White pulp
| White pulp | |
|---|---|
 | |
| Transverse section of a portion of the spleen. (Lymphatic nodule labeled at center right.) | |
 | |
| Spleen | |
| Latin | noduli lymphoidei splenici |
| Gray's | subject #278 1285 |
| Artery | trabecular artery |
| Vein | trabecular vein |
| Precursor | mesoderm |
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 merely local expansions or hyperplasia of the adenoid tissue, of which the external coat of the smaller arteries of the spleen is formed.
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).[1]
See also
References
- ↑ Le, Tao (2011). First aid to usmle step 1 2011. p. 201.
External links
- BU Histology Learning System: 07703loa
- 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"
This article incorporates text from a public domain edition of Gray's Anatomy.
| |||||||||||||||||||||||||||||||||