Transverse section of a portion of the spleen. (Lymphatic nodule labeled at center right.)
|Latin||noduli lymphoidei splenici|
||This article needs attention from an expert in Anatomy. (November 2008)|
White pulp is a histological region of the spleen. The altered coat of the arterioles, consisting of adenoid tissue, presents here and there thickenings of a spheroidal shape, the white pulp (Malpighian bodies of the spleen, splenic lymphoid nodules).
These bodies vary in size from about 0.25 mm. to 1 mm. in diameter.
They are most frequently found surrounding the arteriole, which thus seems to tunnel them, but occasionally they grow from one side of the vessel only, and present the appearance of a sessile bud growing from the arterial wall.
There are several parts of white pulp with distinct functions:
- Periarteriolar lymphoid sheaths (PALS) are typically associated with the arteriole supply of the spleen; contain T lymphocytes.
- Lymph follicles with dividing B lymphocytes are located between PALS and marginal zone. IgM and IgG2 are produced in this zone. These molecules play a role in opsonization of extracellular organisms, encapsulated bacteria in particular.
- Marginal zone is located further away from the central arteriole (in proximity to red pulp), it contains antigen presenting cells (APCs).
- Le, Tao (2011). First aid to usmle step 1 2011. p. 201.
- Histology image: 07703loa - Histology Learning System at Boston University
- White+pulp at eMedicine Dictionary
- Swiss embryology (from UL, UB, and UF) qblood/lymphat06
- Anatomy Atlases - Microscopic Anatomy, plate 09.174 - "Spleen: White Pulp splenic nodule"
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