The trabecular artery branches (lower left) to form a central artery. It is surrounded by a lymphocyte nodule. In the white pulp, you can identify the central artery (HA24, ca), which goes out of the plane of section but can be seen again at the top of the image (ca). The white pulp remains closely associated with the central artery along its length. When the central arteries leave the white pulp and enter the red pulp, they are then called red pulp arteries or penicillar arteries (pa).