Spleen

The spleen is an organ located in the upper left abdomen of the human body, near the stomach and pancreas. Despite its location near the digestive organs, the spleen is part of the body's lymphatic system, which filters toxins and waste out of the body as part of the larger immune system. The spleen removes the body's old and damaged red blood cells and stores white blood cells for the fighting of infections.

The spleen is susceptible to several diseases and injuries that may affect the organ's function or necessitate its surgical removal from the body. Liver diseases or blood cancers may enlarge a spleen, which can cause abdominal pain. A ruptured spleen, or one that has been injured from a blow to the body, can cause internal bleeding and is usually a life-threatening emergency. Ruptured spleens may be repaired, but removing the organ is often the safest treatment. People can live without a spleen, but they are more prone to contracting infectious diseases.

Background

The spleen is part of the human body's lymphatic system. This subsystem of the immune system filters toxins, foreign bodies, and other materials out of the body. It accomplishes this task by moving a fluid called lymph throughout the body through lymphatic vessels. Lymph contains the white blood cells that fight bodily infections. The lymph travels to hundreds of lymph nodes located in multiple locations in the body. Some of these nodes are close to the surface of the body, while others are near the lungs and heart.

The body derives lymph from plasma in blood. Most plasma deposits its nutrients in the body's cells and then returns to the main circulatory system. Plasma that does not return to the system is converted into lymph. Lymph nodes transport lymph from all parts of the body to the neck area. Along the way, the nodes filter the lymph to obtain waste materials that can be deposited from the body. Once the lymph reaches the neck, two veins located beneath the collarbones convey the lymph back into the body's circulatory system. Circulating plasma in the blood continues to form new lymph.

Along with the hundreds of lymph nodes in the body, several organs of the lymphatic system also perform specific tasks to defend the body against infection. The spleen regulates the amount of red blood cells in the body. It creates white blood cells called lymphocytes to attack foreign microbes. Meanwhile, the thymus, located above the heart, holds immature lymphocytes that eventually become T cells, white blood cells that contribute to the body's overall immune system. The tonsils are the third primary organs of the lymphatic system. Located in the back of the throat, tonsils are clusters of tissue that fight off infectious agents that enter the body through the mouth.

The lymphatic system overall is subject to contracting a variety of conditions. Lymph nodes swell when they are infected because of the buildup of foreign bacteria and the lymph fluid that attacks them there. Swollen lymph nodes that do not return to normal size can make people uncomfortable. Doctors usually treat swollen nodes with antibiotics.

Overview

The spleen is about 5 inches (12.7 centimeters) long and weighs 6 ounces (170 grams). It is a soft, spongy organ that appears purple due to the number of blood vessels running through it. The spleen is located just above the stomach, though it is unrelated to that organ and plays no part in the digestive system. The spleen receives blood from the heart through the splenic artery. The splenic vein transports blood from the spleen to the portal vein that empties into the liver.

The spleen is composed of two types of tissue that directly control the organ's function. The white pulp portion of the spleen produces lymphocytes. The lymphocytes then create protein antibodies that attack microbes that have invaded the body and could cause infection. The spleen's red pulp manages the organ's blood-filtering functions. The red pulp breaks down old or damaged red blood cells and other waste from the blood and removes them from the body. Furthermore, the spleen's red pulp holds different types of white blood cells calls phagocytes, which consume foreign bodies such as bacteria and viruses.

The spleen can develop a number of conditions that may prevent the organ from fully performing its functions. Some of these conditions arise from physical injury, while others are caused by disease. One such condition is an enlarged spleen. This can be caused by the infectious disease mononucleosis, liver disease such as cirrhosis, or a blood cancer such as leukemia. Enlarged spleens sometimes produce no symptoms, but symptoms may include left abdominal pain, easy bleeding, and a feeling of fullness. Doctors treat enlarged spleens by treating the ultimate cause of the enlargement.

The spleen can become lacerated or ruptured due to physical trauma sustained in incidents such as car accidents or sports injuries. A laceration is a minor break in the spleen's surface. A rupture is a larger break in the surface. Both injuries are potentially life-threatening. A spleen that has been broken in any way can drain blood into the abdomen. This internal bleeding usually leads to shock, a sudden loss of blood pressure that includes symptoms such as fast heart rate, fatigue, and dizziness.

Doctors assess damage to the spleen to determine the best treatment. Some lacerated spleens may heal on their own during hospital stays. Doctors can surgically repair lacerated or ruptured spleens. It may also be necessary to remove part or all of a damaged spleen to prevent further internal bleeding. The spleen is removed only when the damage it has sustained cannot be repaired. This includes cases of rupture and cancer of the spleen. Spleen removal is usually a minimally invasive procedure involving several small incisions in the abdomen and a small camera called a laparoscope. Surgeons use the camera to see the spleen inside the body and remove it.

People can live without a spleen because the liver and lymph nodes assume some of the infection-fighting functions of the removed organ. However, people without a spleen are more at risk of contracting contagious illnesses due to the reduced strength of their immune system. Doctors suggest that people without a spleen receive a variety of vaccines after having the organ removed. These include vaccines for pneumococcus, a bacterium that can cause pneumonia, and an annual flu vaccine.

Bibliography

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