Final answer:
Nociceptors, which can be either myelinated or unmyelinated, transmit pain sensations to the spinal cord using substance P and glutamate as neurotransmitters. Myelinated fibers conduct signals faster and are associated with acute pain while unmyelinated fibers are linked to chronic pain sensation.
Step-by-step explanation:
Nociceptors are the sensory receptors that specifically carry pain sensations from the site of injury or stress to the spinal cord. These receptors can be either myelinated or unmyelinated, with the former typically providing rapid response to painful stimuli (sharp, acute pain) and the latter more associated with chronic, throbbing pain. The neurotransmitters involved in transmitting these pain signals are substance P and glutamate. Myelinated nociceptors are often associated with the spinothalamic tract, which crosses the midline at the level of the spinal cord and is responsible for relaying pain and temperature sensation. Unmyelinated fibers may project to several brain structures including the thalamus, which plays a key role in processing sensory information. Additionally, effective analgesics such as capsaicin, used in products like Icy Hot™, function by binding to nociceptors and inhibiting the perception of pain.