Question

A frog has its brain crushed, but when pinched on the leg, the leg draws away. It is an example of

• A. neurotransmitter induced response
• B. simple reflex
• C. condition reflex
• D. automated motor response.

Answer 1

Answer: (B)

simple reflex

The action does not involve the brain and is an example of a simple reflex. When the leg of the frog is pinched, the stimulus is received by receptors on the skin that set up a sensory impulse. This impulse is carried to the spinal cord through the dorsal sensory root of a spinal nerve. The spinal cord then transforms the sensory impulse into a motor impulse. This impulse is then transmitted to the leg muscles. The muscles on receiving the impulse contract and the leg is withdrawn to avoid the stimulus. So, the correct option is 'simple reflex'.