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What Is a Tissue?
What Is a Tissue?
Close your eyes and picture your school. It is probably a building
with many different rooms. Each room has a special use. You eat in
the cafeteria. You read books in the library. Together, all the
separate rooms make up your school. A multicellular living thing
is set up in a similar way.
Multicellular living things are made of many cells. All people,
plants, and animals are multicellular living things. They can have
many different types of cells. Different types of cells look different
and have different jobs. For example, the cells in your skin look
different from the cells in your brain. The cells in your skin help
protect your body, and the cells in your brain help you think.
Cells of the same type group together to form tissues. You have
different tissues in different parts of your body. Like the rooms in
your school, each tissue has a special use. For example, in your
body, special muscle cells group together to form heart tissue.
Heart tissue helps the heart pump blood around your body.
Although you have different types
of tissues in your body, they can
work together. Tissues that work
together to do a job are part of a
system. Complex living things have
many different systems.
Each system has a certain job.
The heart tissue in your body works
with tissues in the arteries, veins,
and blood. Together, these tissues
make up your circulatory system.
The circulatory system brings
blood to all parts of your body.
You are a complex living thing.
All your systems work together to
keep you alive.
Humans are complex, multicellular living things. Even
your blood is made up of many different types of cells.
Discovery Education Science
© 2007 Discovery Communications, LLC
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What Is a Tissue?
Not all multicellular living things are complex. Sponges are simple
multicellular animals that live in the ocean. They are made of only a
few different types of cells. Each type of cell forms a tissue within
the sponge. The cells in each tissue work together to do a job.
The tissues work together to keep the sponge alive and healthy.
A sponge is a simple multicellular living thing. Its tissues
work together to help it take in food and survive.
Discovery Education Science
© 2007 Discovery Communications, LLC
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