<prompt> A 39-year-old neurosurgeon picks up a scalpel, which activates numerous sensory receptors in her hand. An increase in which of the following best describes the basis for transduction of the sensory stimuli into nerve impulses?Activation of G proteinDecreased ion permeabilityDecreased transmitter releaseIncreased ion permeability  <response>: Viually all mechanical stimuli cause an increase in ion permeability usually to sodium in mechanoreceptors. If the membrane potential of the mechanoreceptor reaches a critical threshold value, an action potential is initiated. The G-protein second messenger system is typically involved. Transmitter release does not occur at the level of the mechanoreceptor, but if a mechanoreceptor is activated, afferent nerve impulses do stimulate transmitter release at the nerve terminal in the central nervous system. 