Spleen: structure, functions & disorders
The spleen is a large, soft, spongy organ located in the upper left side of the abdomen, just below the diaphragm. It is a part of the lymphatic system and is involved in several important functions, including immune defense, blood storage, and blood filtration.
Structure of spleen
The spleen is a soft, spongy organ that is located in the upper left side of the abdomen, just below the diaphragm. It is roughly the size of a fist and weighs around 150 grams in adults, although its size and weight can vary depending on age and health status.
The spleen is composed of two main types of tissue: red pulp and white pulp. The red pulp makes up the majority of the spleen’s mass and is responsible for filtering the blood and removing old or damaged red blood cells. The white pulp, on the other hand, is involved in the immune system and produces and stores white blood cells.
The spleen is supplied with blood by the splenic artery and is drained by the splenic vein. The splenic artery branches into smaller arteries, which supply blood to the red pulp and white pulp. The splenic vein, in turn, collects blood from the spleen and returns it to the circulatory system.
The spleen is surrounded by a fibrous capsule, which is covered by a layer of connective tissue. This connective tissue is further divided into trabeculae, which divide the spleen into lobules. The blood vessels and lymphatic vessels that supply the spleen are also surrounded by connective tissue, which helps to support and protect them.
Overall, the structure of the spleen is well-suited to its important functions, which include immune defense, blood storage, and blood filtration.
- Immune defense: The spleen plays a key role in the body’s immune defense by producing and storing white blood cells, such as lymphocytes and macrophages. These cells help to protect the body against infections and other foreign invaders.
- Blood storage: The spleen acts as a reservoir for blood, particularly red blood cells and platelets. When the body needs more blood, the spleen can release stored blood cells into circulation.
- Blood filtration: The spleen filters the blood to remove old or damaged red blood cells, as well as other cellular debris and waste products. It also helps to break down hemoglobin, the molecule that carries oxygen in red blood cells, and recycle its components.
Disorders of the spleen
- Splenomegaly: Splenomegaly is a condition in which the spleen becomes enlarged, often due to an underlying medical condition such as a viral infection, liver disease, or cancer.
- Splenic rupture: A traumatic injury to the spleen can cause it to rupture, leading to severe bleeding and other complications.
- Sickle cell disease: Sickle cell disease is a genetic disorder that causes abnormal red blood cells, which can become trapped and destroyed in the spleen.
- Thrombocytopenia: Thrombocytopenia is a condition in which there are too few platelets in the blood, which can be caused by a variety of factors including autoimmune disorders, viral infections, and medications. The spleen can sometimes trap and destroy platelets, worsening the condition.
Treatment for spleen disorders may include medications, surgery, or other interventions depending on the underlying cause and severity of the condition. It is important to consult a medical professional if you experience symptoms of a spleen disorder, such as abdominal pain, fatigue, or anemia.
First Year Pharm D Subjects Syllabus, Notes, PDF Books, MCQ