Lab – Blood Vessels & Blood



Lab – Blood Total /20 marks

Background

Blood is classified as either type A, type B, type AB or type O depending on the presence or absence of antigens on the surface of our erythrocytes (red blood cells). These antigens are genetically inherited from our parents and may be proteins, carbohydrates, glycoproteins or glycolipids. Antigens are either classified as type A antigens or type B antigens.

Specialized white blood cells called plasma cells produce antibodies against antigens that are NOT present on our own erythrocytes. Antibodies, aka immunoglobulins (Ig) are glycoproteins that are found in the blood and some other body fluids. Antibodies are used by the immune system to identify and neutralize foreign invaders such as bacteria and also foreign blood cells that may have been received during a blood transfusion or organ transplant. Antibodies against A and B antigens begin to build up blood plasma shortly after birth and peak once we are approximately 8-10 years old. As we age, the number of antibodies in our blood declines.

|Blood Type |Antigen Present on Erythrocytes |Antibodies Present in Blood Plasma |Can Give Blood To |Can Receive Blood From |

|A |A |Anti-B |A, AB |O, A |

|B |B |Anti-A |B, AB |O, B |

|AB |A and B |Neither Anti-A nor Anti-B |AB |O, A, B, AB |

|O |Neither A nor B |Both Anti-A and Anti-B |O, A, B, AB |O |

• In Canada, approximately 42% of people have type A blood, 9% have type B blood, 46% have type O blood and 3% have type AB blood.

Importance of Blood Typing

People can only receive transfusions of only certain blood types, depending of the type of blood they have. If incompatible blood types are mixed, erythrocyte destruction, agglutination (clumping of erythrocytes) and other serious and life threatening problems such as kidney failure and shock can occur. When incompatible blood types are mixed the recipient’s antibodies will attack the incoming erythrocytes and cause them to agglutinate i.e. clump together. Agglutination occurs when the antibodies present in the recipient’s blood join together the “foreign” blood cells into large clumps. These clumps of erythrocytes then illicit a massive immune reaction and are attacked and destroyed by the recipient’s own immune system. These types of severe reactions are called acute hemolytic reactions. If the condition is not quickly treated, the recipient will likely die. Therefore, it is critical that compatible blood is used in a blood transfusion or organ transplant.

When a patient requires blood, a sample of their blood is typed and cross-matched by a lab technician to ensure the patient receives blood from a compatible blood donor. In the lab a technician mixes a sample of the recipient's serum with a sample of the donor's red blood cells and checks to see if the mixture agglutinates, or forms clumps. If agglutination occurs, that particular donor's blood cannot be transfused to the recipient. You can see agglutination in the diagram below.

People that have type O blood are said to be universal donors because their blood cells do not have A or B antigens on them. People with type AB blood are said to be universal acceptors, and can receive any recipient blood type because they do not have any antibodies in their blood plasma.

Purpose

1. To simulate the same procedures used in a medical laboratory to type and cross-match blood

samples of blood donors and recipients.

2. To use observe a prepared slide of blood.

Materials

|4 Blood typing Slides |Simulated Blood Samples: |

|8 Toothpicks |Mr. Smith |

|1 prepared slide of blood |Mr. Jones |

|Compound Microscope (400 x mag) |Mr. Green |

| |Ms. Brown |

| | |

| |Simulated Anti-A Serum |

| |Simulated Anti-B Serum |

Part 1: ABO Blood Typing

Procedure

1. Label each of your 4 blood typing slides with the following labels:

• Slide #1 – Mr. Smith

• Slide #2 – Mr. Jones

• Slide #3 – Mr. Green

• Slide #4 – Ms. Brown

2. Place 3 or 4 drops of Mr. Smith’s blood in each of the A and B wells of slide #1.

3. Place 3 or 4 drops of Mr. Jones’ blood in each of the A and B wells of slide #2.

4. Place 3 or 4 drops of Mr. Green’s blood in each of the A and B wells of slide #3.

5. Place 3 or 4 drops of Ms. Brown’s blood in each of the A and B wells of slide #4.

6. Place 3 or 4 drops of the simulated anti-A serum in each A well on the four slides.

7. Place 3 or 4 drops of the simulated anti-B serum in each B well on the four slides.

8. Obtain 2 toothpicks per blood typing slide. Stir each well with a separate clean toothpick for 30

seconds. To avoid splattering don’t press too hard.

