Pain Flashcards
Define nociceptive
nociceptive means sensitive to noxious stimuli
Define Noxious stimuli
stimuli that elicit tissue damage and activate nociceptors
Define Nociceptors
sensory receptors that detect signals from damaged tissue or the threat of damage and indirectly also respond to chemicals released from the damaged tissue.
Nociceptors are free (bare) nerve endings found in the skin, muscle, joints, bone and viscera.
Recently, it was found that nerve endings contain transient receptor potential (TRP) channels that sense and detect damage. They transduce a variety of noxious stimuli into receptor potentials, which in turn initiate action potential in the pain nerve fibers. This action potential is transmitted to the spinal cord and makes a synaptic connection in lamina I and/or II.
The cell bodies of nociceptors are mainly in the dorsal root and trigeminal ganglia. No nociceptors are found inside the CNS.
What are the four nociceptors
Skin Nociceptors. Skin nociceptors may be divided into four categories based on function.
Joint Nociceptors. The joint capsules and ligaments contain high-threshold mechanoreceptors, polymodal nociceptors, and “silent” nociceptors.
Visceral organs contain mechanical pressure, temperature, chemical and silent nociceptors. The visceral nociceptors are scattered, with several millimeters between them, and in some organs, there are several centimeters between each nociceptor
Silent Nociceptors. In the skin and deep tissues there are additional nociceptors called “silent” or “sleep” nociceptors. These receptors are normally unresponsive to noxious mechanical stimulation, but become “awakened” (responsive) to mechanical stimulation during inflammation and after tissue injury.
Define transduction (1)
Neruotransmitter (Ex: prostaglandin) emiited from site of tissue damage. NSAIDs treat this type of pain.
What are the four steps in the nociceptor process?
Transduction, transmission, perception, modulation
Define transmission (2)
Electric pain impulse travels from peripheral nerves to the spinal cord, brain stem, thalamus, and the somatic sensory cortex. OPIODS inhibit the pain transmission process
Define perception (3)
The person becomes aware they they are pain.
Define modulation (4)
Person tries to stop cause of pain
Explain the gate control theory
Noceceptive pain travels to the spinal cord through small nerve fibers and Non-noceceptive pain travels through the spinal cord on big nerve fibers. When injury happens and the big nerve fibers are more active, you don’t feel much pain (heat packs, massages affect big nerve fibers). If the small nerve fibers are more active than the big nerve fibers then they block pain inhibiting neurons and cause extreme pain.
Acute pain triggers what part of the nervous system
Sympathetic nervous system (increased HR, BP, RR, bronchodilation, increased blood glucose, less gastric juice/urine output, less digesting)
Describes the effects of chronic pain.
Lasts 3 months or more.
Describe Nociceptive pain vs. Neuropathic pain
Nociceptive pain: Tissue damage to anything other than the nervous system
Neuropathic pain: Pain from damage to the nervous system causing abnormal sensory process input.
Difference between somatic and visceral pain
Somatic (musculoskeletal), Visceral (internal organ)
How is neuropathic pain often treated?
With anticonvulsants, antidepressants, and local anesthetic.
