antihistamine. Antihistaminic Pharmacology An agent that counteracts the effects of histamine released during allergic reactions by blocking histamineâH 1 receptors Adverse effects Dry mouth, drowsiness, urine retention in â, tachycardia.hile the term antihistamine can broadly include any agent that blocks any histamine receptor, in practice it is usually used to denote those blocking the H 1 type of receptors (H1 receptor antagonists), those involved in allergic reactions.
While all of these Military service branches are uniformed, have. weapons, ranks and other such details that are. similar, the specific missions and focus of. each service is quite different. The US Army is charged as the primary land. combat force.
Types of Service. 1  The Military is comprised of 12 branches: five Active Duty and seven part-time duty. 2  Active-duty service members are full-time members of the Military. 3  They are employed either domestically or overseas.o problem. In this section, you'll find a brief overview of each Service branch, the differences between full-time and part-time duty and links to complete information on each Service. 1  Overview. 2  Army. 3  Marine Corps. 4  Air Force. 5  Coast Guard.