Ch. 8 Notes (use the PPT on netschool to help you, write in your journal!)
History of Blood Study
(Use Figure 8-1 to generate a time line in your journal. This is the only set of notes for this section.
You will need to know the following: 2500BC, 1901, 1940, 1984)
Composition of Blood
Blood consists of 4 things (list from most abundant to lease abundant):
Component
Function
1.
2.
3.
4.
Blood Typing
Blood typing uses the ____________ blood cells. It was discovered by _________________ in
__________.
Blood type is considered___________ evidence. Why is this? (Hint: cut out and tape figure 8-5 here,
under each Type, write the percentage of each in the US population. This will help you answer the
why part)
Rh factor is discovered in ________ by ___________________. About ___% of people have it and ___%
do not.
Blood type is determined by something called the __________-___________ response. Each red blood
cell will have specific proteins on their cells called ______________. These can be A type or B type.
Those who have no antigens are Type __________. Those that have both antigens are Type ________.
Y-shaped proteins called _______________ recognize the antigens as “foreign” and destroy them if they
enter into the body.
-So if a person is Type A, they have A antigens. So they make antibodies against B antigens
(because those don’t belong in a Type A body). Draw an antibody. Label where the antigen
binds.
When an antibody collects enough antigens, the WBC will come and destroy them. This collection in one
place is called clotting or ______________________.
We use this to our advantage to determine blood types by adding artificial antibodies to an unknown
blood type and see if they clot. If they do, then the unknown blood as those antigens.
EX. An unknown blood source exhibits clotting when antibodies A are added, but not when
antibodies B are added. Therefore, the blood type is A (because Antibody A recognizes antigen A
and binds it, antibody B doesn’t recognize anything because antigen B isn’t there).
You try: An unknown blood source exhibits no clotting when antibodies A or antibodies B are
added. The blood type is therefore, type ________________. WHY?
Probability and Blood Type
This is math. If you want to find the probability of inheriting a specific blood type, you multiply the two
independent probabilities of each together.
Ex. The probability of getting AB- (A antigen, B antigen, no Rh is the -)
3% (AB) x 15% (no Rh)= .03 x .15= .0045 or .45% (pretty rare!)
You try: The probability of getting A+
The probability of getting OBlood Spatter Patterns
History:
1895- Piotrowski (earliest use of it)
1939- Balthazard (uses it in analysis of a crime)
1955- Sam Shepard is exonerated using it
1971- Physics is integrated to improve analysis in forensics
Blood falls a droplet and is domed shape. This is due to 2 things:
-________________: the molecules in blood stick to each other
-________________: blood molecules stick to other surface molecules
(Hint: these things are the same things in water)
If blood separates from the main drop, it’s called __________________. The __________ form when
blood hits a porous surface, but DO NOT separate from the main drop. (Cut out and paste figure 8-15
here, this will also help you answer the question. Also, cut out and paste figure 8-18, these are the
different types of spatter patterns)