Capsule of lymph node

The capsule of lymph node is a fibrous structure that encases the lymph node, providing structural support and protection. It is composed primarily of dense connective tissue, which includes collagen fibers and, in some species, smooth muscle cells.[1-2] The capsule plays a crucial role in maintaining the integrity of the lymph node and facilitating the flow of lymph through the node.

The capsule is also involved in the formation of the subcapsular sinus, a space beneath the capsule where lymph first enters the lymph node from afferent lymphatic vessels. This area is important for the initial immune response, as it contains subcapsular sinus macrophages that capture and present antigens to B cells