Chapter 8 Test Flashcards
How long has blood been studied?
Blood has been studied since 2500 BC (4525 years), but its use of blood spatter analysis started in 1895
Who is Sir William Harvey?
Noted continuous circulation within the body
Who is Sir William Osler?
Discovered platelets
What determines a person’s blood type?
The presence or lack thereof of the antigens A and B and the Rh factor
Blood circulates two types of cells, what are they?
Red blood cells and white blood cells
What are red blood cells?
Blood cells carry respiratory gases, mainly oxygen, and carbon dioxide. The hemoglobin in red blood cells binds to oxygen in the lungs and transports it to cells in all the tissues.
What are white blood cells?
White blood cells fight disease and foreign elements in the body by provoking the immune system with antigen-antibody responses
What is the function of the immune system?
To protect our bodies by identifying cells or molecules that are foreign such as viruses, bacteria, fungi, and parasites.
What is plasma?
A liquid where red blood cells, white blood cells, and platelets are suspended throughout the body. Plasma carries antibodies, hormones, clotting factors, and nutrients like glucose, amino acids, salts, and minerals throughout the body.
What type of evidence is blood typing?
Class evidence
Know who Karl Landsteiner is
Discovered three blood types; A, B, O
How do you determine blood type?
You determine blood type by performing blood typing tests (antibodies of each antigen on red blood cells are mixed with blood to see if stick)
Different types of blood, A, B, AB, O
A- only has the A antigen
B- only has the B antigen
AB- has both the A and B antigen
O- has neither the A or B antigen
Who is Alexander Weiner?
He worked with Rhesus monkeys and discovered the Rh factor on red blood cells.
What is the largest percentage population’s blood type thing?
O, 43%
What is the term used for the clumping of red blood cells?
Agglutination
What happens to the blood when dropped from different distances?
When blood is dropped from different distances the size of the spatter changes. The higher up the blood is dropped from the bigger the spatter size will be due to more force and greater velocity. This is true until the blood reaches the height of terminal velocity then it will remain relatively the same size even if dropped from higher up
Know wipe and swipe blood stains
Wipe- Smeared blood pattern created when an object moves through blood that is not completely dried
Swipe- Blood pattern resulting from a lateral transfer from a moving source onto another surface
The attraction between molecules of unlike substances is called what?
adhesion
You can tell the type of blood spatter based on the size, 1-4 mm indicates what?
Less than 1 mm indicates gunshot wound
1-4mm indicates beating/stabbing
More than 4 mm indicates blunt object impact or dripping
Agglutination-
Clumping of cells caused by an antigen-antibody response
Angle of impact-
Angle at which blood strikes a target surface relative to the horizontal plane of the target surface
Antibodies-
Proteins secreted by white blood cells that attach to specific antigens
Antigen-
Substance that provokes an immune response in the body
Antigen-antibody response-
Reaction in which antibodies attach to specific antigens; causes agglutination in cross-blood-type transfusions
Area of convergence-
Two-dimensional view of the intersection of lines formed by drawing a line through the main axis of at least two drops of blood that indicates the general area of the source of the blood spatter
Area of origin-
The location of a blood source viewed in three dimensions as determined by projecting angles of impact of individual bloodstains
Cast-off pattern-
Blood projected onto a surface as a result of being flung from an object in motion
Passive drop-
Blood drop created solely as a result of gravity
Satellite-
Smaller droplets of blood projected from larger drops of blood upon impact with a surface
Spine-
Elongated blood streaks radiating away from the center of a bloodstain
