Download Blood and Blood Cells - Tamalpais Union High School District

Physiology 2
Name
Redwood High School
Class Period
Blood and Blood Cells
Background
Blood is a connective tissue that is characterized by blood cells that are located in a liquid matrix. The
liquid matrix allows blood to move, flowing through the cardiovascular system to deliver nutrients and
oxygen to the body cells while removing wastes and carbon dioxide. The liquid matrix is called plasma
and makes up about 55% of the total blood volume. The cellular components – collectively called the
‘formed elements’ – make up the remaining 45% of the blood. These formed elements include two types
of cells – erythrocytes (red blood cells) and leukocytes (white blood cells) – along with cellular fragments
known as platelets.
Red blood cells – erythrocytes – make up about 99% of all blood cells. They are responsible for gas
transportation, oxygen to the cells and carbon dioxide away from the cells. This means that a normal
human will have between 4 million and 6 million red blood cells per cubic millimeter of blood (4,000,000
– 6,000,000/ mm3). These cells are formed in the bone marrow and lack a nucleus when they are mature.
As a result, mature red blood cells cannot reproduce and they have a limited life. Old red blood cells are
broken down in the liver.
In a healthy individual, leukocytes make up less than 1% of all blood cells. A healthy human will
typically have between 5,000 and 10,000 leukocytes per cubic millimeter of blood. The white blood cells
are a principal component of the immune response. As a result, their numbers will change in response to
infection or disease. This makes the white cell count an important diagnostic tool. At the cellular level,
there are five (5) observable types of leukocyte: neutrophils; basophils; eosinophils; monocytes and
lymphocytes. These five varieties are characterized by appearance of the nucleus, size and staining
properties. Each is responsible for a specific aspect of the immune response.
Platelets, or thrombocytes, are small fragments of cytoplasm that form from large cells (called
megakaryocytes) in the bone marrow. Because they are not technically cells, they are referred to as
formed elements. They make up less than 1% of the formed elements. A normal individual has 150,000400,000 platelets/ mm3 of blood. Platelets are responsible for blood clotting, also know as hemostasis.
In this lab, we will observe all three formed elements, including the five types of white blood cell. We
will also look at the difference between normal blood and a several forms of abnormal blood.
Focus Questions
• What are the different formed elements in blood and how are they identified microscopically?
• What are the different types of leukocyte and how are they identified microscopically?
• What are some examples of abnormal blood and how are they different from normal blood?
Procedure
Part A. Observing Erythrocytes, Leukocytes and Platelets
1. Obtain a prepared blood smear from the "normal" slide tray.
2. Observe the slide using 100x and 400x magnification. Use diagrams and information from your
textbook to identify each of the five white blood cell types.
3. Make an accurate biological drawing of a field of view that contains one example of a granulocyte.
Label the following structures: red blood cell, platelet, name of granulocyte (neutrophil, basophil,
eosinophil), granulocyte nucleus; granulocyte cell membrane; cytoplasmic granules. Measure the
diameter of the granulocyte. Write a brief description on the function of the leukocyte type you have
drawn. You will be graded on your identification and the accuracy of your measurements.
4. Make an accurate biological drawing of a field of view that contains one example of an agranulocyte.
Label the following structures: red blood cell, platelet, name of agranulocyte (monocyte or
lymphocyte), agranulocyte nucleus; agranulocyte cell membrane. Measure the diameter of the
agranulocyte cell. Write a brief description on the function of the leukocyte type you have drawn.
You will be graded on your identification and the accuracy of your measurements.
Part B. Differential White Cell Count
1. Focus on the cells at one end of your blood smear using the 400x objective.
2.
3.
4.
5.
Using the mechanical stage, move the slide back and forth slowly, following a path that avoids
passing over the same area twice.
Each time you encounter a leukocyte, identify it and record as a tally in the data table below.
Continue searching for and identifying leukocytes until you have recorded 100 cells in the data table.
The percentage of each cell type is equal to the total number of each type of white blood cell that you
counted.
Complete the data table by researching the normal percentage for each leukocyte.
Part C. Pathological Blood Smears
1. Obtain a blood smear from the "pathological" slide tray that indicates a pathological condition of red
blood cells.
2. Observe the slide under both 100x and 400x objectives, with special attention to differences in the red
blood cells.
3. Make a qualitative written observation of your slide. Focus your observations on structural
differences between the normal blood smear (from part A) and the pathological blood smear.
4. Obtain a blood smear from the "pathological" slide tray that indicates a pathological condition of
leukocytes.
5. Observe the slide under both 100x and 400x objectives, with special attention to differences in the
leukocytes.
6. Make a qualitative written observation of your slide. Focus your observations on structural
differences between the normal blood smear (from part A) and the pathological blood smear.
Analysis and Conclusion
1.
Describe the structure and function of red blood cells.
2.
Describe the structure and function of platelets.
3.
Briefly summarize the functional role of each leukocyte type. Be sure to specifically identify its role in
the immune response.
4.
Do some additional research on one of the blood disorders you described in Part C. What aspects of
the blood are abnormal and how do these abnormalities affect the person? In other words, what is the
relationship between abnormal structure of the blood and abnormal function of the patient?