Periaeriolar lymphoid sheaths are seen in which organ:

Ans. B: SpleenIn the white pulp, the T-cells areas surround the central aeries, forming the periaeriolar sheath (PALS)White pulpThe white pulp consists of lymphatic tissue surrounding aeries and nodules also associated with aeries.The nodules can be distinguished because of the aeries (central aeries).The lymphatic tissue immediately surrounding the central aery is known as the periaerial lymphatic sheath (PALS) and is composed of T-lymphocytes.The more peripheral pa of the nodules is known as the peripheral white pulp (PWP) and consists of aggregates of B-lymphocytes.Red pulpThe red pulp is like a sponge composed of cords of cells (splenic cords) and splenic sinusoids (venous sinusoids).The splenic cords (Billroth cords) are composed of :- Reticular cells and fibers- Fixed and wandering macrophages- Lymphocytes- Plasma cells- Blood cells (erythrocytes, granulocytes) and pl