(redirected from Trigger mechanism)
Also found in: Dictionary, Thesaurus, Legal, Encyclopedia.


an event that stimulates initiation of a subsequent event or process.
flow trigger a trigger for initiating assisted ventilation, consisting of a mechanism for measuring the patient's inspiratory effort and starting of assisted ventilation when flow reaches a given level.
pressure trigger a trigger for initiating assisted ventilation, consisting of a mechanism for measuring pressure and starting assisted ventilation when pressure reaches a given level.
time trigger a trigger for initiating assisted ventilation, consisting of a mechanism that measures frequency of respirations and starts assisted ventilation when the respiratory frequency is at a given point.


Term describing a system in which a relatively small input turns on a relatively large output, the magnitude of which is unrelated to the magnitude of the input.


Etymology: D, trekker, that which pulls
a substance, object, or agent that initiates or stimulates an action.


Cell biology
An event resulting in a cascade of intracellular activities.

The decision part of a firearm, the pulling of which, even if the gun being held is not loaded, is a critical element in a crime and a virtually indisputable sign of culpability.

Health legislation
An “if-then” clause placed in legislation, such that if certain actions do not occur by a predetermined date, then a specific action is taken. Triggers can be “hard” or “soft”, depending on the severity of the needed corrective measures.
Managed care
Any event(s) that causes a contingency plan to be implemented—e.g., a critical supplier does not deliver a product in an appropriate timeframe.
A factor that initiates and aggravates a behaviour or response.
Pulmonary medicine
A factor that may exacerbate asthma; a stimulus which causes an increase in asthma symptoms and/or airflow limitation.
Vox populi
Any device or situation in which a minimal effort has a disproportionately great consequence.


Pulmonology A factor that may exacerbate asthma; a stimulus that causes an ↑ in asthma Sx and/or airflow limitation


A substance, insect, object, or agent that initiates or stimulates an action.

Patient discussion about trigger

Q. What is the ingredient in perfume or Cologne that will trigger an asthma attack? There is something in cologne/perfume that's not in body spray that triggers my asthma. I went out with a friend and he had on cologne and my asthma starting bothering me. Before going out my asthma hadn't bothered me in months because I stay away from things that may trigger an attack. This often happens with other things like bleach, ajax or any bad odor

A. Anything that irritates the nose and bronchi can cause an attack. No one really knows why...but it does. Cigarettes and pollution are common cause also.

Q. how can these trigger his episodes and what exactly has happened to him? My son is a bipolar patient. We took him to the doctor as his manic episode has started again. This episode was a high one as compared to his previous episodes. Previous episodes used to get triggered due to his work related stress. He keeps himself in routine which makes his life comfortable. Recently he went on a vacation with his colleagues. Once he was back I found his condition was worse and soon his episodes started again. His regular medicines were not of any help. So I took him to the doctor. His medicines were not changed except a new one was added. Doctor had told to reduce on any stress as much as possible. Strictly he has been told to reduce on anything which triggers stress like coffee, tea, high sugar intake, on cigarettes as well. How can these trigger his episodes and what exactly has happened to him?

A. Depending on the type of vacation he took it is possible that he drank a lot of alcohol which interfears with the effectivness of his medications. It is also probable that he did not keep the routine that he is on while on his vacation. If it was a tropical vacationhe could have spent mornings drinking coffee waking up from late nights. There are so many possibilities. Now that he is home he can begin his routine again, take his medications as perscribed and you will see that the episode passes. I hope that for you and your son the episode passes quickly and without too much damage.

Q. what is the difference between tender points and trigger points. I read somewhere in the net that there are two points called tender and trigger points which are one of the symptoms of fibromyalgia. Is that true? If so what is the difference between tender points and trigger points?

A. What you have read about tender and trigger points are true. A tender point hurts to the touch and causes some degree of pain in that area, while a trigger point may not necessarily be painful to the touch but causes a degree of pain to be felt in another area. Fibromyalgia patients typically have a number of tender points and, according to the American College of Rheumatology, the diagnostic criteria for fibromyalgia stipulates that an FMS sufferer should have pain upon palpation (i.e. touch) in eleven of the generally accepted eighteen tender points. A tender point is verified in a physical examination in which approximately nine pounds of pressure are applied by touch and the patient acknowledges that pain is felt.

More discussions about trigger
References in periodicals archive ?
A key feature of our trap was the absence of a trigger mechanism or treadle.
It breaks like glass, has virtually zero creep and offers a level of shot control unsurpassed by any other factory trigger mechanism that I have tried to date.
The trigger mechanism on this particular rifle has mechanical adjustments (although breaking the shellac-sealed screws to make adjustments voids the warranty and is officially discouraged by the company), but every adjustment I tried still left it with a very heavy seven-pound-plus "stack" at the moment of break-off--even at the closest adjustment possible before interfering with the manual safety function.
He told coroner Dr Kieran Geraghty that when criminals shorten a shotgun it can interfere with the trigger mechanism.
The spokesman added that the trigger mechanism on the water tank was powered by a 12 volt re-chargeable battery "because it is greener".
The BATF has classified the Glock as double-action-only in terms of its trigger mechanism, and as I've said in previous articles, I feel this is somewhat of a misnomer.
The trigger mechanism operates in selective double-action and single-action modes.
Det Sgt Cronick, who is based at Rumney CID, added: 'If there is a need to handle the handgun, it is essential that the barrel is used to avoid contact with the trigger mechanism.
The trigger mechanism for the outstanding instalments has not kicked in yet but we wish Chris a successful season," he added.
The Blaser action is short, shallow, with an unusually compact trigger mechanism and straight pull bolt action.
It seems at Cork, and several other tracks, the trigger mechanism is sited too far behind the traps with the result the traps open at best as the hare is level with them, and arguably behind them-instead of the correct 11 metres ahead of the boxes as required by British rules.