froensics blood/ serology
Hemoglobin: Hemoglobin is the iron-containing protein in red blood cells that carries oxygen throughout the body and gives blood its red color.
Agglutination: Agglutination is the clumping of red blood cells that occurs when incompatible blood types are mixed.
Blood spatter: Blood spatter is the pattern that results when blood droplets are projected or dispersed through the air, which can reveal information about the events at a crime scene.
Luminol: Luminol is a chemical used in forensic testing that reacts with the iron in blood to produce a blue glow in the dark, even if the blood has been cleaned or is invisible.
Directionality: Directionality is the path that a blood droplet travels through the air, which can be determined by the shape of the stain.
Antibodies: Antibodies are proteins in the blood plasma that identify and attack foreign substances, such as incompatible blood antigens.
Plasma: Plasma is the liquid portion of blood that carries cells, nutrients, hormones, and waste products throughout the body.
Serum: Serum is the clear fluid that remains after blood has clotted; it contains antibodies but no clotting factors.
Antigens: Antigens are proteins on the surface of red blood cells that determine blood type (A, B, AB, or O).
Impact pattern: An impact pattern is a bloodstain pattern created when a force is applied to a source of liquid blood.
Swipe pattern: A swipe pattern is created when a bloody object moves across a clean surface, leaving a smear of blood in the direction of motion.
Void: A void is an empty area within a blood spatter pattern that indicates an object or person blocked the blood from hitting that surface.
Wipe pattern: A wipe pattern is created when an object moves through an existing wet bloodstain, altering its appearance.
Secretor: A secretor is a person whose blood-type antigens are also found in other body fluids such as saliva, semen, or sweat.
Part B
1. What three questions should be answered when examining an apparent dried bloodstain?
When examining an apparent dried bloodstain, a forensic scientist should ask: (1) Is it blood? (2) Is it human blood? (3) If it is human, whose blood is it?
2. Define a presumptive test.
A presumptive test is a preliminary test that indicates the possible presence of blood but does not confirm it without further testing.
3. How would a sample be identified by a forensic veterinarian as animal blood?
A forensic veterinarian can identify animal blood by using a precipitin test, which determines whether the blood contains animal proteins rather than human proteins.
4. What is a secretor?
A secretor is an individual who secretes their blood-type antigens into other body fluids, allowing their blood type to be determined from samples such as saliva or semen.
5. Define serology. How is it used in forensics?
Serology is the scientific study of blood and other body fluids. In forensics, it is used to identify bodily fluids at crime scenes and determine their possible source.
6. What happens if a person with type A blood is given type B blood? Explain.
If a person with type A blood receives type B blood, their immune system will recognize the B antigens as foreign and produce antibodies against them, causing the blood to clump (agglutinate) and possibly leading to serious complications or death.
7. To whom can a person with type AB blood donate to and from whom can they receive?
A person with type AB blood can donate only to individuals with type AB blood but can receive blood from all blood types (A, B, AB, and O) because they have no antibodies against A or B antigens.
9. Indicate the weapon used from the transfer pattern left at the scene.
The weapon can be identified by the shape and size of the blood transfer pattern like the rectangular shape might show a blunt object like a hammer, but a long, thin pattern could indicate it was a knife or pipe.