White Blood Cell Identification and Techniques
White Blood Cell Identification
Videos and Resources
- Videos are available for download.
- Lab videos are in a new folder for the lab exam.
- Lecture notes page 12 discusses white blood cells.
Lab Setup
- Using microscopes with real human blood slides (blood smears).
- Slides are stained to show the nuclei of cells in purple.
- Slides vary in quality.
Capillary Exchange Review
- Capillaries are composed of simple squamous cells with molecular-sized pore gaps.
- Red blood cells and platelets are smaller than white blood cells.
- Red blood cells and large plasma proteins (e.g., albumin) are too big to fit through capillary pores.
White Blood Cell Movement
- Some white blood cells (neutrophils and monocytes) can move out of capillaries via the gaps.
- They can change their shape and move like an amoeba.
- This process is called diapedesis (or emigration).
- Diapedesis allows white blood cells to leave blood plasma and enter the interstitial fluid.
Purpose of Diapedesis
- White blood cells leave the blood at capillaries, especially in areas of inflammation or infection.
- Inflammatory chemicals attract white blood cells.
- Neutrophils and monocytes detect chemicals and move towards them.
- This movement is positive chemotaxis.
- Amoeboid movement: changing shape to move.
- Positive chemotaxis: detecting and moving towards chemicals.
- Phagocytosis: engulfing and eating bacteria or debris.
Inflammation and Capillary Permeability
- Inflammatory chemicals (leukotrienes, eicosanoids, prostaglandins) attract white blood cells and increase capillary permeability.
- Increased permeability allows white blood cells (especially neutrophils) to reach the infection site.
- Side effects: redness and swelling due to fluid leakage.
Identifying White Blood Cells in Lab
- Using photoshopped images to show all types of white blood cells in one view.
- In real slides, it is rare to see all types in one field of view.
Types of White Blood Cells
- Neutrophils, basophils, and eosinophils
- Lymphocytes and monocytes
- Pictures, not microscopes, will be used for identification.
- Need to identify cells and know their main functions as listed on lab page 8.
- MLTs need to be experts in blood cell identification.
- Machines count blood cells, but abnormal readings require manual inspection with a microscope.
Neutrophils
- Most abundant type of white blood cell.
- Comprise 50-75% of white blood cells in a normal blood sample.
- Function as a high-speed mobile army.
- Clear/translucent appearance (leukocyte).
- Move in and out of the blood via diapedesis.
- Accumulation of neutrophils and debris can form pus, with pus composed mostly of neutrophils that have engulfed bacteria and cell debris.
- Multi-lobed nucleus (sausage link).
- Lightly stained granules.
Basophils
Eosinophils
Size Comparison
- Neutrophils, basophils, and eosinophils are about two red blood cells across.
Lymphocytes
- Slightly bigger than a red blood cell.
- Large purple nucleus that fills most of the cell.
- Second most abundant white blood cell.
- Responsible for antibody production (important for exam 3).
Monocytes
- Largest white blood cell.
- Much bigger than three or four red blood cells.
- Big purple nucleus with a lot of cytoplasm.
- May contain lysosomes (little bubbles).
- Can leave the blood and become macrophages (big eaters).
Microscope Usage
- Start on low power, then move up to see purple dots (white blood cells) and pink dots (red blood cells).
- Use high power to focus on white blood cells.
Oil Immersion Technique
- After focusing on high power, move the white blood cell halfway out of view.
- Place one drop of immersion oil on the slide where the light is.
- Click the oil lens (100x, marked with a white stripe) into place.
- Use only the fine tuner to focus, small adjustments (1/8th turn) in each direction.
- Adjust the light up.
- Once focused, move the stage around.
Expected Observations
- Mostly neutrophils and lymphocytes will be seen.
- Basophils and eosinophils are rare.
- Monocytes can be seen if lucky.