How do anthelmintics primarily exert their action on helminths?

Anthelmintics primarily exert their action on helminths by impairing motility or metabolic processes. This mechanism is crucial because helminths, which are parasitic worms, depend on their motor functions and metabolic activities for survival and reproduction within their hosts. By disrupting these processes, anthelmintics effectively incapacitate the parasites, preventing them from being able to move, feed, and reproduce.

Different classes of anthelmintics target various aspects of the worm's biology. For example, some may interfere with neurotransmission, leading to paralysis of the worm, while others may inhibit essential metabolic pathways, ultimately leading to the death of the helminth. This targeted approach allows for the effective elimination of parasitic infections without causing significant harm to the host's cells or functions.

In contrast, options that involve enhancing nervous system stimulation, promoting digestion, or increasing immune response do not directly relate to the primary mechanisms by which anthelmintics function. Thus, their roles in helminth treatment are not as critical in comparison to the impairment of motility or metabolic activities.