Question

The crossed-extensor reflex is initiated by activation of what type of receptor?

A) muscle spindle stretch receptor
B) nociceptor
C) warm receptor
D) taste receptor
E) photoreceptor"

Answer 1

The crossed-extensor reflex is initiated by nociceptors, which are receptors that transduce painful stimuli and activate motor neurons to facilitate withdrawal from the stimulus.

Step-by-step explanation:

The crossed-extensor reflex is initiated by the activation of a type of somatosensory receptor known as a nociceptor. Unlike the reflexes mediated by muscle spindle receptors described by the stretch reflex, which are activated by the stretching of skeletal muscles, nociceptors are responsible for transducing painful stimuli.

In scenarios like stepping on a tack, nociceptors activate the motor neurons responsible for contracting the tibialis anterior muscle, facilitating withdrawal of the foot, while inhibiting antagonist muscles.