Blood lab (Exercises 34)Answers

The background information for understanding today's Blood lab is found in the Blood lectures of our Bio 11 course. So before you do today's lab, I highly recommend that you (a) Watch the Blood lecture videos on the course's YouTube channel (these blood lecture videos are titled LectureE31Blood1, LectureE32Blood2, and LectureE33Blood3), (b) Read the Blood lecture outline and use it to take notes as you watch the Blood lecture videos, and (c) Do the Blood review questions on the course website.

Today’s blood laboratory has four activities. Experiment 34 in the lab manual has some background information on these labs, but use the procedures below for today’s activities, not the procedures in the lab manual.

1) Blood microscope slide viewing and sketchingBlood cells are called the “formed elements.” The 3 major types of blood cells are red blood cells, white blood cells, and platelets. In this activity you will learn to identify the major blood cell types by viewing and sketching them under the microscope. Refer to figure 34.1 and table 34.1 in your lab manual for help in identifying the various types of blood cells.

a) Open the microscope cabinets below your lab bench and place the microscope on your bench top.

b) Obtain a prepared blood slide and view it under your microscope. Blood cells are small and hard to bring into focus. Ask your instructor for assistance in focusing.

c) The most numerous blood cells are red blood cells (also called RBCs or erythrocytes). RBCs’ main function is to carry oxygen throughout the body. Under the microscope, red blood cells appear as small pink circles with no nucleus. In the results table below for this section, sketch a red blood cell.

d) White blood cells (also called WBCs or leukocytes) are the cells of the immune system. Under the microscope, WBCs appear as cells with a large dark blue nucleus. There are five different types of WBCs. The two most numerous types of WBCs are called neutrophils and lymphocytes.

1) Neutrophil WBCs have an irregularly shaped nucleus that usually has 2 – 5 lobes. Identify one neutropil WBC and sketch it in the results table.

2) Lymphocyte WBCs have a large nucleus that is either round or kidney bean

shaped. Identify one lymphocyte WBC and sketch it in the results table.e) Platelets are blood cells that are involved in blood clotting. They are the smallest of the blood cell types. In fact, even under the highest magnification of your microscope, platelets will appear only as small spots between the much larger RBCs and WBCs. Identify a platelet and sketch it in the results table. f) After you have viewed. Sketched, and labeled the blood cells in the slide, answer the following questions:

1) Red blood cells are also known as Erythrocytes (one word). The function of RBCs is to Carry oxygen. RBCs are filled with a protein called Hemoglobin that helps them perform their function. Unlike most cells in the body, RBCs do not have a Nucleus (an organelle).

2) There are 5 (a number) major WBC types. The two most numerous of the WBC types are the Neutrophils and the Lymphocytes. Of the two answers that you wrote above, circle the one that has a large round nucleus. Put a star on the one that has a lobed nucleus. [Lymphocytes circled and Neutrophils starred]

3) The smallest of the formed elements are the Platelets. The function of this blood cell type is . Blood slide viewing results table. In the box below, sketch (a) one RBC, (b) One

neutrophil WBC, (c) One lymphocyte WBC, and (d) One platelet. Label the name of each of the four cells in your sketch.

2) The hematocrit blood testThe hematocrit blood test is a test that is often done on blood samples to see if the patient has the normal amount of RBCs in their blood. A below normal hematocrit would suggest that the patient has anemia due to too few RBCs. In today’s lab, you will perform a hematocrit test on sheep’s blood.

a) Obtain a capillary tube (a long and thin hollow glass tube).

b) On the front desk, there is a small test tube containing a specimen of sheep blood. Place your capillary tube into the sheep blood test tube, then slowly tilt the sheep blood test tube until it is horizontal. The blood should flow into the capillary tube. Try to fill almost all of the capillary tube with blood. When the capillary tube is almost full, keep it horizontal but slide it out of the sheep blood test tube.

c) Locate the small box containing clay. Plug one end of the capillary tube by gently pressing it into the clay.

d) Place the plugged capillary tube into the centrifuge machine. Be sure that… 1) The plugged end is facing the outside of the centrifuge.

