unit 4: blood Flashcards
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
Antibodies
Y-shaped proteins secreted by white blood cells that attach to specific antigens to destroy them
antigen
Substance that provokes an immune response in the body
Antigen – antibody response
reaction in which antibodies attached a specific antigens; causes agglutination, in cross body-type transfusion
Area origin
The location of a blood source viewed in three dimensions as determined by projecting angles of impact of individual blood stains
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 blood stain
swipe
blood pattern resulting from a lateral transfer from a moving source onto another surface
Wipe
smeared blood pattern created when an object moves through blood that is not completely dried
who discovered proteins? when were they discovered?
discovered in 1900 by Karl Landsteiner
studying blood can identify….?
the presence or absence of particular proteins in the blood
true or false: identifying blood type is slower and more expensive than DNA profiling
false
What percentage of the the population has type A blood
42%
What percentage of the population has type B blood?
12%
What percentage of the population has type AB blood?
3%
What percentage of the population has type O blood?
43%
__% of the population has a ____factor on their blood cells
85; RH
Type A blood with RH factor is called __ while type A blood without RH factor is called __
Type A+; Type A-
Enzymes
complex proteins that catalyze different biochemical reactions
true or false: enzymes and proteins are important for elimination purposes
false; for identification purposes
knowing additional proteins and enzymes in the blood sample can….?
narrow the population group and increase the probability of identifying a suspect
red blood cells
help in oxygen and carbon dioxide exchange
platelets
help in blood clotting
white blood cells
fights against infections
1939
spatter patterns first analyzed
why does blood spatter?
a wound/injury is inflicted
patterns can help reconstruct the events surrounding a __, __, or __
shooting; stabbing; beating
analysis of spatter pattern can aid in determining the:
- direction blood traveled
- angle of impact
- point of origin of the blood
- velocity of the blood
- manner of death
Blood __ together
sticks
these droplets separate from the naim droplet
satellite pattern
these droplets form around the droplet
spike pattern
lines of convergence
two or more blood spatters can pinpoint the location of the blood source use trig
trail of circular drops of blood
person walking while bleeding
cast-off pattern
person repeatedly striking someone with a weapon while raising their arm
transfer pattern
person steps in blood or presses hand on a bloody surface and transfers the blood
wipe
trying to remove blood with a cloth or a finger
swipe
bloody hair or hand dragged across the floor
arterial gush
severed artery due to injury or attack
expired blood
injury causing internal bleeding; body trying to expel the blood
shadowing or void
object was in front of a surface but object was later removed
high velocity
- size is less than 1 mm
- lots of small blood drops in a cluster
- velocity is 100 ft/sec
- gunshots
medium velocity
- size of drops are 1-4 mm
- velocity of the blood is 25 ft/sec
- beating, stabbing
low velocity
- size of drops are more than 4 mm
- velocity is 5 ft/sec
- hammer or a blunt object
