Question 77

The effector causes alteration for returning the physiological value to normal.

Effectors play a crucial role in negative feedback loops by enacting changes that restore physiological values to their normal ranges. When deviations from the set point occur, effectors respond to correct these imbalances.

A) The effector causes alteration for returning the physiological value to normal.

This option is correct because effectors are responsible for carrying out the responses needed to bring the physiological value back to its set point. For example, in thermoregulation, effectors such as sweat glands or muscles work to decrease or increase body temperature, respectively, thus restoring homeostasis.

B) The effector initiates the entire cascade of signals produced by the brain.

This option is incorrect as the effector does not initiate the cascade of signals; rather, it acts upon signals already produced by the control center (such as the brain). The initiation of the feedback loop typically involves sensors and a control center that processes information before signaling the effector to act.

C) The effector compares the physiological value with that of a normal range.

This option is incorrect because the comparison of physiological values with the normal range is the function of the sensor or control center, not the effector. The effector's role is to act on the signals received, rather than to perform the comparison itself.

D) The effector is a sensory neuron that monitors physiological value.

This option is also incorrect. The effector is distinct from sensory neurons; while sensory neurons detect changes in physiological values, effectors are the components that execute the corrective actions based on the information provided by the sensors.

Conclusion

In summary, the correct answer, A, accurately describes the role of the effector in a negative feedback loop as it is the component responsible for making changes to restore normal physiological conditions. Options B, C, and D fail to capture the true function of effectors, as they either misattribute roles or confuse the processes involved in feedback regulation.