2) You write down the number your tube’s slot.3) There is a tube opposite yours to balance the centrifuge4) The lid is on the rotor before you start the machine.

e) Centrifuge the blood samples for 3 minutes.

f) After the centrifuge has stopped, remove your blood sample and inspect it. It should have a red layer (red blood cells) at the bottom of the tube. There should be a clear liquid layer (plasma) on top of the red layer).

g) Obtain a ruler. Using the millimeters units on the ruler, measure the size of the RBC layer and the size of the entire blood sample (from the bottom of the RBC layer to the top of the plasma layer).

h) The hematocrit of a blood sample is defined as the percent of the total blood volume that is RBCs. In terms of your measurements,

mm RBC volumeHematocrit = ---------------------------- x 100.

mm total blood volume

Normal hematocrit value for humans is around 45%. Males usually have a slightly higher hematocrit than females.

i) Record the blood sample hematocrit here: 44 %. Show your instructor your results when you complete this step. [The 44% is from the 35 mm RBC volume divided by the 79 mm total blood volume in the capillary tube shown in the lab results video.]

j) Review questions on hematocrit: Answer each of the following hematocrit review questions:

1) What is the definition of hematocrit: Hematocrit is the percentage of the total blood volume that is RBCs.

2) What is the normal hematocrit percentage for humans? 45 %.

3) If a patient drank a lot of water just before giving blood for a hematocrit test, you would predict that their hematocrit percent would be above/below/equal to a normal hematocrit percentage (circle one of the three possible answers).

"Below" circled. The plasma is the watery part of the blood, so drinking water increases the total blood volume by increasing the plasma but drinking water does not increase the number of RBCs. A hematocrit capillary tube with larger blood volume but normal RBC volume would have a lower hematocrit percentage than normal blood.

4) If a patient donated a lot of blood just before giving a blood sample for a hematocrit test, you would predict that their hematocrit percent would be above/below/equal to a normal hematocrit percentage (circle one of the three possible answers).

"Equal" circled. Blood is made of plasma and blood cells. Therefore, when a person donates blood, they are lowering the amount of the plasma and also the amount of blood cells that they have in their body. Because donating blood lowers the plasma and also lowers the blood cells, the ratio (the relative amounts) of plasma to RBC in the person's body does not change. So the hematocrit capillary tube would not show any change in the ratio (the relative amounts) of RBCs to plasma, so the hematocrit percent would be normal.

5) If a patient moved to Colorado, where the body makes more RBCs because of the low oxygen levels, and then gave a blood sample for a

hematocrit test, you would predict that their hematocrit percent would be above/below/equal to a normal hematocrit percentage (circle one of the three possible answers).

"Above" circled. Blood is made of plasma and blood cells. If the body made more RBCs, that would increase the RBCs but it would not increase the plasma. A hematocrit capillary tube with larger RBC volume but normal plasma volume would have a higher hematocrit percentage than normal blood.

3) Determining your own blood type

This activity involves working with human blood. Blood is considered a biohazardous substance. Observe the following safety rules throughout the entire period.

• Only work with your own blood and instruments.

- Do not assist anyone else in puncturing their skin

- Do not handle anyone else’s instruments or materials

• Place an absorbent pad on your own workspace. Do all of your blood work over this pad.

• Clean up your work area when done. No wastes go into the regular trash.

- Dispose of all wastes that are sharp (lancets, capillary tubes, toothpicks, etc) into the “Sharps” biohazard container.

- Dispose of all soft wastes (paper towels, absorbent pads, alcohol pads, blood typing cards, etc.) in the round buckets biohazard buckets

Recall that there are eight possible human blood types: A+, A-, B+, B-, AB+, AB-O+, and O-. The goal of this activity is to determine which one of those eight is your own blood type.

a) Obtain the following materials from the front desk: A cotton pad, a blood typing card, three toothpicks (blue, yellow, and white), an alcohol pad, and a paper towel.

b) On the front desk are three droppers: Blue, yellow, and white. Place one drop of the blue in the first section of the blood typing card, place one drop of the yellow in the second section of the blood typing card, and place one drop the white in the third section of the blood typing card.

The blue drop contains anti-A antiserum (antibodies that can bind to the A antigen). The yellow drop contains anti-B antiserum (antibodies that can bind to the B antigen). The white drop contains anti-Rh antiserum (antibodies that can bind to the Rh antigen).

c) Place the cotton pad on your desk with the blood typing card in the middle of the pad. Next, ask your instructor for a lancet. A lancet is a device used to make a small puncture in the skin. It is a spring-loaded needle inside a plastic housing.

d) In this step, you will puncture your finger with the lancet. First, remove the safety cap from the lancet. Next, sterilize your finger with the alcohol pad. Lastly, push the lancet against your finger, This will cause the lancet to make a puncture in your skin.

e) Put one drop of blood next to each of the three colored antiserum drops on the card.

f) Using the correct color-matching toothpick for each drop, mix each blood drop with the antiserum by stirring with a toothpick.

g) After all three blood drops have been stirred, inspect each stirred drop.

