Forensic File #2 • A murderer thinks that they can wash away all signs of blood by using everyday household cleaners and then painting over the spots with new paint. • Will this work? Explain your answer.
Parts of Blood and Blood typing • Turn in your Intro to Serology Quiz • Today’s assignments: 1. Parts of Blood webquest/typing practice- on computer cart 2. Finish Animal blood comparison microscope lab- tables 2 or 3 3. Blood type probability problems- on front table • Animal blood lab, parts of blood webquest and probabability problems all due today
What are some characteristics of blood? • Plasma--fluid portion of the blood (55%) • Serum--liquid that separates from the blood when a clot is formed
Characteristics of blood • Cells (45%) • Erythrocytes--red blood cells; responsible for oxygen distribution • Leukocytes--white blood cells; responsible for “cleaning” the system of foreign invaders • Thrombocytes--platelets; responsible for blood clotting
What is the difference in blood types? • ABO blood groups--based on having an A, B, both or none of the factors on the red blood cell • Rh factor--may be present on the red blood cell; positive if present and negative if not
Blood typing facts • Around 1900, Karl Landsteiner discovered the 4 different types of human blood based on the presence/absence of antigens found on red blood cells • In 1940 Landsteiner and Weiner discovered the Rh factor. 85% of Caucasians, 94% or Black Americans, and 99% of all Asians are Rh positive
Back to blood typing • Antigen--a substance found on a red blood cell • Antibody--a substance that reacts with an antigen • Agglutination--clumping of red blood cells; will result if blood types with different antigens are mixed