77. What is the role of an effector in a negative feedback loop?
Answer: A
The effector causes alteration for returning the physiological value to normal.
Effectors play a crucial role in negative feedback loops by executing changes that help restore physiological values to their set points. When a deviation from the normal range is detected, effectors work to correct this imbalance.
A) The effector causes alteration for returning the physiological value to normal.
This option accurately describes the role of an effector in a negative feedback loop. Effectors are responsible for implementing the necessary adjustments in physiological processes to counteract deviations from the normal range, thus ensuring homeostasis.
B) The effector initiates the entire cascade of signals produced by the brain.
This option is incorrect because the effector does not initiate the feedback process; rather, it acts upon the signals that have already been generated in response to a deviation. The initial detection and signal generation are typically the roles of sensors or receptors, not effectors.
C) The effector compares the physiological value with that of a normal range.
This option is incorrect as well. The comparison of physiological values with normal ranges is typically performed by the control center, such as the brain, rather than the effector itself. Effectors act based on the commands they receive rather than making comparisons.
D) The effector is a sensory neuron that monitors physiological value.
This statement is incorrect because effectors are not sensory neurons. Sensory neurons detect changes and relay information to the control center, while effectors are the muscles or glands that carry out the response to restore balance.
Conclusion
The correct answer is A, as it directly reflects the fundamental role of effectors in negative feedback loops—restoring physiological values to their normal state. Options B, C, and D misrepresent the functions of effectors, mistakenly attributing roles that belong to sensors and control centers, thereby highlighting the importance of understanding the distinct functions within feedback mechanisms.