't want one organ to die from lack of oxygen.
  • After picking up blue carbon dioxide molecules in the brain or muscles, you travel back through the veins to the right atrium, move through a one-way valve to the right ventricle and finally back through the pulmonary artery to the lungs. This begins the cycle all over. Your "Life" meter tells you to hurry and carry more oxygen to the organs. If not, you run out of oxygen and die (Game Over).
  • As the game progresses, gray poisonous carbon monoxide molecules suddenly appear in the lungs. If you bump into them, you form carboxyhemoglobin. This happens when the carbon monoxide molecule attaches itself to your USS Heme ship, taking up one of your transport bins. Each time you form another carboxyhemoglobin, you can carry one less oxygen molecule to your organs. As the percent of carboxyhemoglobin increases on the Toxins meter, you begin to experience terrible health effects. As time goes on, more and more carbon monoxide molecules enter your body and you must work harder to save your life.

Learning Objectives:

At the end of this activity, students and parents will:

  1. Draw a diagram of the circulatory system;
  2. Describe how oxygen is transported and utilized in the body;
  3. Explain how carbon monoxide affects the body;
  4. Explain the relationship between exposure concentration (carbon monoxide concentration in air/percent carboxyhemoglobin in blood) and health effects; and
  5. Describe common symptoms of carbon monoxide poisoning and oxygen deficiency.
Click on the "Go to the Activity" button to start sailing the circulatory system.              

The Center for School and Community Health Education (CSCHE) is an outreach component of the University of Medicine and Dentistry of New Jersey-School of Public Health (UMDNJ-SPH) and the National Institute of Environmental Health Sciences (NIEHS) Center of Excellence at the Environmental and Occupational Health Sciences Institute (EOHSI). UMDNJ-SPH is sponsored by UMDNJ in cooperation with Rutgers, The State University of New Jersey and the New Jersey Institute of Technology and in collaboration with the Public Health Research Institute. EOHSI is jointly sponsored by UMDNJ-Robert Wood Johnson Medical School and Rutgers, The State University of New Jersey.