Cite this page: Mansouri J. Anatomy, histology & grossing-spleen. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/spleennormalanatomy.html. Accessed April 26th, 2024.
Anatomy
- Largest lymphoid tissue of human body, accounting for 25% of total lymphocytes
- Lies between fundus of stomach and diaphragm
- Normally 150 g with thin capsule
- Pathophysiology:
- Filters foreign matter including old / damaged blood cells
- Participates in immune response to blood borne antigens
- Major repository of mononuclear phagocytic cells in red pulp, lymphoid cells in white pulp and platelets
- Produces new blood cells in infants / children or adults with severe anemia
- Gross description: malpighian (splenic) follicles of white pulp are identifiable
Histology
- Composed of red pulp (occupies 75% of splenic volume) and white pulp separated by marginal zone
- Red pulp:
- Filters old / damaged red blood cells
- Traversed by thin walled venous sinusoids lined by littoral cells, a type of endothelial cell which also stains with histiocytic markers and has a discontinuous wall, allowing passing of red blood cells between sinus and cords
- Sinuses are separated by splenic cords (cords of Billroth) containing a labyrinth of splenic macrophages, which filter red blood cells and ingest old (normal lifespan is 120 days), damaged (seen in hereditary spherocytosis, sickle cell anemia) or antibody coated red blood cells
- Also remove Heinz bodies or other red blood cell inclusions (peripheral blood has Howell-Jolly bodies if no functional spleen is present)
- White pulp:
- Forms sheaths of lymphoid cells around arteries (periarteriolar lymphatic sheath), composed of T cells and lymphoid follicles (B cells) with surrounding mantle zone (proliferating B cells) and outer marginal zone (memory B cells)
- Traps antigens for processing
- In young infants, immature marginal zone may contribute to increased susceptibility to bacterial infections or sudden infant death syndrome (Hum Pathol 2004;35:113)
- Blood flow:
- Arteries terminate in fine penicilliary arterioles surrounded by lymphocytes, then enter red pulp sinusoids, then to splenic veins
Grossing
- Fresh tissue preferable for special studies and flow cytometry
- Section specimen every 3 - 5 mm
- Obtain imprints after blotting with a towel to remove excess blood
- Blocks should be thin for adequate fixation, since fixative penetrates spleen slowly
- Describe apparent white pulp disorders (nodules), red pulp disorders (diffusely enlarged spleen without follicles or nodules) or other
Drawings
Images hosted on other servers:
Visceral surface
Transverse section highlighting veins
Transverse section highlighting arteries
Transverse section
