In details, outline the protective role of the normal commensal microflora at mucosal surfaces

A patient came to a dental clinic with complaints of dry mouth and multiple dental caries lesions. In the course of collecting anamnesis, it was found that an allergic patient takes antihistamines that block the H2 histamine receptors of smooth muscle cells of the salivary glands. It is known that histamine is a mediator that stimulates the secretion of saliva. Explain the mechanism of action of these drugs if it is known that the next day after discontinuation of the drug, the patient's dryness disappeared. For this: а) write the classification of inhibitors according to the mechanism of action b) indicate what type of inhibitors the drugs are taken by the patient; confirm your conclusion in writing c) guess what structure this drug may have d) give a picture illustrating the action of this type of inhibitors.

What cell does hepatitis B damage? What causes hepatitis B? What are the treatment?

Why is it important to treat strep throat within the first nine days or so? What is the mechanism for damage beyond the throat area (rare, serious complications) if left untreated?