1. BIO 127: Anatomy and Physiology I MSU – College of Technology
Chapter 6: Cardiovascular System: Blood
Relating Cell Structure to Function
Background:
Blood is composed of cells, cell fragments, and fluid plasma. In this lab, you will relate the structure of specific blood cells to the
function each performs.
Objectives:
In this activity you will
• observe blood cells.
• relate cell structure to function.
• identify the primary cells that are responsible for providing the body’s immune response.
Materials:
• prepared slide of human blood (use the figures instead of an actual slide)
• compound light microscope (the figures are magnified as they would be through a microscope)
Procedure:
1. If available, examine a prepared slide of human blood under low power of the microscope. Change the position of the slide
and continue your examination.
2. Switch to high power and focus clearly on the cells. The most numerous cells are called red blood cells. Make a detailed
drawing that shows a number of red cells. Label the parts of the cell that you recognize. Record your observations of the size,
shape, and the relative number of the red cells. Since you don’t have access to a microscope, refer to Figure 1.
Figure 1
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2. 3. Slowly move the slide until you find one or more larger cells that appear very different from the red cells. These cells are
called white blood cells. Make a drawing of the white blood cell. Label the parts of the cell that you recognize. Record your
observations of the size, shape, and relative number of white blood cells. Refer to Figure 1 and Figure 2 for these
observations.
Figure 2
4. Look for evidence of tiny, dot like cell fragments called platelets. Make a drawing of a few platelets. Record your
observations of the size, shape, and relative number of platelets. Return to Figure 1 for these observations.
Background
The immune system is the body’s way of avoiding infection and attach by pathogens like bacteria and viruses. It consists of a
specialized series of vessels (the lymphatic system) along with a number of different specialized cells that defend the body against
attack. The lymphatic system also has functions that support the activity of the cardiovascular system. Immunity is brought about by
the activity of several organs as well as a number of specialized cells that circulate throughout the body providing protection from
infection. In this lab, we will focus on the immune cells,
There are a variety of different cells that circulate through the blood and lymph and serve to remove pathogens from the blood. The
immunity primarily depends on the activity of various types of white blood cells. There are five types of cells we are interested in:
1. Neutrophils
2. Monocytes
3. Eosinophils
4. Basophils
5. Lymphocytes
Neutrophils are make up the majority of the circulating white blood cells. These cells consist of a darkly stained nucleus, often
consisting of multiple lobes attached by small strands, like pearls on a string. These are the first cells to arrive at injuries, attacking
bacterial cells that have been marked with antibodies, and engulfing them by phagocytosis. Neutrophils are also sometimes called
PMNs.
This image shows many red blood cells with two large neutrophils in the center of the image. The small blue circles that are smaller
than the erythrocytes are platelets.
Monocytes are large cells with large, horseshoe-shaped nuclei. These cells circulate for brief periods of time, before entering the
peripheral tissues to be come macrophages. A macrophage is a cell that attacks pathogens by phagocytosis, releasing chemicals that
stimulate the activity of other immune cells. These cells make up about 8% of the circulating white blood cells.
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3. This is an image of a monocyte. Note its dark purple, horseshoe-shaped nucleus
Eosinophils are similar in size to neutrophils, but they possess a bilobed nucleus, and they tend to have small, darkly stained granules
visible. Depending on the stain that has been applied, the granules may appear bright red. Eosinophils attack objects that have been
coated with antibodies and engulf them by phagocytosis or secrete toxic compounds that kill the invading cell. They also defend
against multicellular invaders, such as parasitic worms and flukes. These cells are relatively rare, making up about 2% of the
circulating white blood cells.
This image shows an eosinophil (note the granules inside the cell and two lobes of the nucleus). There is also a small lymphocyte
below it.
Basophils are cells that contain large, dark granules and a large nucleus. These cells are rather rare, only accounting for
approximately 1% of the circulating white blood cells. Basophils migrate to injury areas and release histamine and heparin, chemicals
that enhance the inflammatory response. They also release chemicals that attract other immune cells. This image shows a basophil in
the center. It has a lobed nucleus and many large, dark granules inside. A neutrophil is visible to the left and a lymphocyte is visible
to the right.
Lymphocytes are the second most common white blood cells, making up about 30% of the circulating cells. Many of the
lymphocytes are involved in the body’s specific defenses, providing immunity to specific pathogens. Lymphocytes continually
circulate from the blood stream, through the tissues and back into the blood. There are three types of lymphocytes, T cells, B cells,
and natural killer cells.
This image shows a lymphocyte on the left and a neutrophil on the right.
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4. This picture shows all the white blood cells covered in this lab.
A E
D
C
B
F
Identify each one:
A _____________________________
B _____________________________
C _____________________________
D _____________________________
E _____________________________
F _____________________________
Analysis:
1. The transport of oxygen throughout the body is one important function of blood. What evidence suggests that this function
would be better performed by red blood cells than by white blood cells?
2. What evidence suggest that only white blood cells are capable of reproducing?
3. The capture and destruction of foreign organisms, such as bacteria, is another function of blood. What evidence suggests that
whit blood cells are better suited to this function that red blood cell?
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