7+ Year Member
- Mar 14, 2010
Ok thanks, but why bronchoconstriction as opposed to dilation? Is there a specific reason for this?Allergies trigger an unwarranted immune response. Take for instance a nut allergy, a random example. Upon exposure to some nut molecule, certain/specific naive B cells intercept this molecule as foreign and activate an army of mature Ab producing B cells (Plasma Cells). These B cells are then stimulated to produce a specific type of antibody (IgE), which bind to mast cells (contain histamine and heparin). At this point, nothing too serious happens.
It's upon secondary exposure to the allergen, that problems arise. The allergen binds to the IgE antibody causing mast cells to implode and release its contents. Histamine has specific receptors within various areas of the PNS and CNS that illicit different responses. Binding of histamine to one of these receptors (bronchial smooth muscle) is what ultimately causes bronchoconstriction, restricting air intake and making it difficult for the individual to breath.
Think about it. If something perceived to be harmful is entering your body (either eaten or inhaled), your body will enter fight mode to protect itself and prevent less of it from entering the body. Bronchodilation would only exacerbate the problem by allowing more of the allergen into the body.Ok thanks, but why bronchoconstriction as opposed to dilation? Is there a specific reason for this?
I kind of used that term loosely as in, our bodies trying to fight off some infection or foreign invader/attack. But as far as the "fight or flight" response, which is due to sympathetic ns, that would instead cause broncodilation so that we can escape from say a predator, allowing us to breath and inhale much needed O2. Totally different scenario. Nice catch!No offense, but by "fight mode", are you referring to the sympathetic response? If so, it actually causes bronchodilation. Bronchoconstriction is due to an activation of parasympathetic nervous system [https://en.wikipedia.org/wiki/Bronchoconstriction].
Logically, your reasoning makes sense, but I am just curios what biological mechanism is responsible for this response.