Final answer:
The constant regions of IgE antibodies specifically bind to the Fc receptors on the surface of mast cells, which are central to the body's allergic response and anaphylaxis.
Step-by-step explanation:
The constant regions of IgE antibodies bind tightly to receptors on the surface of mast cells. These cells are involved in allergic reactions and are found throughout the body. IgE is known for its role in allergies and anaphylaxis. Upon first exposure to an allergen, IgE is synthesized by plasma cells, and its Fc regions strongly bind to Fc receptors on mast cells. If a person is allergic to a specific substance, such as peanuts, peanut-specific IgE would be bound to the mast cells. Upon re-exposure to the allergen, mast cells release histamines and other modulators that can cause symptoms ranging from mild allergies to severe reactions such as anaphylaxis.