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.
The lymphatic system plays a prominent role in immune function, fatty acid absorption, and removal of interstitial fluid from tissues. List the roles of the lymphatic system. The lymphatic system is a linear network of lymphatic vessels and secondary lymphoid organs. It is the site of many immune system functions, but it also has its own functions.
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.