Download Lab 9: Blood Physiology - Francis Marion University

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Bio 235 Lab:
Part 1. Blood typing
Within our adaptive immunity, B lymphocytes produce antibodies (or immunoglobulins), which are designed specifically
against a foreign antigen (molecules on the surface of cells) that our immune system has detected within the body.
Antibodies bind to antigens and cause a cascade effect in the immune system that destroys the cells bound by
antibodies. The surface of red blood cells (RBC) contains a group of antigens that distinguish a blood type within the ABO
blood type system of humans. When an RBC antigen is detected by antibodies against that antigen the antibodies bind
to those antigens and cause RBC to clump together in a process known as agglutination.
Process of agglutination between RBC antigens and
antibodies against those antigens.
Blood typing test showing positive reaction
(+) and negative (-) reactions for
agglutination.
1. Blood type A has RBCs with A antigens (agglutinins) and anti-B antibodies. Anti-B antibodies in Type A blood will cross
react against the B antigens in Type B blood; thus, Type A people can receive blood only from Type A or Type O people.
2. Blood type B has RBCs with B antigens and anti-A antibodies. Anti-A antibodies in Type B blood will cross react against
the A antigens in Type A blood; thus, type B people can receive blood only from Type B or Type O people.
3. Blood type AB has RBCs with both A and B antigens but lacks any antibodies. Without these antibodies Type AB blood
will not cross react with either A or B antigens. Thus, Type AB people can receive blood from Type A, Type B, and Type O
people. This is why Type AB people are called “universal recipients”.
4. Blood type O has RBCs with no antigens. Thus, there are no antigens to cross react with either anti-A or anti-B
antibodies. Type O people can donate blood to either Type A, Type B, or Type AB people and they are called the
“universal donor”. However, Type O people can only receive blood from other Type O people. Fortunately, Type O blood
is one of the most common blood types (Table 2)
Rh factor (Rhesus factor) is one of the human blood group systems outside of ABO. The Rh blood group system consists
many antigen groups; however antigen D is the most important in determining potential cross-reactivity in blood
transfusions or hemolytic anemia in newborns. If someone is Rh- (neg) they lack the D antigen and if they are Rh + (pos)
they have the D antigen. For example, someone who is A- is Type A lacking the Rh D antigen. Likewise, someone who is
A+ is Type A having the Rh D antigen.
What antibodies does Type O blood have? __________________________
What antibodies does Type AB blood have? __________________________
What antigens does Type A blood have? __________________________
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How to Determine Your Blood Type:
1. Place two drops of blood into each of two wells of the blood typing card where indicated.
2. Add anti-A to one drop and anti-B to the other. [Be careful not to touch the tip of the bottle to your blood sample
because that would contaminate the bottle!]
3. Observe any agglutination in the samples and determine your blood type. _____________________
You and your instructor will summarize the blood types in the class according to table 2 below. How do the percentage
of blood types reported for the class compare with those reported in Table 3 below?
_______________________________________________________________________________
_______________________________________________________________________________
Table 2. Percentage of Blood Types in a Human Physiology Lab.
ABO & Rh Type
Actual Count / Class size
%
Total % without Rh
O+
OA+
AB+
BAB+
AB-
Table 3. Approximate incidence of blood types in USA (%).
Blood type
%
O+
37.4%
O-
6.6%
A+
35.7%
A-
6.3%
B+
8.5%
B-
1.5%
AB+
3.4%
AB-
0.6%
Total % without Rh
44%
42%
10%
4%
Source: Stanford School of
Medicine Blood Center
(http://bloodcenter.stanford.edu
/about_blood.htm)
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Part 2: Epidemiology
Epidemiology is the study of the source, spread, and control of disease in a population. Etiology is the source of a
disease outbreak within a population. An epidemic is defined as an increase in the occurrence of a disease over a given
time, within a specific area or affecting a particular population. The role of an epidemiologist is to collect pertinent
information about an epidemic – the causative agent, number of cases, the location and history of the disease,
contributing factors, etc. These details become valuable in controlling progression of the epidemic – whether it involves
development of a vaccine or other therapeutic agent, or the quarantine of infected individuals. Depending upon the
morbidity rate or mortality rate of the disease, strict measures may have to be implemented to control it. US public
health departments (e.g. CDC, NIH) are required to track and report many communicable diseases, e.g. avian flu,
cholera, hepatitis, syphilis, etc. Morbitity rate is the percentage of people that become sick from a disease within a
given population. Not everyone exposed to pathogens necessarily become ill. Mortality rate is the percentage of people
that die from a disease within a given population. In general, morbidity rate is always much higher than mortality rate.
For example the yearly morbidity rate for the common flu (influenza) in the United States ranges between 5 – 20%;
whereas the mortality rate for the flu is much lower at 0.02%*. Collectively, of all this epidemiological information is
critical in guiding the decisions of health care officials, like the Centers for Disease Control (CDC) in response to disease
outbreak. In this experiment, we will simulate an infectious epidemic in the class. Your objectives will be to (1) analyze
the source and transmission of the epidemic and (2) predict its impact on the class based on trends in its progression.
[*The Centers for Disease Control and Prevention (CDC), National Center for Health Statistics, Division of Vital Statistics ,
National Vital Statistics Reports (NVSR) Volume 61, Number 4, Table 19, May 8, 2013.]
Procedure
1. Each student is given a plastic Falcon tube (labeled with a number) that is filled with 14 ml of a clear solution that
represents his/her “bodily fluid”. Using a clean transfer pipette take half a dropperful of your fluid and add it to a
clean glass test tube (labeled 0) BEFORE you exchange fluids with another person. This will be your initial bodily fluid
sample.
2. When given the signal by the instructor, each student will use a clean transfer pipette to exchange ‘fluids’ with
someone at their table by putting a dropperful of his/her own solution from their Falcon tube into the other
person’s Falcon tube. Cap and mix your solution after the exchange. Each person should only make one contact
during this round and should record the name of the contact. [CAUTION: Avoid contact of the solution with skin. If
you do, rinse with water and wipe up any spills on table or floor.]
3. After this first exchange, add a half dropperful of your fluid to a clean glass test tube (labeled #1).
4. At the instructor’s signal, each student should find a second contact, exchange one dropperful of their Falcon tube
solution to another student’s Falcon tube, and record the name of the contact. Cap and mix your solution, and then
add half a dropperful of that solution to a clean glass test tube labled #2.
5. At the instructor’s signal, each student should find a third contact, exchange one dropperful of their Falcon tube
solution to another student’s Falcon tube, and record the name of the contact. Cap and mix your solution, and then
add half a dropperful of that solution to a clean glass test tube labled #3.
6. At the instructor’s signal, perform a fourth exchange. Your falcon tube will now serve as tube #4.
7. After 4 rounds are completed, you will add a diagnostic indicator to all test tubes (glass tubes 0, 1, 2, &3 and the
Falcon tube) to test for infection. The solutions of infected individuals will turn bright pink compared to the rest
which remain yellowish/orange.
[The diagnostic indicator is phenol red, which will turn an alkaline solution (pH > 8.2) bright pink.]
8. Pour out solutions in test tubes down sink, rinse well, and invert tubes upside down in rack to dry.
9. Working together as a class, try to analyze the spread of infection and answer the questions below.
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Table 1. Infections
Sample
0 = original body fluid
1 = first exchange
2 = second exchange
3 = third exchange
4 = fourth exchange
Had Contact With:
Questions
1. How many people were infected after
a. round 1?
b. round 2?
c. round 3?
d. round 4?
2. Can you predict the identity of the original infected individual?
Infected? Check the box:
YES
NO