Overview
This lecture explains what happens to blood after it is drawn, focusing on blood centrifugation, composition, and key terms like plasma, serum, hematocrit, anemia, and polycythemia.
Blood Collection and Preparation
- Blood is drawn and collected into a special tube with chemicals to prevent clotting.
- Tubes are gently mixed to ensure the anti-clotting agent is effective.
- The blood sample is labeled and taken to a lab for analysis.
Centrifugation Process
- Centrifugation is the process of spinning blood samples at high speed to separate components by density.
- The centrifuge creates centrifugal force, causing dense components to move to the bottom of the tube.
Blood Components After Centrifugation
- Three layers appear: plasma (top, least dense, 55% of volume), white blood cells and platelets (middle, <1%), and red blood cells (bottom, most dense, 45%).
- Plasma is mostly water (90%), with proteins (8%) like albumin, antibodies, and fibrinogen, and 2% hormones, electrolytes, and nutrients.
- The thin middle layer contains white blood cells and platelets.
- The bottom layer consists of red blood cells carrying hemoglobin.
Plasma vs. Serum
- Plasma includes fibrinogen and clotting factors, while serum is plasma without these proteins.
Hematocrit and Related Terms
- Hematocrit is the percentage of blood volume made up by red blood cells.
- Normal hematocrit varies by age, gender, and factors like altitude.
- High hematocrit (polycythemia): high red blood cell volume.
- Low hematocrit (anemia): low red blood cell volume.
Key Terms & Definitions
- Centrifugation — spinning a sample to separate its components by density.
- Plasma — the liquid part of blood, mostly water, with proteins, hormones, electrolytes, and nutrients.
- Serum — plasma without clotting proteins (fibrinogen, clotting factors).
- Hematocrit — percentage of blood volume occupied by red blood cells.
- Polycythemia — abnormally high hematocrit (high red blood cell volume).
- Anemia — abnormally low hematocrit (low red blood cell volume).
- Albumin — plasma protein that maintains fluid balance in blood vessels.
- Antibodies — proteins in plasma involved in immune defense.
- Fibrinogen — plasma protein important for blood clotting.
Action Items / Next Steps
- Review and memorize the definitions of plasma, serum, hematocrit, anemia, and polycythemia.
- Understand the process and significance of blood centrifugation.
- Study the functions of major blood proteins (albumin, antibodies, fibrinogen).