It is common practice in Chinese medicine (in languages other than Chinese) to capitalize terms that either have no real translation (such as Qi), or that mean something different in Chinese medicine than they might mean in another system (such as the term Heart in western biomedicine). Similarity in term does no imply the same meaning, and Chinese physiology is based on a very different model than we are used to in the West. If an organ name is capitalized, it means the Chinese medical concept of that organ, not the one you may be more familiar with.