Questions and Answers
What is serology?
The study of bodily fluids left at a crime scene.
What's the difference between a presumptive and confirmatory test?
Presumptive tests establish if a substance is present; confirmatory tests identify the substance.
Name the components of blood.
Plasma, erythrocytes, leukocytes, hemoglobin.
What are leukocytes and what do they do?
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What is a blood group?
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List three presumptive tests for blood.
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What's luminol?
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What does the precipitin test determine?
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What is the most common presumptive test for semen?
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How long can motile sperm survive in the vagina?
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Name the presumptive test for saliva.
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What's the difference between a wipe and a swipe?
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What is a cast-off stain?
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How is point-of-origin determined?
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Is there a presumptive test for urine?
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What is the angle of impact?
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What is the difference between forward and backward splatter?
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What is acid phosphatase?
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What are lymphocytes?
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What is blood?
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What is genome?
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What are platelets?
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Who discovered human blood groups?
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What is semen?
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What is saliva?
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What is urine?
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What is bloodstain pattern analysis?
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What are passive bloodstains?
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What are transfer bloodstains?
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What are projected/impact bloodstains?
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What is splatter?
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What are fly spots?
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What are skeletonized stains?
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What is point of origin?
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Study Notes
Serology and Blood Overview
- Serology studies bodily fluids collected at crime scenes, providing crucial evidence for investigations.
- Blood is a tissue comprising various cells suspended in plasma, about 90% water and 10% other substances.
Blood Testing Techniques
- Presumptive tests indicate the presence of a substance but lack specificity; examples include Leuchomalachite green, Bendizine, and Phenolphthalein.
- Confirmatory tests definitively identify substances, distinguishing them with accuracy.
- Common tests for blood include Luminol, which reacts with blood under black light to make it visible.
- The precipitin test differentiates between human and animal blood.
Components of Blood
- Erythrocytes (red blood cells) transport oxygen throughout the body.
- Leukocytes (white blood cells) are vital for immune defense against infections.
- Hemoglobin is the protein responsible for oxygen transport within erythrocytes.
- Platelets are cell fragments essential for blood clotting.
Blood Types and Groups
- Blood is classified into groups based on the presence of specific antigens; types include A, B, AB, and O, with O being the universal donor.
- Karl Landsteiner discovered human blood groups, enhancing transfusion safety.
Semen and Saliva Analysis
- Brentamine Fast Blue B is the most common presumptive test for semen presence.
- Saliva can serve as evidence in various crimes, although detection can be challenging; Phadebas tests for amylase in saliva.
Evoking Blood Patterns
- Bloodstain pattern analysis (BPA) reconstructs events at a crime scene through the study of bloodstain dispersion, shape, and number.
- Passive bloodstains are caused by gravity, including drops and pools.
- Transfer bloodstains result from contact between a blood-stained object and another surface, including wipes and swipes.
- Projected bloodstains occur due to force, producing splatters or spurts.
Bloodstain Characteristics
- Cast-off stains result from blood flinging off a moving object.
- The angle of impact refers to the angle at which blood strikes a surface, influencing stain shape.
- Forward splatter occurs when blood is projected away from the impact site, while backward splatter returns toward it, often being smaller in size.
- Skeletonized stains indicate the aging of a stain, preserving its original shape and size.
Unique Biological Entities
- Lymphocytes are white blood cells generated in the bone marrow and thymus, playing a significant role in immune response.
- Acid phosphatase is an enzyme present in semen, helpful in forensic analysis.
- The genome consists of the complete genetic material of an individual.
Urine Testing
- Urine can be presumptively tested for urea or creatine, indicative of its presence as waste filtered by the kidneys.
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Description
Test your knowledge on serology and blood components with these flashcards. Learn the definitions, differences between test types, and key components of blood. Perfect for students or anyone interested in forensic science.