Immune System - Overview
What is the immune system?
The immune system protects your child's body from outside invaders. These include
germs such as bacteria, viruses, and fungi, and toxins (chemicals made by microbes).
The immune system is made up of different organs, cells, and proteins that work together.
There are 2 main parts of the immune system:
These 2 immune systems work together.
The innate immune system
This is your child's rapid response system. It is the first to respond when it finds
an invader. It is made up of the skin, the eye's cornea, and the mucous membrane that
lines the respiratory, gastrointestinal, and genitourinary tracts. These all create
physical barriers to help protect your child's body. They protect against harmful
germs, parasites (such as worms), or cells (such as cancer). The innate immune system
is inherited. It is active from the moment your child is born. When this system recognizes
an invader, it goes into action right away. The cells of this immune system surround
and cover the invader. The invader is killed inside the immune system cells (called
The acquired immune system
The acquired immune system, with help from the innate system, makes special proteins
(called antibodies) to protect your body from a specific invader. These antibodies
are developed by cells called B lymphocytes after the body has been exposed to the
invader. The antibodies stay in your child's body. It can take several days for antibodies
to form. But after the first exposure, the immune system will recognize the invader
and defend against it. The acquired immune system changes during your child's life.
Immunizations train your child's immune system to make antibodies to protect them
from harmful diseases.
The cells of both parts of the immune system are made in different organs of the body,
Adenoids. Two glands located at the back of the nasal passage.
Bone marrow. The soft, spongy tissue found in bone cavities.
Lymph nodes. Small organs shaped like beans, which are located all over the body and connect via
the lymphatic vessels.
Lymphatic vessels. A network of channels all over the body that carries lymphocytes to the lymphoid organs
Peyer patches. Lymphoid tissue in the small intestine.
Spleen. A fist-sized organ located in the belly (abdominal) cavity.
Thymus. Two lobes that join in front of the windpipe (trachea) behind the breastbone.
Tonsils. Two oval masses in the back of the throat.
How do antibiotics help fight infections?
Antibiotics can be used to help your child's immune system fight infections by bacteria.
But antibiotics don’t work for infections caused by viruses. Antibiotics were developed
to kill or disable certain bacteria. That means that an antibiotic that works for
a skin infection caused by a certain bacteria may not work to cure diarrhea caused
by a different bacteria. Using antibiotics for viral infections or using the wrong
antibiotic to treat a bacterial infection can help bacteria become resistant to the
antibiotic so it won't work as well in the future. It's important to take antibiotics
as prescribed and for the right amount of time. If antibiotics are stopped early,
the bacteria may develop a resistance to the antibiotics. Then the infection may come
back again and be harder to treat.
Most colds and acute bronchitis infections won't respond to antibiotics. You can help
decrease the spread of more aggressive bacteria by not asking your child’s healthcare
provider for antibiotics in these cases.
Online Medical Reviewers:
- Daphne Pierce-Smith RN MSN
- Deborah Pedersen MD
- Marianne Fraser MSN RN