What is the difference between a gland and a lymph node?

Different functions: Glands secrete fluids like saliva or hormones (salivary, pituitary, etc.). Lymph nodes "taste" the lymph for anything bad like bacteria/viruses/cancers, etc. When it detects a problem, it alerts the immune system and your body reacts. They enlarge in response to the inflammation they create when they react. They shrink when all is well. They do not secrete anything.