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Unit 19: Biology Part 2 Page 84 of 137
pressure. If you eat healthy foods epidermis, is tough and
and exercise regularly, you will be waterproof. This makes it hard for
less likely to have high blood pathogens to get in.
pressure, regardless of your
genetics. It is not possible to
change your genetics, but you can
control your lifestyle choices.
Your Body’s First Line of
Defense
Up to this point, we’ve been talking
about a lot of things you can do to Figure 72 – The epidermis is
prevent disease. Eating healthy, thick and keeps out many
exercising, avoiding cigarette pathogens.
smoking, washing your hands, and
avoiding vectors are all great Some parts of your body, including
choices you can make. To go your mouth and nose, are not
along with these lifestyle choices, covered by skin. These areas,
your body has some built in called mucus membranes, are
defenses against disease that not tough like skin, making them
happen without you even having to possible places for pathogens to
think about it. enter.
Have you ever seen pictures of old Fortunately, mucus membranes
castles? You probably noticed the have some defenses against
moat around the castle, designed pathogens. Mucus is one defense.
to keep invaders away. Believe it It is a moist, sticky substance, and
or not, your body has its own many pathogens get stuck in it
version of a moat, keeping before they can do any damage.
invading pathogens away. Your
“moat” is your skin! Your skin is Many mucus membranes also have
your largest organ, and is a cilia. Cilia are small hairs that
physical barrier between your sweep your mucus and any
insides and the outside world. The pathogens they may have trapped
outer layer of skin, called the toward openings in your body, like
your nose and mouth. When you
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