- If the stirred blue drop appears agglutinated (grainy) your RBCs contain the A antigen. If the blue drop does not appear agglutinated, your RBCs do not contain the A antigen.

- If the stirred yellow drop appears agglutinated (grainy) your RBCs contain the B antigen. If the yellow drop does not appear agglutinated, your RBCs do not contain the B antigen.

- If the stirred white drop appears agglutinated (grainy) your RBCs contain the Rh antigen. If the white drop does not appear agglutinated, your RBCs do not contain the Rh antigen.

h) Using the reactions on the card, record your blood type here: B+(Have your instructor inspect your card to confirm your blood type analysis. )i) Clean up: Dispose of the lancet and the toothpicks in the sharps biohazard waste. Dispose of all other materials in the soft biohazards waste. Nothing goes in the regular trash.

j) Answer these review questions on blood typing:1) Which antigen(s) are on the surface of RBCs of blood type…

A+ = A and Rh antigens AB- = A and B antigens B- = B antigen AB+ A, B, and Rh antigensA- = A antigen O+ = Rh antigenB+ = B and Rh antigens O- = (No antigens)

2) Name the blood type indicated by the following reactions on a blood typing card:

A+3) Which of the eight blood types is the most common? O+

4) The computer blood typing and transfusion simulationa) Obtain a computer and open the internet browser. Play the blood typing/transfusion simulation game by navigating to the following website:

https://educationalgames.nobelprize.org/educational/medicine/bloodtypinggame/

b) At the above website, click the link that says "Play the Blood Typing Game". The select the version of the game that says Quick Game - Random Patients. For each of the three virtual patients, you first find their blood type and then you give them all of the safe transfusion blood types (and avoid giving them any unsafe transfusion blood types).

c) When you have completed the computer blood typing/transfusion simulation, do the following review questions:

1) There are eight possible blood types. List them all:A+, A-, B+, B-, AB+, AB-. O+, O-

2) If a patient has blood type A+, which of the eight blood types could they always safely receive? A+, A-, O+, O-

3) If a patient has blood type AB+, which of the eight blood types could they always safely receive? A+, A-, B+, B-, AB+, AB-. O+, O- (all 8 blood types)

4) If a patient has blood type B-, which of the eight blood types could they always safely receive? B- and O-

5) If a patient has blood type O+, which of the eight blood types could they always safely receive? O+ and O-

6) If a patient has blood type O-, which of the eight blood types could they always safely receive? O- only

7) Which blood types is the “universal donor”? O-

8) Which blood type is the “universal recipient”? AB+

Safety procedures for working with human blood in the laboratory

1) Each student will work only with their own blood sample. A student may not assist another student in puncturing skin, drawing blood, working with blood samples, cleaning work area, disposing of materials, or any other activity where blood is handled. Students are not permitted to enter another student’s work area when blood work is being done.

a) The instructor will not provide any bloodwork-related equipment or materials to students who are present in the laboratory but not working with blood.

2) Work areas (such as laboratory bench tops) that will be used for blood work will be covered with a disposable absorbent material for the duration of the work. Students will work with their blood only in their own work area and are responsible for cleaning that work area, lancet pens, and other equipment contaminated with only their own blood, and for disposal of their own blood work supplies.

a) The instructor is responsible for cleaning blood on shared areas and shared equipment (such as the centrifuge, the hematocrit reader, and the capillary tube sealer) and for cleaning any blood of unknown origin.

b) Any blood on shared areas, shared equipment, or outside of the student work area will be cleaned immediately.

3) All disposable materials that have contacted blood or could reasonably be assumed to have contacted blood are to be considered biohazardous materials and must be disposed of in special containers as outlined below:

a) Soft materials (such as absorbent pads, paper towels, dressings, gloves, gauze, and cotton balls) must be placed in a labeled biohazard bag and autoclaved. The bag must be taped whenever transported.

b) Sharp materials (such as lancets, needles, toothpicks, capillary tubes and other disposable glass) must be placed in a labeled plastic biohazard container immediately after use and autoclaved. The container lid must be closed whenever transported.

c) Broken, contaminated glassware must not be handled directly with hands, but must be cleaned up by mechanical devices such as brush and dustpan or forceps.

4) Surfaces and non-disposable equipment that have contacted blood or could reasonably be assumed to have contacted blood are to be cleaned and decontaminated using a solution capable of sterilizing/disinfecting the surface/equipment (such as hydrogen peroxide, staphene, or 1:10 diluted bleach solution).