Intro to Blood and Blood Types

Important Vocab: Fill in vocab table from notes for homework! Antigen Plasma Red blood cells White blood cells Antibodies Agglutination

Unknown Stain at a Scene Questions to be answered: Is it blood? Is it human blood? Whose is it? Determine blood type, alcohol content, drugs present Determine the method(s) in which blood may have been deposited We’re going to do this first :) 3

Blood Facts! Average adult has about 5 liters of blood Carries oxygen, nutrients, carbon dioxide and other wastes Fights infections Made up of 4 things: Red blood cells (RBCs) White blood cells (WBCs) Platelets Plasma

Composition of Blood 5

What can each part tell us? Plasma Liquid part of blood Carries nutrients, waste products, hormones, and many other things. What do you think forensic scientists can determine from studying the plasma? 6

What can each part tell us? 2. White blood cells Fight off diseases and foreign substances. Only blood cells with a nucleus. What do you think forensic scientists can determine from studying the WBCs? 7

What can each part tell us? 3. Red blood cells Carries gasses like oxygen and carbon dioxide through the body. Do not have a nucleus. What do you think forensic scientists can determine from studying the RBCs? 8

Red Blood Cells Determine Blood Type Antigen – a protein that can cause the body to make antibodies. Antigens found in the membrane of red blood cells account for blood types. There are 2 sets of antigens on the RBCs: ABO antigen and Rh antigen. 9

A and B Antigens The blood antigens come in two “flavors” A and B Based on your genes, you can have 1 of 4 types: 1. Just A antigen = A type 2. Just B antigen = B type 3. Both A and B antigens = AB type 4. Neither A or B antigens =O type. 10

RH Factor Did you ever wonder why some people have “+” blood and others have “-” blood? A+ A- B+ B- AB+ AB- O+ O- 11

RH Factor 85% of the human population has a second antigen called Rh factor on their red blood cells. Found from studying Rhesus monkey. Have it = “Rh positive” Don’t = “Rh Negative” A+ A- B+ B- AB+ AB- O+ O- 12

Practice Naming the Blood Types

Practice Naming the Blood Types

Practice Naming the Blood Types Rh B Rh Rh B B Rh Rh Rh B Rh B

Practice Naming the Blood Types Rh Rh Rh Rh Rh Rh Rh

Complete the First 2 Columns of the Blood Types Chart! Draw the RBC Antigens Present Reaction with A antibody Reaction with B antibody Reaction with Rh antibody A-

How Do We Determine Blood Types? Antibody – reacts with an antigen Every antibody reacts with only 1 antigen We can use it to identify antigens

How Do We Determine Blood Types? Everyone makes antibodies against blood antigens Only make them for antigens you do not have. If a person has A antigen on their RBCs, will they make A antibody? 20

How Do We Determine Blood Types? Agglutination- blood cells clump when an antibody recognizes the antigen. Because we can see this happening, we can figure out what antigens are present.

Practice Predicting Agglutination

Practice Predicting Agglutination B A B A A B B A A A B A B

Practice Predicting Agglutination B Rh B Rh Rh B B Rh Rh Rh B Rh B

Practice Predicting Agglutination Rh Rh Rh Rh Rh Rh Rh

Complete the Last 3 Columns of the Blood Types Chart! Draw the RBC Antigens Present Reaction with A antibody Reaction with B antibody Reaction with Rh antibody A-