The Spleen
The spleen is
one of the largest organs in the lymphatic system. It is a brown, flat and oval
shaped organ that filters and stores blood to protect the body from infections
and blood loss.
Location
The spleen is
located between the stomach and the diaphragm in the left hypochondriac region
of the abdominal body cavity, protected by the ribs. It is delivered oxygenated
blood by the splenic artery, which branches off from the aorta and the celiac
trunk. The splenic vein carries deoxygenated blood away.
Structure
The spongy
inner tissue of the spleen contains blood vessels and hollow sinuses to store
blood, which it can release into circulation when the body has been injured and
additional blood is needed. Platelets are also stored with the blood to help
form blood clots if needed and to prevent further blood loss.
Functions
Around the
vessels and sinuses are regions of red pulp and white pulp. The red pulp
regions contain reticular fibers that filter old blood cells from the blood
flowing through the spleen. The captured cells are digested and leftover iron
and hemoglobin are recycled. The zone between the red and white pulp acts as a
filter to capture pathogens in the blood and pass them on to the white pulp.
The white pulp, made of lymphatic tissue containing macrophages, T lymphocytes,
and B lymphocytes destroys pathogens in the blood and produce antibodies.
During certain infections the spleen may enlarge due to the increase in stored
white blood cells, captured pathogens and antibodies.
Importance
The spleen is
not a vital organ, meaning that its functions are useful, but not essential for
life. In its absence, red bone marrow, the liver and the lymph nodes can do the
same filtration and blood recycling functions of the spleen. Because it is not
one of the vital organs it is soft, spongy and vascular. This means that any
damaged caused to the spleen is usually treated by it’s entire removal.
Untreated damage to the spleen could result in internal hemorrhaging and
eventual death.
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