Download - Chapter 11; Blood
![Page 1: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/1.jpg)
Chapter 11; Blood
![Page 2: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/2.jpg)
Serology; the study of bodily fluids
![Page 3: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/3.jpg)
Separation of blood
• Living portion of blood is:• Erythrocytes (red blood cells…
RBCs)• Leukocytes (white blood cells)• Platelets
Liquid part of the blood with no cells in it is called the plasma.(Mostly water with salts, ions, proteins.)
![Page 4: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/4.jpg)
![Page 5: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/5.jpg)
BLOOD TRANSFUSIONS were not working!
OUTLAWED IN MOST COUNTRIES IN EARLY 1900’S
![Page 6: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/6.jpg)
ABO Blood Typing (Karl Landsteiner – 1901)A classification of blood: A, B, AB, O
Rhesus monkey factor (Rh) discovered in 1940.If you have it, you’re Rh+ and if you don’t you’re Rh-
![Page 7: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/7.jpg)
Theoretically, no two people have the same combination of blood factors and it should be possible to individualize evidence using blood, but in reality this is not the case.
Testing for every factor on RBCs in not practical, and many factors break down as blood dries and ages.
Blood is still important in forensics because testing can be done on both whole blood and dried bloodstains quickly and inexpensively.
![Page 8: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/8.jpg)
ANTIGENS AND ANTIBODIES
![Page 9: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/9.jpg)
Each antibody binds to a specific antigen; an
interaction similar to a lock and key.
The antibody destroysthe antigen
![Page 10: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/10.jpg)
![Page 11: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/11.jpg)
AGGLUTINATIONTHE CLUMPING
TOGETHEROF RED BLOOD
CELLS
![Page 12: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/12.jpg)
Lattes slide method
Uses antibody-antigen
reactionsto test for
blood types
![Page 13: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/13.jpg)
Varies by country, ethnic group, etc.
![Page 14: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/14.jpg)
![Page 15: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/15.jpg)
Blood typing can be used to:
-show that two samples had different origins (exclude a suspect)
-determine the probability of an individual having a particular blood type
![Page 16: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/16.jpg)
What is the probability that an American has type AB- blood?
4/100 x 15/100 = 60/10,000 or 0.6%
![Page 17: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/17.jpg)
Blood Tests
Determines whether a substance is blood or not, but does NOT distinguish between human and animal blood. Hemastix test
![Page 19: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/19.jpg)
PRECIPITIN TEST• Determines if
blood is human
• An animal (mammal) is injected with sample. If human, animals produce antibodies.
![Page 20: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/20.jpg)
Non-mammals
Oval red blood cells with a visible nucleus
![Page 21: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/21.jpg)
Mammals
• Circular red-blood cells
• No nucleus
![Page 22: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/22.jpg)
Secretors• 80 % of population• Blood type antigens
are secreted in bodily fluids (saliva, semen,
perspiration,gastric and vaginal secretions)
![Page 23: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/23.jpg)
Blood enzymes
Proteins that regulate chemical reactions
![Page 24: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/24.jpg)
Iso-enzymesProtein components into which enzymes can be separated
(1) PGM – an enzyme that has 10 variations
(2) importance- allows forensic scientists to reduce the number of possible sources
![Page 25: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/25.jpg)
BLOOD SPATTER
![Page 26: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/26.jpg)
SIZE AND SHAPE OF DROPSARE AFFECTED BY:
• HEIGHT OF FALL
• ANGLE OF IMPACT
• SURFACE ON WHICH THE DROPS LAND
![Page 27: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/27.jpg)
Shape is determined by the impact angle
![Page 28: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/28.jpg)
Determination of Impact Angle
Measure the length and widthof the stain
![Page 29: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/29.jpg)
• Divide the width by the length to get arc sine of the impact angle
Width / Length = arc sine of impact angle
Ex: width = 2.4 cm length = 3.1 cm
Ratio of width/length =2.4 cm / 3.1 cm =
.77419
![Page 30: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/30.jpg)
Use your calculator to get the impact angle
Enter:
“sin -1 (.77419)”
Answer:
50.7 degrees
50.7
![Page 31: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/31.jpg)
Blood spatter labs
1. Height of drops vs. drop size
2. Angle of drop vs. drop shape
3. Surface texture vs. drop size and shape
![Page 32: Chapter 11; Blood](https://reader035.vdocuments.us/reader035/viewer/2022062521/568166df550346895ddb1129/html5/thumbnails/32.jpg)
The Nobel Prize in Physiology or Medicine – Educational
(Blood type simulation)