Blood Components
Plasma, Red blood cells, White blood cells, and Platelets
What do antigens determine?
Blood type!
What is agglutination?
Blood clotting from antibodies binding to opposing antigens
What are transfer bloodstains?
Bloodstains from when objects come in contact with blood and form impressions
What is a cast-off stain? (type of bloodstain and what it is)
A projected stain flung from a bloodied object or bleeding person
What are the four blood types?
A, B, AB, and O
What blood type is the universal donor? Why?
O-, it doesn't have A, B, or Rh antigens so antibodies won't trigger a immune response
Type O- clots with...
None!
What is the difference between the causes of passive and projected bloodstains?
Passive is caused by gravity alone
Projected is caused by a force that propells blood through the air
What types of bloodstains were present in the Darlie Routier case?
Passive, transfer, and projected
Trick! Class AND Exclusive
What blood type is the universal receiver? Why?
AB+, it has A, B, and Rh antigens and lacks A and B antibodies to trigger agglutination
Type B+ clots with...
Anti-B and Anti-Rh
A smooth surface causes a ______ bloodstain and a rough surface causes a ______ bloodstain.
Circular; irregular
What are examples of passive bloodstains?
Drip, pool, trail
List the blood types from rarest to most common
O, A, B, AB
What is a general rule for knowing which antibodies go along with which blood type? (What belongs to what?)
Antibodies are AGAINST your antigens (opposites!)
Type AB- clots with...
Anti-Rh
If a blood drop is 2cm in diameter and another is 5cm in diameter, which bloodstain was dropped from a greater height?
The blood drop that's 5cm in diameter
What are examples of transfer bloodstains?
Bloody prints, swipes, smears
What is the difference between antigens and antibodies?
Antigens are markers on the surface of red blood cells
Antibodies are proteins that fight foreign antigens
What kind of antibodies does AB produce?
None! (unless it's positive!)
What is the difference between a Rh+ recipient and Rh- recipient? (what blood types can they receive in a donation?)
Rh+ can receive both Rh+ and Rh-
Rh- can receive only Rh-
What direction did this bloodstain come from? (picture)
Right
Where was the projected stain in the Darlie Routier Case?
Back right shoulder of Darlie's shirt