Spleen
The spleen (splen, lien) is the largest lymphoid organ located in the left hypochondrium at the level of the IX–XI ribs. Weight - 150–200 g, dimensions - approximately 12x7x3 cm. **About 300 ml of blood per minute passes through the spleen.
Building
The spleen is covered with a capsule made of dense connective tissue, from which trabeculae (septa) extend into the organ. The parenchyma consists of two functional zones:
White pulp (20% of volume) - accumulations of lymphocytes around arterioles (periarteriolar lymphoid couplings and follicles). Here's what happens:
- Antigen recognition
- Activation of T- and B-lymphocytes
- Antibody production (IgM)
Red pulp (80% of volume) is a network of venous sinuses and reticular tissue. Functions:
- Blood filtration - macrophages remove old and damaged red blood cells
- Blood depot - can contain up to 300 ml of blood
- Hemoglobin utilization (iron returns to the bone marrow)
Functions
- Immune - the spleen produces antibodies and filters the blood from bacteria, especially encapsulated (pneumococcus, meningococcus, Haemophilus influenzae)
- Filtration of red blood cells - old red blood cells (over 120 days old) lose flexibility and get stuck in the narrow crevices of the sinuses, where they are absorbed by macrophages
- Hematopoietic - in the fetus, the spleen is the active organ of hematopoiesis. In an adult, this function can be restored in case of bone marrow diseases.
- Platelet depot - up to 30% of all platelets are stored in the spleen
Splenomegaly
An enlarged spleen can be caused by:
- Infections (mononucleosis, malaria, endocarditis)
- Liver diseases (portal hypertension with cirrhosis)
- Hematological diseases (leukemia, lymphoma)
- Autoimmune conditions
Splenectomy
Removal of the spleen is indicated for trauma (rupture) or certain blood diseases. Life without a spleen is possible, but the risk of severe infections increases (OPSI syndrome - overwhelming post-splenectomy infection). Therefore, after splenectomy, vaccination against pneumococcus, meningococcus and Haemophilus influenzae is mandatory.
The spleen is the only organ that carries out “quality control” of red blood cells. Without it, old and defective cells remain in the bloodstream longer.
The Humio](/) app provides an interactive 3D model of the spleen in the context of the abdominal organs - consider its location, vessels and connections with neighboring structures.