Attn outside of the context of a letter is simply slang for the word attention.. The abbreviation is often used in non-professional internet communications or works of literature that purposefully subvert traditional grammar.
As a result, lymphatic fluid may accumulate in the skin, producing swelling that can be uncomfortable or, in some cases, debilitating. The main function of the lymph nodes is filtering the lymphatic fluid, thus trapping viruses, bacteria and other foreign materials that could be found in lymph fluids.
Lymph nodes, lymph, and lymphatic vessels comprise the lymphatic system of the body. Lymph nodes filter lymph, a clear, sticky fluid that bathes body cells and collects waste products and debris.