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Chapter 10 Blood “Out damned spot! Out, I say
07/18/08 Chapter 10 Blood “Out damned spot! Out, I say Here’s the smell of the blood still, All the perfumes of Arabia will not Sweeten this little hand. Oh, Oh, Oh!” —William Shakespeare’s Lady Macbeth, in Macbeth
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Serology Serology is the examination and analysis of body fluids.
07/18/08 Serology Serology is the examination and analysis of body fluids. A forensic serologist may analyze a variety of body fluids including saliva, semen, urine, and blood. 1950 to the late 1980’s - most important part of lab procedures. With the development of DNA techniques - more time, money, and significance was placed in developing DNA labs. Limited funds and the time required for DNA testing, most labs still use many of the basic serology testing procedures. Kendall/Hunt Publishing Company
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Blood Facts The average adult has about FIVE liters of blood inside of their body, which makes up 7-8% of their body weight. Blood is living tissue that carries oxygen and nutrients to all parts of the body, and carries carbon dioxide and other waste products back to the lungs, kidneys and liver for disposal. It also fights against infection and helps heal wounds, so we can stay healthy. There are about one billion red blood cells in two to three drops of blood. For every 600 red blood cells, there are about 40 platelets and one white cell.
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Kendall/Hunt Publishing Company
07/18/08 Blood Components Plasma: fluid (55%) Cells (45%) Erythrocytes – RBC; responsible for O2 distribution. Leukocytes - WBC; responsible for “cleaning” the body of anything foreign. Thrombocytes or platelets; responsible for blood clotting Serum: liquid that separates from the blood when a clot is formed. Kendall/Hunt Publishing Company
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What makes up our blood? RED BLOOD CELLS (Erythrocytes) – The most abundant cells in our blood; they are produced in the bone marrow and contain a protein called hemoglobin that carries oxygen to our cells. WHITE BLOOD CELLS (Leukocytes) – They are part of the immune system and destroy infectious agents called pathogens. PLASMA – This is the yellowish liquid portion of blood that contains electrolytes, nutrients and vitamins, hormones, clotting factors, and proteins such as antibodies to fight infection. PLATELETS (Thrombocytes) – The clotting factors that are carried in the plasma; they clot together in a process called coagulation to seal a wound and prevent a loss of blood.
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Genetics of Blood Types
Your blood type is established before you are BORN, by specific GENES inherited from your parents. You inherit one gene from your MOTHER and one from your FATHER. These genes determine your blood type by causing proteins called AGGLUTINOGENS to exist on the surface of all of your red blood cells.
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Kendall/Hunt Publishing Company
07/18/08 Human Blood Red blood cells are most numerous; 5 to 6 million per mm3 White blood cells are larger and less numerous; 5 to 10,000 per mm3 Platelets are tiny, cellular fragments; 350 to 500,00 per mm3 Kendall/Hunt Publishing Company
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Historical Perspective of Blood Typing
07/18/08 Historical Perspective of Blood Typing Karl Landsteiner discovered that there are four different types of human blood Landsteiner and Weiner reported the discovery of the Rh factor 85% of Caucasians, 94% of Black Americans and 99% of all Asians are Rh positive. Kendall/Hunt Publishing Company
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07/18/08 Blood Terminology ABO blood groups—based on having an A, B, both or no antigens on red blood cells Rh factor—may be present on red blood cells; positive if present and negative if not Antigen—a substance that can stimulate the body to make antibodies. Certain antigens (proteins) found in the plasma of the red blood cell’s membrane account for blood type. Antibody—a substance that reacts with an antigen Agglutination—clumping of red blood cells; will result if blood types with different antigens are mixed Kendall/Hunt Publishing Company
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AA or AO = Type A BB or BO = Type B OO = Type O AB = Type AB
What are blood types? There are 3 alleles or genes for blood type: A, B, & O. Since we have 2 genes, there are 6 possible combinations. Blood Types AA or AO = Type A BB or BO = Type B OO = Type O AB = Type AB
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How common is your blood type?
46.1% 38.8% 11.1% 3.9%
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Blood Transfusions O A B AB Universal Donor Rh + Can receive + or -
A blood transfusion is a procedure in which blood is given to a patient through an intravenous (IV) line in one of the blood vessels. Blood transfusions are done to replace blood lost during surgery or a serious injury. A transfusion also may be done if a person’s body can't make blood properly because of an illness. Who can give you blood? People with TYPE O blood are called Universal Donors, because they can give blood to any blood type. People with TYPE AB blood are called Universal Recipients, because they can receive any blood type. Rh + Can receive + or - Rh - Can only receive - Universal Donor A B O AB Universal Recipient
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Blood Groups Type Antigen Antibody A A B A, AB O, A B, AB O , B B B A
07/18/08 Blood Groups Can Give Blood To Can Get Blood From Type Antigen Antibody A A B A, AB O, A B, AB O , B B B A Neither A nor B AB A and B AB A, B, O, AB Neither A nor B O A and B A, B, O, AB O Kendall/Hunt Publishing Company
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Unknown Stain at a Scene
07/18/08 Unknown Stain at a Scene Questions to be answered: Is it blood? Is it human blood? Whose is it? Determine blood type, alcohol content, drugs present Determine the method(s) in which blood may have been deposited Determine Kendall/Hunt Publishing Company
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Presumptive Tests for Blood Determination
07/18/08 Presumptive Tests for Blood Determination Kastle-Meyer color test – a mixture of phenolphthalein and hydrogen peroxide; the hemoglobin will cause the formation of a deep pink color if blood is present Hematest® tablet - reacts with the heme group in blood causing a blue-green color Luminol test – reaction with blood to produce light reaction Kendall/Hunt Publishing Company
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Human vs Animal Blood Microscopic observation Precipitin test—
07/18/08 Human vs Animal Blood Microscopic observation Precipitin test— Use a human antiserum, place blood in the presence of the antiserum, the sample will react with human proteins if human blood is present. Kendall/Hunt Publishing Company
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Kendall/Hunt Publishing Company
07/18/08 Animal Blood Larger nucleic red blood cells Frog Blood Human Blood Kendall/Hunt Publishing Company
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Blood Evidence Blood type? If you can determine the DNA?
07/18/08 Blood Evidence Blood type? Class If you can determine the DNA? Individual Blood stain patterns are considered circumstantial evidence in a court room. Experts could argue many points: Direction of travel, height of the perpetrator, position of the victim, left/right hand, whether the body was moved, etc. Kendall/Hunt Publishing Company
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Blood Evidence Blood samples – Can be analyzed to determine blood type and DNA, which can be matched to possible suspects. Blood droplets – Can be analyzed to give clues to the location of a crime, movement of a victim, and type of weapon. Blood spatter – Can be analyzed to determine patterns that give investigators clues to how a crime might have happened.
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07/18/08 Secretors Blood-type antigens are found in high concentration in their body fluids… Saliva Semen Vaginal secretions Gastric juice. 80% of the population Kendall/Hunt Publishing Company
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