Final answer:
Auricular lymph nodes are situated near the ear and play a crucial role in filtering lymph fluid as part of the immune system. They are associated with external ear structures and are involved in the body's immune response to infections around that area.
Step-by-step explanation:
The lymph nodes near the ear are commonly referred to as the auricular lymph nodes. These nodes are an integral part of the immune system, acting as filters that remove debris and pathogens from the lymph fluid. They are associated with the external ear structures, including the auricle and the ear canal, which extends back to the tympanic membrane.
Lymph enters these nodes through the afferent lymphatic vessels and passes into the subcapsular sinus. This is where dendritic cells, macrophages, and reticular fibers start the filtration process. Inside the lymph node's cortex, lymphoid follicles with germinal centers contain rapidly dividing B cells, surrounded by a layer of T cells and accessory cells. As the lymph moves through the node, it reaches the medulla, which houses medullary cords filled with B cells and plasma cells, and finally exits the node through the efferent lymphatic vessels.
When an individual experiences ear infections or other head-related illnesses, these auricular lymph nodes can become enlarged and tender, which is often a sign of the body's immune response to infection.