What is "Normal" Lymphatic system absorbs/carries things too big to go into the arteries/veins 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 come in all sizes from pea to lima bean. The are not usually easily felt.