What's in your blood? Question: What is inside blood? 1. Observe: Look at the Microscopic view of blood sample. Sketch what you see in the space at right. (If you like, you could also click the camera icon to take a Gizmo snapshot, and then paste your snapshot into a blank word-processing document.) Find and label the following objects in your sketch: . Red blood cells (small, round cells that carry oxygen) White blood cells (large, irregular cells that fight disease) Platelets (tiny fragments that help to stop bleeding when you are cut) 2. Collect data: Blood carries many vital substances. Four of these are listed above the Microscopic view. Oxygen and sugar are needed by all body cells. Carbon dioxide and urea are waste products. What are the concentrations of each substance in this sample? Oxygen: Carbon dioxide: Sugar: Urea: 3. Investigate: Take samples of blood from all over the body. Try to determine where sugar enters the blood, and where it is removed. A. Where does sugar enter the blood? B. How can you tell where sugar enters the blood? C. Where is sugar removed from the blood? D. How can you tell? 4. Investigate: Take blood samples to determine where urea enters the blood and is removed. A. Where does urea enter the blood? B. Where is urea removed from the blood?