Scleritis (inflammation of sclera) is a strong indication of the underlying medical problem. It can be due to fungal, viral or parasitic infection, trauma, exposure to chemicals, poisonous gases or due to post-surgical complications.
Mast cells are granulated cells typically found in connective tissue. These cells mediate immune responses to foreign particles. In particular, they release large amounts of histamine and enzymes in response to antigen recognition.
One of the principle stimuli for secretion of acid by parietal cells is histamine, secreted from neighboring enterochromaffin cells. The histamine receptor on parietal cells is the H2 type, and blocking the binding of histamine to this receptor is a widely used method for suppressing gastric acid secretion.