Final answer:
Normal superficial lymph nodes, unlike retroperitoneal lymph nodes, may be felt as small, palpable, bean-shaped structures when swollen and are important for immune system function.
Step-by-step explanation:
Normal superficial lymph nodes may be identified as palpable, small, bean-shaped structures. They are typically found near the surface of the body and become more evident when they are enlarged, such as during an infection or other immune response. Unlike retroperitoneal lymph nodes that are typically not visible, superficial lymph nodes can sometimes be felt by touch when they are swollen due to the body's response to pathogens. These lymphatic structures are essential components of the immune system, housing B cells, T cells, and other immune cells that react to foreign substances.
Lymph nodes are located along the larger lymphatic vessels, playing a major role in the body's defense mechanisms by filtering lymph and housing lymphocytes that contribute to immune responses. While the other lymphoid tissues, like lymphoid nodules—which are found in areas such as the respiratory and digestive tracts—lack a surrounding fibrous capsule, lymph nodes have a more complex structure with a fibrous capsule that encloses the germinal centers and facilitates the flow of lymph through the efferent lymphatic vessels.