spleten

The spleen is a fist-sized organ located in the left upper quadrant of the abdomen, protected by the lower ribs and connected to surrounding structures by peritoneal reflections. It is encased in a fibrous capsule and contains two main functional components: white pulp and red pulp. The spleen’s primary roles are to filter blood, remove aged or damaged red blood cells, and participate in the immune response to blood-borne pathogens.

White pulp is lymphoid tissue organized around central arteries and serves adaptive immunity. It contains B and T lymphocytes that respond to antigens circulating in the bloodstream. Red pulp consists of splenic cords and sinusoids where phagocytes remove senescent erythrocytes and pathogens, recycle iron, and store platelets. The spleen also serves as a reservoir for blood and, during fetal life, can contribute to hematopoiesis when needed.

The spleen’s blood supply comes from the splenic artery, a branch of the celiac trunk, which enters the organ at the hilum and branches within. Blood is drained by the splenic vein, which joins the portal venous system. The organ is susceptible to blunt trauma and may harbor accessory splenic tissue in some individuals.

Clinically, splenomegaly occurs in infections, liver disease, and hematologic disorders. Traumatic injury can cause splenic rupture and internal bleeding. Splenectomy, the surgical removal of the spleen, reduces filtering and immune functions, increasing infection risk with encapsulated bacteria;因此 vaccines and, in some cases, prophylactic antibiotics are recommended. Diagnostic imaging such as ultrasound or CT helps evaluate size and structure, and specialized scans can assess splenic function.