The spleen is an internal organ that is located in the left upper quadrant of the abdomen just below the left lung. It lies between the 9th and the 11th rib. In humans it appears brownish in color and is approximately 11 centimeters (4.3 in) in length. A spleen can weigh up to 200 grams (7.1 oz). The spleen is part of the lymphatic system and is supplied with blood by the short gastric arteries and the splenic artery. Read on to learn about the functions of the spleen.
What is the function of the spleen?
The main function of the spleen is to filter blood and to remove abnormal cells, such as old, decaying red blood cells. Red blood cells have a life span of approximately 120 days. Once this time period has passed the blood cell will be broken down and recycled in the spleen. Abnormal blood cells (red and white) are also removed and recycled by the spleen ensuring that the body remains healthy. In this case the spleen acts as a filter as abnormal red blood cells do not have the flexibility required to pass through the spleen, resulting in them becoming trapped and broken down.
It also plays a part in producing antibodies and lymphocytes that are used to fight disease and infection within the body. As the blood passes through the spleen it is filtered for microorganisms. The presence of a foreign substance will prompt an immune response and the active lymphocytes within the spleen will attack and break down the harmful substance.
The spleen also stores lymphocytes and red blood cells. When blood pressure drops within the body the spleen can send extra blood into circulation to help regulate the blood pressure. This also makes it a very vulnerable organ and susceptible to trauma. When the spleen ruptures it can cause such significant blood loss that a person may experience hypertension (low blood pressure) and shock.
The spleen is also responsible for making red blood cells during fetal development. Between the 9th and 28th week the spleen produces red blood cells until the bone marrow is formed in the 28th week. The spleen can make red blood cells for a child and an adult if the bone marrow is no longer functioning.