My mother never calls me in the middle of a workday and, to tell the truth, I had no idea she even knew how to send a text. But when I felt the vibration in my pocket yesterday afternoon and pulled out my cellphone, there it was, a text message from Mom: “What is happening to our world?”

That’s the question on a lot of minds today, isn’t it? An act of terror here at home, at an iconic American event? No way. Not even possible.

Americans, so divided on so many issues these past several years — with a federal government nearly paralyzed by puffed-up partisanship — now suddenly united in our emotions. Horror. Sorrow. Outrage. But mostly disbelief. Did this really happen here? In our United States?

Even after Oklahoma City and 9/11, we are still capable of being shocked by such acts of cruelty and violence. In a globe rife with terror, where virtually every day brings news of explosions in public places that maim and kill dozens or even hundreds of people at a time, we are able to be surprised and sickened when such things happen on our shores to our fellow Americans.

If we can find comfort in anything at times like these, it may be in the ones who step up, who do what they are trained to do, what they have dedicated their lives to: the police, the firefighters, the paramedics, the health care professionals. Some of the TV coverage I watched last night showed bombing victims — many of them horrifically injured — being rushed into various Boston hospitals. As chaos reigned outside, inside those hospitals, clinicians and nonclinicians alike went about their jobs with the same steady urgency they exhibit every day, with every patient.

After 9/11, H&HN produced a poster depicting health care professionals — physicians, nurses, EMTs, hospital administrators and others — rising to the challenge of caring for so many victims. We called them “Defenders of the Home Front.” I think of that every time any kind of disaster hits a community in this country, whether it be man-made violence or a natural disaster. In every case, I’m reassured by the images of health care workers utterly focused on caring for those who need care.

I’m not sure how to answer my mother’s question. What is happening to our world? More tragedies like that in Boston are inevitable, I suppose. And as awful as that is to contemplate, at least it is comforting to know that America’s health care professionals will be there when we need them.