9. Observe each slide and record your observations in table 1. in the results section of the lab.

10. Once observations are complete, wash all blood typing slides and toothpicks. The simulated

blood and anti-serum used in the lab is non-toxic and can be washed down the drain.

Results

Table 1. Blood typing results. (4 marks)

| |Anti-A Serum |Anti-B Serum |Blood Type |

| |Agglutination? |Agglutination? | |

|Slide #1 | | | |

|Mr. Smith | | | |

|Slide #2 | | | |

|Mr. Jones | | | |

|Slide #3 | | | |

|Mr. Green | | | |

|Slide #4 | | | |

|Ms. Brown | | | |

Key to Identifying Blood Types:

• If agglutination (clumping) occurs ONLY when the anti-A serum was added, the blood type is A.

• If agglutination (clumping) occurs ONLY when the anti-B serum was added, the blood type is B.

• If agglutination (clumping) occurs when a blood sample is tested with BOTH anti-serum A and anti-serum B, the blood type is AB.

• If NO agglutination (clumping) occurs when a blood sample is tested with BOTH anti-serum A and anti-serum B, the blood type is O.

Using your data from table 1. fill in table 2. which summarizes the antigen (agglutinogens) and antibodies (agglutinins) found in each of your simulated patients blood.

Table 2. Antigens and Antibodies in Blood of Simulated Patients (8 marks)

| |Antigen(s) |Antibodies |

|Slide #1 | | |

|Mr. Smith | | |

|Slide #2 | | |

|Mr. Jones | | |

|Slide #3 | | |

|Mr. Green | | |

|Slide #4 | | |

|Ms. Brown | | |

Part B – Observing Red and White Blood Cells

Background

The formed elements in blood include erythrocytes (red blood cells aka RBCs); several specialized leukocytes (white blood cells aka WBCs), and platelets. Erythrocytes are circular, biconcave disks that are approximately 5-8 μm in size; their shape makes them good at transporting respiratory gases, in particular oxygen (O2), as well as carbon dioxide (CO2). The number of circulating RBCs is closely related to the blood’s oxygen carrying capacity.

Leukocytes are larger that erythrocytes and range in size from 9-25 μm. The main function of leukocytes is to fight of foreign invaders such as bacteria, viruses, parasites, and cellular debris. Leukocytes are a unique type of blood cell because they are capable of moving against the current of the blood stream. This allows them to target infections and pass through blood vessel walls so they can enter tissues. A person’s normal WBC count normally varies from 5,000 – 10,000 WBCs / mm3 of blood. When a person has an infection, the body produces more WBCs to fight it therefore, doctors can order a WBC count to diagnose certain illnesses.

Procedure

1. Obtain a prepared slide of blood and put it on the stage of the microscope.

2. Lower the stage of the microscope and select the 10 X objective lens. Watch the stage carefully as you raise it towards your lens until you get a blurry image through the ocular lens. Use the fine focus knob to sharpen your image.

3. Switch to the high power (40 X) objective lens. Refocus ONLY USING THE FINE FOCUS KNOB. You risk smashing your slide and the microscope lens if you use the coarse focus knob.

4. Observe the red blood cells and white blood cells.

5. Using the blood cell poster, try to identify the type of WBC you see in the field of view.

Results

Look at blood under a compound light microscope and make a biological sketch of a RBC and a WBC and identify the type of WBC (use the blood poster to help you to identify the type of leukocyte). (3 marks)

Characteristics of a good biological drawing:

Drawings must have an underlined title, centred at the top of the page. The title must indicate the cell/tissue/organ type

The date of the assignment and your name must appear in the upper right corner of the page.

The drawing itself must be:

• Large

• Drawn just left of centre on the page

• Proportional such that all components of the drawing are proportional to the specimen itself

• Stippled to show contrast and detail. Shading must never be used.

• Drawn with a sharp pencil

• Very detailed and should not contain any artefacts.

Discussion Questions: (5 marks)

1. Could Mr. Jones donate blood to Mr. Smith? Explain.

2. Could Ms. Brown receive blood from Mr. Green, Mr. Jones or Mr. Smith? Explain.

3. What is a universal acceptor? Explain.

4. What is a universal donor? Explain.

5. Do mature RBC have a nucleus? Explain.

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