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Published byFrederick Casey Modified over 8 years ago
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Forensic Science
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Blood What is made of? SUBSTANCE HOW DO WE KNOW IT’S BLOOD? Human?? Animal?? What does it do when it “travels”? BLOOD SPATTER
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What makes up our blood? RED BLOOD CELLS (Erythrocytes) – –MOST ABUNDANT…contain HEMOGLOBIN –Do NOT have a nucleus – so they don’t have _______?? WHITE BLOOD CELLS (Leukocytes) – –IMMUNE CELLS PLASMA – –YELLOWISH LIQUID - nutrients and vitamins, hormones, clotting factors, and antibodies. PLATELETS (Thrombocytes) – –coagulate (clot) your blood, when you have a wound
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What are blood types? UNIVERSAL DONORS: O type Rh – UNIVERSAL RECIPIENTS: AB type Rh +
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How common is your blood type? 46.1% 38.8% 11.1% 3.9%
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How do we know it’s blood? And if it’s blood, is it HUMAN? Is it blood? Kastle-Meyer test Uses Phenolthalein Detects Hemoglobin Turns pink if +
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KASTLE-MEYER video clip
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How do we know it’s blood? Is it blood (big area)? Luminol Drawbacks !! Some metals, paints, cleaning products, and plant materials also react. Can destroy DNA in blood.
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Luminol can destroy evidence (DNA) http://www.youtube.com/watch?v=iNl-I4DUSyI
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Crime Scene Analysis: Luminol in action
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And if it’s blood, is it HUMAN? Is it HUMAN blood? Precipitin test 1. Inject rabbits w/ human blood 2. They will make ANTIBODIES to it 3. Extract antibodies from rabbit 4. Combine antibodies w/ crime sample 5. A precipitate line appears in tube if +
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And if it’s blood, is it HUMAN? PRECIPITIN TEST Draw a test tube
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And if it’s blood, is it HUMAN? PRECIPITIN TEST Draw a test tube. Like this one…
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Is it HUMAN?? Microscope Views (visual examination) Bird Blood Cat Blood Dog Blood Fish Blood Frog Blood Snake Blood Human Blood Horse Blood
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