Quick Facts
The paracortical region is any of the areas of the peripheral lymphoid organs populated by T lymphocytes, e.g., the periarteriolar lymphatic sheath in the spleen, the paracortex in lymph nodes, and the parafollicular areas of gut-associated lymphoid tissue (Dorland, 2011).
Structure/Morphology
The paracortical region (or paracortex) is a homogenous zone that contains T lymphocytes and interdigitating dendritic cells. Dendritic cells present processed antigens to the T-cells. When stimulated, the T-cells proliferate and enlarge, thus expanding the paracortical region greatly, but do not produce follicular structures such as those in the cortex. The matured T-cells are dispersed to peripheral sites (Willard-Mack, 2006).
Anatomical Relations
The paracortex is an ill-defined zone located between the cortex and the medulla.
Function
In the paracortex, T-cells proliferate and enlarge when exposed to antigens.
References
Dorland, W. (2011) Dorland's Illustrated Medical Dictionary. 32nd edn. Philadelphia, USA: Elsevier Saunders.
Willard-Mack, C. L. (2006) 'Normal structure, function, and histology of lymph nodes', Toxicologic Pathology, 5(34), pp. 409-424.
