O₂ CO₂ SKIT

Key Questions

• What is the path blood flows in the body?
• What is the role of blood as it circulates?

Materials

• poster or diagram of the circulatory system
• red plastic disposable plates, 9-12" in diameter, one for each student
• white foam discs (to represent oxygen)
• blue foam discs (to represent carbon dioxide)
• labels or name tags with the following parts of the circulatory system:
  • superior vena cava
  • right atrium
  • right ventricle
  • pulmonary artery
  • the lungs (2 labels)
  • pulmonary veins
  • left atrium
  • left ventricle
  • aorta
  • artery*
  • capillary*
  • vein*
  • body cell (2 labels, minimum)*
  * Multiple labels should be made for these parts so that each student has a role.

Procedure

1. Distribute the labels, one to each student in the class. Students wear the labels.

2. Have the students arrange themselves in a circle, according to their label, in an order that represents the flow of blood through the circulatory system. Refer to posters and diagrams as necessary.

3. Give the white foam discs (representing oxygen) to the students representing the lungs. Give the blue foam discs (representing carbon dioxide) to the students representing the body cells.

4. Talk through the journey of one plate. Have each student say the part that he/she represents as the "blood" moves through it. Ask where the oxygen comes from, and where it goes.

5. Start passing several plates through the system. As the plates go through the lungs, those students attach white foam discs to the plates. As the plates go through the capillaries, the body cells take off the white discs (oxygen) and attach blue discs (carbon dioxide) to the plates.

6. Explain that this is not a perfect model. In the human heart, for instance, the pulmonary artery branches off in two directions (one to each lung). Here we have only one artery leading to one capillary leading to one vein. In the human body, the arteries branch off ever smaller until they get to the network of capillaries.

Notes to the teacher: Oxygen Exchange

In addition to oxygen, blood also carries nutrients to the body cells. The villi, tiny finger-like parts lining the small intestine, absorb nutrients from digested food. Blood picks up the nutrients from the villi. Eventually, the body cells absorb the nutrients out of the blood. To get energy, the body's cells use oxygen to "burn" certain nutrients. This produces energy and a waste product: carbon dioxide. Along with oxygen and nutrients, blood carries hormones and antibodies to different parts of the body.

Blood consists of blood cells, platelets, and plasma. Red blood cells are responsible for carrying oxygen to the rest of the body. White blood cells help to fight infection. Platelets help your blood to clot when you get a cut. Plasma consists of water and many dissolved substances (such as proteins and salts) required by the body.

WebLinks

Lab #5 Blood

http://www.und.nodak.edu/dept/biology/introlab/bio100/blood.html
Go to this site to see a movie that depicts blood flow in the capillaries of a goldfish.

Blood Circulation Lab

http://unite.ukans.edu/explorer/explorer-db/html/783750574-4...
Here is a rough example of the Procedure used for a lab similar to the above.

| lesson 1: Pulse of Life| lesson 2: Keeps on Pumpin' | lesson 3: Under Pressure | lesson 4: Sounds of the Heart | lesson 4a: Valves and Pumps | lesson 5: Lub Dub (valves) | lesson 5a: The Heart as a Pump | lesson 6: Go With the Flow | lesson 7: Lung Model | lesson 8: Ins and Outs of Respiration | lesson 9: Catch Your Breath | lesson 10: O₂ CO₂ Skit | lesson 11: X-Rays |

Habits of the Heart ©2000 Science Museum of Minnesota