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Unit 19: Biology Part 2 Page 46 of 137
Blood – It’s Not Just for body stays at the right
Vampires temperature.
The whole point of the What is Blood, Anyway?
cardiovascular system is to get
blood to all the parts of the body. Let’s take a closer look at what
If there’s a whole system just for blood is made of. Blood is made of
that, blood must be pretty four things: plasma, platelets, red
important. In fact, blood does blood cells, and white blood cells.
several important jobs in our body. Let’s take a look at each one of
these parts individually.
Plasma
Plasma is the liquid part of blood.
Plasma is about 90% water, with
the other 10% made of dissolved
proteins, glucose, ions, hormones,
and gases. Blood is mostly
Figure 18 – Blood has many plasma, so since plasma is mostly
important jobs in our body. water, blood is mostly water. By
itself, plasma is a golden-brown
First, blood is the body’s delivery color.
system. You can think of it as both
the postal service (delivering
things you want) and the garbage
company (taking away the things
you don’t). It carries things you
need, including nutrients, oxygen,
and other important chemicals to
all the parts of your body. It also
takes away waste products, Figure 19 – Plasma is a golden-
including carbon dioxide, from all yellow color.
the parts of your body. Besides
being a delivery system, blood Red Blood Cells (or RBC’s for
helps keep our bodies warm. By short) are disc-shaped cells that
moving warm blood around, our carry oxygen. Every cubic milliliter
of blood (that’s about 1/1,000 the
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