6. Which of the following is not a necessary feature of a reflex action
a. It is mediated by the nervous system
b. It is involuntary
c. It serves a protective function
d. It is a rapid response to a stimulus
Reflex Action MCQ Solution: Identifying Non-Essential Features
The correct answer is d. It is a rapid response to a stimulus. While speed defines most reflexes, some exhibit longer latencies through multiple synapses, making rapidity non-essential.
Option Analysis
a. It is mediated by the nervous system
All reflex actions require neural pathways, including sensory neurons detecting stimuli, relay neurons in the spinal cord or brain stem, and motor neurons activating effectors like muscles. This forms the reflex arc, essential for transmission.
b. It is involuntary
Reflexes bypass conscious brain control, occurring automatically via spinal cord circuits for immediate execution without decision-making. Involuntary nature ensures survival responses like withdrawal from pain.
c. It serves a protective function
Reflexes evolved for defense, such as the withdrawal reflex preventing burns or the blink reflex shielding eyes, enhancing organism survival. Even subtle reflexes like startle contribute to self-preservation.
d. It is a rapid response to a stimulus
Most reflexes prioritize speed via short arcs, but long-latency reflexes involve multiple synapses for complex processing, like certain postural adjustments. Rapidity aids efficiency but is not universally required.
Reflex action represents a fundamental biological mechanism where organisms respond instantly to stimuli through predefined neural pathways. Understanding the necessary features of reflex action helps CSIR NET aspirants tackle MCQs on neural control and coordination effectively. This guide breaks down the core characteristics, explains why one feature stands apart, and provides exam-ready insights.
