Human Anatomy and Physiology. Frolich, Page 4

Human Anatomy and Physiology. Frolich, Page 4

Blood Lab Instructions and Wish List

Blood Lab

MY NAME: ______

MY BLOOD SAMPLE #:_____ (from microscope slide—use same tube slot in centrifuge)

Goals for this activity:

1.  Safely acquire and analyze a sample of a few drops of blood

2.  Use a centrifuge to separate out the components of blood, including hematocrit. Understand why that works and what you are seeing in the capillary tube with your blood in it.

3.  Type your own blood and appreciate what blood type means in regard to the antigens on your blood cells and what types of donors can be used for transfusions to what types of recipieints.

4.  View your own blood under the microscope and identify its various cellular components.

Getting the Blood—Finger Prick

You will need three drops of blood for three purposes

·  Hematocrit—to see volume of cells and plasma in your own blood

·  Blood smear—to view your own blood under microscope

·  Blood typing—to see antigen reactions for typing your own blood (A,B,O,Rh)

Be sure you have the following ready before you prick your finger

·  Sterile lance

·  Alcohol pad

·  Hematocrit or capillary tube

·  Two microscope slides (for smear)

·  Blood typing card

·  Helper wearing gloves

Read the entire lab, get everything ready and then do these steps quickly in this order:

1.  FINGER PRICK: Wipe with alcohol, let dry, prick with lance—use side of fourth finger.

2.  DROP ON MICROSCOPE SLIDE. Apply blood to microscope slide and smear with other slide as shown below—best to watch video on course website first.

3.  HEMATOCRIT TUBE. Touch hematocrit tube to drop on finger so that capillary action sucks it into tube. Then, holding pricked finger over end of tube, press other end into “play-dough” capping material to cap tube. Give tube to helper—only helper should wear gloves.

4.  DROPS ON TYPING CARD: Apply three blood drops to blood typing card. Have helper add Anti-A, Anti-B and Anti-D (Rh) reagents and mix right away. Use a separate toothpick to mix each reagent with the blood on the card. Read results in two minutes.

5.  STOP BLEEDING. Wipe again with alcohol swab and then cover with cotton gauze or band-aid if needed.

Part I: Blood Typing

For two minutes after mixing, watch for agglutination or clumping of your blood/reagent mixture and record your results:

Anti-A Serum Anti-B Serum Anti-D (Rh) Serum

Then compare to determine what type of blood you have. Blood type: ______

Please be sure you understand, based on what kinds of antigens are made by each kind of blood, why you get the agglutination reactions for each blood type. Appreciate why Type O are universal donors and Type AB are universal recipients.

ABO Blood typing is clinically important because if an antigen and an antibody of the

same letter are mixed an agglutination reaction will occur. For example, if a patient

with A antigen on the surface of their RBCs receives a type B blood transfusion

(containing anti-A antibodies) the donor cells will clump together (agglutinate). This

clumping is called a transfusion reaction and the clumped cells can clog small blood

vessels cutting off blood supply to different regions of the body. As some of the RBCs

begin to break down due to the action of phagocytes, hemoglobin is released and may

block kidney tubules leading to kidney failure. Furthermore, ruptured RBCs can no

longer carry O2. If the reaction is severe enough, the patient receiving this mismatched

blood transfusion can die.

Rh blood typing is also important as once an individual receives mismatched blood (e.g.

an Rh- patient receives Rh+ blood), the patient will develop anti-D antibodies which will

lead to a transfusion reaction if this same mistake is ever repeated. The most common

concern, however, is erythroblastosis fetalis. In this case, an Rh- mother carrying an

Rh+ baby may produce anti-D antibodies if some of the fetal blood crosses the placenta

and enters her circulation. Upon a second pregnancy with an Rh- fetus, the anti-D

antibodies can cross the placenta and destroy the fetal RBCs leading to fetal death. To

prevent this, all Rh- mothers are given RhoGAM, a serum derived product, which can

block the mother’s immune system from generating anti-D antibodies by agglutinating

the Rh factor that enters her blood stream. It is therefore given to pregnant mothers who

experience bleeding, at about 28 weeks of pregnancy, and within 72 hours after a birth,

miscarriage, abortion, or amniocentesis.

Part II: Hematocrit

This is the normal % of erythrocytes in a whole blood sample. RBCs normally make up

~45% of the total volume of a blood sample. Leukocytes make up less than 1% of the

total sample. Plasma makes up the rest of the volume (~55%). These percentages can be

determined by centrifuging a sample of whole blood which will cause the red blood cells

to settle to the bottom.

1.  Put your tube in the same slot as the number on your microscope slide. All samples from the whole class can be spun at once. Spin the tubes in the centrifuge for about five minutes.

2.  Estimate the percentage of blood volume that is RBC’s or erythrocytes—this is your hematocrit. Can you see a coat of leukocytes or “white blood cells?”

Part III: Blood Smear under Microscope

1.  Stain your blood smear with a drop or two of Wright’s stain.

2.  Observe the slide under the microscope highest power. You can even use the oil lens to get great views of the cells. Ask for help if you have not done this before.

3.  Be sure you identify all the cell types:

a.  Erythrocytes or RBC’s—most abundant cells

b.  Platelets: are these really cells?

c.  Leukocytes or white blood cells—granulocytes (have distinct granules) and agranulocytes (with indistinct granules)

DISTINCT GRANULES

Neutrophils: Most numerous WBC’s. Multi-lobed nucleus, pale cytoplasm, fine granules. (considered neutral because they take up both acidic and basic stains). Immunologically, these are active phagocytes.

Eosinophils: Less numerous and hard to find…let others know if you find one. Bi-lobed nucleus, reddish/orange granules in the nucleus, stains red because absorbs acidic stain eosin. These phagocyte-type cells are involved mostly in immune signaling and will burst releasing signal proteins. Also involved in allergic and inflammatory responses.

Basophils: Least numerous and harder to find…let others know if you find one. Nucleus large and U-shaped, absorbe basic-staining dye and have large bluish-black granules with histamine. Also contain heparin.

WITHOUT DISTINCT GRANULES

Lymphocytes: Most numerous of agranulocytes and second-most common WBC’s (after neutrophils). Nucleus is large and round and fills cell. Most lymphocytes are outside blood in lymph tissues. These are the B-cells and T-cells of the specific immune response.

Monocytes: Largest WBC’s. Kidney-shaped nucleus and light gray-blue cytoplasm. Wandering phagocytes that can leave blood and move into tissues. Can become fixed macrophages in tissues (e.g. Langerhans cells in skin or microglial cells in CNS)

Wish List for Blood Lab

FROM BLOOD TYPING

·  Antigens: A, B, D (Rh)

·  Antibodies: Anti-A, Anti-B, Anti-D (Rh)

·  Blood Types: A, B, O, Rh+/-

·  Agglutination reactions

·  What blood types are compatible?

·  What happens when someone is given blood from a non-compatible donor?

·  When is Rh factor (+/-) most important and why?

FROM HEMATOCRIT

·  Percentage or fraction

·  Hematocrit—normal range

·  Plasma, WBC’s or “buff coat”

·  What might affect hematocrit?

·  How does centrifuge separate out components of blood?

FROM BLOOD SMEAR

·  Erythrocytes or RBC’s

·  Platelets

·  Leukocytes or WBC’s

o  Neutrophils

o  Eosinophils

o  Basophils

o  Monocytes

o  Lymphocytes

·  Know each WBC function in immune response