mechanism

mechanism /mech·a·nism/ (mek´ah-nizm)

1. a machine or machine-like structure.

2. the manner of combination of parts, processes, etc., which subserve a common function.

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defense mechanism  a usually unconscious mental mechanism by which psychic tension is diminished, e.g., repression, rationalization, etc.

escape mechanism  in the heart, the mechanism of impulse initiation by lower centers in response to lack of impulse propagation by the sinoatrial node.

mental mechanism 

1. the organization of mental operations.

2. an unconscious and indirect manner of gratifying a repressed desire.

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mech·a·nism (mk-nzm)

n.

1. A machine or mechanical appliance.

2. The arrangement of connected parts in a machine.

3. A system of parts that operate or interact like those of a machine.

4. An instrument or a process by which something is done or comes into being.

5. The involuntary and consistent response of an organism to a given stimulus.

6. A usually unconscious mental and emotional pattern that dominates behavior in a given situation or environment.

7. The sequence of steps in a chemical reaction.

8. The philosophical doctrine that all natural phenomena are explicable by material causes and mechanical principles.

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mechanism,

n the path whereby a treatment works.

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mechanism,

n a structure of working parts functioning together to produce an effect.

mechanism, cough,

n a short inspiration, closure of the glottis, forcible expiratory effort, and then release of the glottis, with a rush of air at a flow rate of 3000 to 4000 cc/sec. It is essentially used or regarded as a process for removing foreign material from the lungs. It involves two phases. In the first, the combined action of the cilia and bronchiolar peristalsis moves the material up to the main bronchi and the bifurcation of the trachea. Further movement out of the respiratory system depends on the cough mechanism. In all medical conditions in which this mechanism is abolished or reduced, secretions and foreign material accumulate in the alveoli, with a resultant reduction in the aerating surface and a predisposition to infection. Because ventilation of the lungs depends on a patent airway, the cough mechanism should always be used by patients whose inadequate ventilation of lungs may be related to obstruction of the airway.

mechanism, inhibitory-excitatory

(inhib´itor´ē-eksī´ttor´ē),
n a mechanism that provides coordinated and continuous stimuli to the lower motor neuron for smooth, facile, and rapidly adjustable muscle contraction. This mechanism operates on every level of the central nervous system, from the final common pathway back up the spinal cord to the cerebrum. The excitatory phase of stimulation is transmitted directly to the nerve. Inhibition, however, is effected not by stimulating the motor output directly, as is done in the parasympathetic nerves, but rather by the interaction of inhibitory mechanisms on the excitatory impulses.

mechanism, respiratory control,

n the mechanism by which the respiratory functions are controlled. Three major factors in the control of respiration concern the clinician: neurogenic control of respiration, chemical regulation of respiration, and mechanical events leading to pulmonary ventilation. These three factors are significant in practice procedures because the clinician influences each of these factors in routine dental care; e.g., the patency of the airways is always subject to alteration by instrumentation, dental prostheses, and the use of pharmacologic agents, and the physically induced responses modify the rate and magnitude of the respiratory mechanism.

mechanism, self-cleansing,

n any of the structures within the oral cavity (e.g., teeth, saliva, oral mucosa, and tongue) that naturally allow the removal of substances entering the oral cavity that may affect the cleanliness of the cavity and promote the production of deposits.

mechanism, suspensory,

n the hammocklike arrangement of the structures comprising the attachment apparatus.

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mechanism

1. a machine or machine-like structure.

2. the manner of combination of parts, processes, etc., which subserve a common function.

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mechanism Medtalk The manner by which a process occurs; the arrangement or association of the elements or parts of a thing in relation to the effect generated