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Blood and Blood Spatter. Blood. 3 Types of Cells Red Blood Cells White Blood Cells Platelets All contained in plasma that contains proteins: Antibodies Hormones Clotting factors Nutrients (amino acids, minerals, etc.). Blood Cells. Red Blood Cells
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Blood • 3 Types of Cells • Red Blood Cells • White Blood Cells • Platelets • All contained in plasma that contains proteins: • Antibodies • Hormones • Clotting factors • Nutrients (amino acids, minerals, etc.)
Blood Cells • Red Blood Cells • Hemoglobin in the cell is iron-containing protein that transport oxygen to the tissues of the body • White Blood Cells • Fights diseases and foreign invaders • Platelets • Aid in blood clotting and are involved in repairing damaged blood vessels
Antibodies • B-lymphocytes (special white blood cells) secrete antibodies • Helps white blood cells identify foreign proteins • Y-shaped proten molecule that binds to the shape of an antigen. • The binding site of the antibody is located on the tip of the Y and the antibody recognizes a foreign substance as an invader and attaches to it.
DNA PROFILING • Dr. Alec Jeffreys used white blood cells as a source of DNA to produce the first DNA Profile • DNA profiling or DNA fingerprinting is widely accepted in programs such as The Innocence Project to help free inmates who have been falsely convicted of crimes.
Blood Splatters • Passive Fall • Blood falls directly to floor at 90-degree angle produces circular drops • Arterial spurts • Typically found on walls or ceilings causes by the pumping action of the heart • Splashes • Shaped like exclamation points • Can help locate the position of the victim at time of attack
Blood Splatters • Smears • Left by bleeding victims depositing blood as they touch something • Trails • Left my bleeding victims trying to move • Droplets can appear as round, smeared, or spurts • Pools • Form around victim who is bleeding heavily
Directionality of Blood • The shape of an individual blood drop provides clues to the direction of where the blood originated. • Circular drop: blood fell straight down • Elongated: possible to determine direction the blood was traveling as it struck the surface • Blood strikes the surface • Cohesion: force between 2 similar substances • Adhesion: force between 2 unlike surfaces (ex- blood and wall) • Surface tension: elastic characteristic along the outer edge of liquid caused by attraction of like molecules