Question

1.) While hanging a picture on the wall the hammer slips and you hit your thumb. You experience a great deal of pain.
A.) Using the general sensation tract, trace the sensory pathway from the appropriate receptor to the brain. Include the specific nerves.

B.) Now trace the motor pathway from the brain to the wrist extensors to move your thumb away from the hammer.

Answer 1

Ans a) The sensory pathway for pain involves a number of neurons and nerves through which the pain is transferred from thumb to brain and all the way back to give a pain response. The peripheral nerve ending in the thumb after sensing the injury in the finger sends the signal to the sensory neuron which sends the impulse to the spinal cord along the axon. The axons form synapse and send the signal to the brain in the hypothalamus region. The thalamus sends the information further to the sensory cortex and after interpreting the pain, it sends the signal back to thalamus via the motor cortex. The thalamus sends the signal back to the motor neurons in the finger which reacts or responds to the pain. The nocireceptors sends the pain signal via the primary afferent neurons via the dorsal root ganglion and into the dorsal horn further continuing the signal to hypothalamus.

Ans b) After the signal reaches the brain after the activated nociceptors carry them to the brain after being hit by the hammer, the thalamus relay the signal to the somatosensory cortex that send back the signal to finger. The A-delta fibers are responsible for carrying the pain signal and bring it back to the finger for sensation.