AP Lab: Blood – Red Blood Cells

Lab Exercises

Exercise 1: Identifying Red Blood Cells on a Microscope Slide

  • Objective: Observe a blood sample on a microscope slide and identify the following formed elements:
    A. Erythrocyte (red blood cells)
    B. Leukocyte (white blood cells)
    C. Thrombocyte (platelets)
  • Predominant Cell Type:
    • The predominant cell in this sample is ________________________________
  • Size Comparison:
    • Are red blood cells or white blood cells larger? ________________________________________

Exercise 2: Measuring Hematocrit

  • Definition: Hematocrit is the percent of the blood volume made up of formed elements, primarily comprising red blood cells.
  • Measurement Method:
    • The hematocrit level is measured through centrifugation, which causes blood components to settle into layers.
  • Procedure to Measure Hematocrit: A. Fill a capillary tube ¾ full with the blood sample following the instructor's instructions. B. Seal one end of the tube by pressing it into Crit-O-Seal clay with your finger over the opposite end. C. Place the tube in the centrifuge with the sealed end facing outward. D. Have the instructor spin the centrifuge for 3-5 minutes. E. Remove the capillary tube and observe the different layers created. F. Use the Hematocrit Readers to determine the percentage of hematocrit present, following the written instructions on the Readers. G. Alternatively, measure the total blood sample height (in centimeters) and the height of just the red blood cell layer.
    • Calculate hematocrit percentage:
      ext{Hematocrit ( ext{ extperthousand})} = rac{ ext{height of red blood cell layer}}{ ext{total blood height}} imes 100

Label the Layers of Centrifuged Blood

  • Layers:
    A. Red blood cells
    B. Buffy Coat
    C. Plasma
  • Hematocrit Level:
    • What is the hematocrit level/percentage of your sample? ________________________________
  • Composition of Buffy Coat:
    • What makes up the “Buffy Coat” layer? ________________________________________________

Exercise 3: Measuring Hemoglobin

  • Function of Hemoglobin: Hemoglobin constitutes a large part of red blood cells and is responsible for transporting oxygen and carbon dioxide in the blood.
  • Measurement Method:
    • A Hemoglobinometer will be used to automatically read the hemoglobin level of a controlled blood sample.
  • Procedure for Measuring Hemoglobin:
    C. Place a drop of blood on a piece of parafilm.
    D. Fill the cuvette with blood by angling it downward against the drop.
    E. Insert the filled cuvette into the hemoglobinometer, which will automatically provide a reading of the hemoglobin amount.
  • Hemoglobin Reading:
    • What was your reading from the hemoglobinometer? _______________________________
  • Oxygen and Carbon Dioxide Transport:
    • Which portion of hemoglobin binds to and transports oxygen? ____________________________
    • Which portion of hemoglobin binds to and transports carbon dioxide? ______________________

Exercise 4: Red Blood Cell Count

  • Definition of Hemocytometer: The appearance and count of red blood cells can be determined using a hemocytometer, which is a specialized slide marked with a grid for accurate cell counting from a diluted blood sample.
  • Formula for Calculating Red Blood Cell Counts:
    • What is the formula for calculating red blood cell counts using a hemocytometer? _______________

Post-Lab Questions

  1. Anemia:
    • Definition: What is anemia?
    • Effects: Why might someone with anemia have low energy levels?
  2. Polycythemia:
    • Definition: What is polycythemia?
    • Implications: How and why would this affect an individual’s blood pressure?
  3. Shape of Red Blood Cells:
    • Importance: Why is it important that red blood cells are biconcave in shape?
  4. Blood Doping:
    • Influence: How does blood doping give an athlete an “unfair” advantage?
    • Dangers: Why is blood doping so dangerous?
  5. Gender and Hematocrit Levels:
    • Impact: How does gender affect an individual’s hematocrit level?