The spleen is located in the upper left part of the belly under the ribcage. It
helps protect the body by clearing worn-out red blood cells and other foreign bodies
(such as germs) from the bloodstream.
The spleen is part of the lymphatic system, which is an extensive
drainage network. The lymphatic (lim-FAT-ik) system works to keep body fluid levels
in balance and to defend the body against infections. It is made up of a network of
lymphatic vessels that carry
— a clear, watery fluid that contains proteins, salts, and other substances
— throughout the body.
What Does the Spleen Do?
The spleen acts as a filter. It weeds out old and damaged cells and helps control
the amount of blood and blood cells
that circulate in the body.
The spleen also helps get rid of germs. It contains white blood cells called
and macrophages. These cells work to attack and destroy germs and remove
them from the blood that passes through the spleen.
The body also uses the spleen as a place to store blood and iron
for future use.
What Does the Lymphatic System Do?
One of the lymphatic system's major jobs is to collect extra lymph fluid from body
tissues and return it to the blood. This is important because water, proteins, and
other substances are always leaking out of tiny blood capillaries into the surrounding
body tissues. If the lymphatic system didn't drain the excess fluid, the lymph fluid
would build up in the body's tissues, making them swell.
The lymphatic system is a network of very small tubes (or vessels) that drain lymph
fluid from all over the body. The major parts of the lymph tissue are located in the:
The heart, lungs, intestines, liver, and skin also contain lymphatic tissue.
The major lymphatic vessels are:
the thoracic duct: It begins near the lower part of the spine
and collects lymph from the pelvis, abdomen, and lower chest. The thoracic duct runs
up through the chest and empties into the blood through a large vein near the left
side of the neck.
the right lymphatic duct: It collects lymph from the right
side of the neck, chest, and arm, and empties into a large vein near the right side
of the neck.
The lymphatic system also helps defend the body against germs (viruses, bacteria,
and fungi) that can cause illnesses. Those germs are filtered out in the lymph nodes,
small clumps of tissue along the network of lymph vessels. Inside the lymph nodes,
lymphocytes called T-cells and B-cells help the body fight infection. B cells make
antibodies — special proteins that stop infections from spreading
by trapping disease-causing germs and destroying them.
Most of our lymph nodes are in clusters in the neck, armpit, and groin area. They're
also found along the lymphatic pathways in the chest, abdomen, and pelvis, where they
filter the blood.
When a person has an infection, germs collect in the lymph nodes. If the throat
is infected, for example, the lymph nodes in the neck may swell. That's why doctors
check for swollen lymph nodes (sometimes called swollen "glands") in the
neck when someone has a sore
throat. This is called lymphadenopathy.