Periarteriolar lymphoid sheaths (PALS) are characteristic of which splenic component?

Periarteriolar lymphoid sheaths (PALS) are characteristic of which splenic component?

• A. Red pulp
• B. White pulp
• C. Capsule
• D. Trabeculae

Answer: (B)

PALS are the T-cell rich zones that wrap around the central arteries in the spleen’s white pulp. This arrangement marks the immune portion of the organ, where T lymphocytes are positioned to encounter blood-borne antigens and coordinate adaptive responses. Surrounding these sheaths are B-cell–rich areas (lymphoid nodules) that support humoral responses, all within the white pulp. The red pulp, by contrast, is organized around cords and sinusoids for filtering blood and destroying senescent red blood cells, not for lymphoid sheaths. Capsule and trabeculae are structural supports, not lymphoid compartments.

PALS are the T-cell rich zones that wrap around the central arteries in the spleen’s white pulp. This arrangement marks the immune portion of the organ, where T lymphocytes are positioned to encounter blood-borne antigens and coordinate adaptive responses. Surrounding these sheaths are B-cell–rich areas (lymphoid nodules) that support humoral responses, all within the white pulp. The red pulp, by contrast, is organized around cords and sinusoids for filtering blood and destroying senescent red blood cells, not for lymphoid sheaths. Capsule and trabeculae are structural supports, not lymphoid compartments.