CHAPTER 8.1: BLOOD AND BLOOD SPATTER * Change Your Life

* C HAPTER 8 B LOOD AND B LOOD S PLATTER B Y THE END OF THIS CHAPTER YOU WILL BE ABLE TO : o Explain the composition of blood o Describe the function of blood cells o Discuss the cellular components of blood. o Elucidate the importance of the white blood cell. Change Your Life

V OCABULARY o Agglutination o Antibodies o Antigen-antibody response o Antigen o Cell-surface protiens o Red blood cells o White blood Cells * Change Your Life

* I NTRODUCTION AND H ISTORY o Blood typing provides class evidence o DNA profiling provides individual evidence o A blood splatter pattern provides information ● the truthfulness of an account by a witness or a suspect ● the origin of the blood ● the angle and velocity of impact ● the type of weapon used Change Your Life

W HAT IS THE DIFFERENCE BETWEEN C LASS AND INDIVIDUAL E VIDENCE ? o Class evidence: material that connects an individual or thing to a certain group. o Individual evidence: a kind of evidence that identifies a particular person or thing. * Change Your Life

WHAT IS BLOOD? o Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells. o Blood consists of cellular components and plasma containing dissolved ions, proteins, and other molecules. o The adult human body contains 5.5 liters (6 quarts) of blood. o The heart pumps nearly 300 liters every minute. * Change Your Life

* C OMPOSITION OF B LOOD o Plasma—a liquid suspending other blood components o Red blood cells (Erthrocytes)— carries oxygen to the body’s cells and carbon dioxide away o White blood cells (Leukocytes)— fights disease and foreign invaders and, alone, contain cell nuclei o Platelets—aids in blood clotting and the repair of damaged blood vessels Change Your Life

* C OMPOSITION OF B LOOD White blood cells are the only type of blood cell that contains a nucleus. They are the only blood cell that can be used as a source of DNA for DNA profiling (fingerprinting). Change Your Life

W HERE D OES B LOOD C OME F ROM ? * Change Your Life

* C ELLULAR C OMPONENTS OF B LOOD Change Your Life

* B LOOD T YPING —P ROTEINS o Discovered in 1900 by Karl Landsteiner o He Identified the presence or absence of particular proteins (A or B) embedded in the red blood cell o Quicker and less expensive than DNA profiling o Produces class evidence but can still link a suspect to a crime scene or exclude a suspect Change Your Life

* B LOOD T YPING —P ROTEINS 42%12%3%43% of the population in the United States The presence or absence of these cell-surface proteins give rise to our present system of blood typing. An antibody reaction test is used to identify each blood type. Change Your Life

* R H F ACTOR 85% of the population has a protein called RH factor on their blood cells Change Your Life

N AMING OF B LOOD T YPES o A person’s blood type is based on the presence of absence of AB and Rh proteins. o The presence of different blood types was not discovered until o When a person receives a blood protein that is foreign to him or her, antibodies (antigen- antibody response) will cause the blood to clump (agglutination) and may cause death. * Change Your Life

* B LOOD T YPING —A NTIBODIES o Antibodies are Y-shaped proteins secreted by white blood cells that attach to antigens to destroy them o Antigens are foreign molecules or cells that react to antibodies Change Your Life

* B LOOD E NZYMES o Many other blood proteins have been identified. o The presence or absence of these proteins is inherited from our parents. o In addition to A, B, and Rh protein, people can have M proteins and N proteins. o Many enzymes and proteins have been found in the blood that are important for identification purposes. o Enzymes are complex proteins that catalyze different biochemical reactions Change Your Life

* B LOOD T YPING —P ROBABILITY AND B LOOD T YPES o The probability of a blood type equals the product of probabilities for each protein group If Type A = 42% and Rh Factor = 85% Then A+ =.42 x.85 =.357 (35.7%) o Knowing additional proteins and enzymes in the blood sample ● Narrows the population group ● Increases the probability of identifying a suspect Change Your Life

* S UMMARY o Blood consists of cellular components and plasma. o The various human blood types are caused by the presence or absence of A and/or B proteins on the surface of red blood cells. Change Your Life

HOMEWORK #17 o What is the function of blood and where is it produced? o Name three types of blood cells and give their functions. o Which type of blood cell is used for DNA profiling? Why? o List 5 types of White Blood Cells. o Describe how cell-surface proteins relate to how we categorize our present system of blood typing. o What is agglutination? o What percentage of the U.S. population have Type AB blood? o What is your blood type? * Change Your Life