Download Cells of the Body

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Cells of Your Body
BACKGROUND INFORMATION:
Cells come in a variety of shapes and sizes. Typical cells range from 5 to 50 micrometers.
Despite the difference in sizes, all cells have two characteristics in common. They are all
surrounded by a cell membrane and all cells contain genetic material.
Cells in multicellular organisms are specialized in their functions. Because of this
specialization, cells may have different structures that allow the cell to carry out its special
function. For example, skeletal muscle cells are packed with fibers arranged in a tight, regular
pattern. When the cells contract, they use chemical energy to pull the fibers past each other, thus
generating a force. This allows the movement of body parts.
Cells that are similar in function are grouped together in tissues. Tissues specialize in their
function. For example, skeletal muscle cells group together to make skeletal muscle tissue. This
tissue is usually attached to bones and allows for the movement of the bones.
Epithelial Cells
Epithelial cells form epithelial tissue. This tissue covers the outside of the body and lines organs and
cavities. The tissue is a thin layer of closely packed cells that act as a barrier that protects against
injury, invading microorganisms and loss of fluid.
Color the Examples of epithelial cells seen below. A1 represents the squamous cells that are found
lining the body’s surface and protecting against dehydration. A2 are columnar cells which are found
in the digestive tract and absorb nutrients, notice the villi which increase their surface area and allow
them to absorb nutrients more efficiently. A3 are cuboidal cells, they can be found lining your kidneys
and other glands. Color and label the cell membrane, nucleus, cytoplasm and cilia on the epithelial
cells below.
Blood Cells
Blood contains red blood cells (D10) which specialize in
carrying oxygen and carbon dioxide, white blood cells
(D11) which act as the bodys defense system, engulfing
bacteria and other harmful organisms and producing
antibodies. Blood also contains platelets (D12) which aid
in blood clotting.
Bone Cells
Bones contain both living and nonliving materials. Bone is made of living cells called osteocytes that
are surrounded by nonliving materials such as calcium phosphate. Canals in the bone allow nerves
and blood vessels to run through the bone. Notice the circular-pattern units. Each of these units has
a central, hollow core called a Haversian canal. This canal contains blood vessels and nerve cells.
The rings around the canal contain small, darkly stained bodies. These are the living bone cells
called osteocytes. Notice the fine branches extending from the
osteocytes into the matrix around each osteocyte. These branches
are made of collagen and calcium phosphate that have been
deposited into the matrix by the osteocyte. These deposits are what
makes a bone hard, not brittle.
Color one of the concentric circles with the osteocytes and calcium
deposits. Label the Haversian canal and osteocyte.
Muscle Cells
There are three types of
muscle tissue in the human
body: skeletal, smooth,
and cardiac muscle tissue.
Skeletal muscle tissue is
attached to and allows the
movement of bones.
Skeletal muscle appears to
have alternating bands of
light and dark striations. The
skeletal muscle cells are
also multinucleated. Smooth
muscle tissue lines the walls
of the digestive tract and
some blood vessels in the
circulatory system. Smooth
muscle tissue is spindle
shaped and the cells contain
only one nucleus. Cardiac
muscle tissue is only found
in the heart. Cardiac muscle
tissue is striated like skeletal
muscle tissue, but the cells
only contain one nucleus like
the smooth muscle cells. Fill
in the key below the diagram
(you pick the colors) and
color the different muscle
cell types.
Nerve Cells
Neurons make up nervous tissue. Neurons are uniquely designed to conduct an impulse. They
sense stimuli and transmit this information from one part of the body to another. Neurons consist of a
cell body surrounded by dendrites that pick up the stimuli. The stimulus passes from the dendrites
through the cell body. The stimulus then passes down the axon away from the cell body.
color the neuron. Label the cell body, nucleus, dendrites, and axon. Draw an arrow to show the
direction a message travels in a nerve cell.
Review Questions
What two characteristics do all cells share?
What do we call a group of specialized cells?
How does the structure of columnar epithelial cells relate to their function?
What types of cells are found in your blood? What do each of these cell types do?
What is the function of the:
Haversian Canals?
Osteocytes?
What chemical element gives bones their strength?
Athletes tend to have a greater number of mitochondria in their skeletal muscle cells, why do you
think that is?
In what part of the body can smooth muscle be found?
.
In what part of the body can cardiac muscle be found?
How is a cardiac muscle cell similar to a skeletal muscle cell?
How is a cardiac muscle cell similar to a smooth muscle cell?
Choose 1 of the specialized cell types and explain in how its structure relates to its function.
You have found an unknown cell type and discover that it contains an unusually high amount
of smooth endoplasmic reticulum what do you think its function might be? Explain your
answer.