Pain Flashcards
What are 3 components of pain?
1-Sensory-descriminative2-Cognitive3-Emotional/affective
The physiological process by which information on actual/potential tissue damage is conveyed to the CNS is called?
Nociception
Specialized Ion channels on sensory nerve endings that respond to noxious stimuli are called?
Nociceptors
Pain resulting from activation of nociceptors as a result of actual or potential tissue damage and processing by the CNS is called?
Nociceptive Pain-Somatic/visceral/inflammatory
A pathophysiological process, resulting from abnormal sensory processing which does not signal actual or potential tissue damage, does not promote healing or repair and may be considered a disease is called?
Neuropathic/neurogenic pain
Pain associated with musculoskeleton system that is well defined is called?
Somatic
Pain associated with internal organs and associated tissues and is dull burning or poorly defined is called?
Visceral
The selective reduction of pain perception without affecting other sensory modalities is called?
Analgesia
The absence of any sensation due to suppression of CNS is called?
Anesthesia*Local and General
What are the 4 main steps of the nociceptive process?
TransductionTransmissionModulationPerception
What are the 4 types of ion channels that are on nerve endings?
1-Mechanical2-Chemical3-Thermal4-Polymodal
What compound found in spicy foods depletes substance P by activating the TRPV1 polymodal nociceptor?
Capsaicin*numbness following pain
Second messengers such as bradykinins are released from chemically activated nociceptor nerve endings and have what effect?
Further activate nociceptors by sensitizing them in a positive feedback
Increased perception of pain in response to a painful stimuli is called?
Hyperalgesia
Pain evoked by normally non painful stimuli is called?
Allodynia
What are two major candidates for sensitization of nerve endings?
1-Substance p (SP) (nerve endings)2-Prostaglandins (damaged cells)
What affect to PGs have on nerve endings?
Activate Na channels making the cell more excitable
Which protein is a constitutive in many tissues, generates PGs for regulation, is inhibited by classic NSAIDs and is the basis of some adverse effects of NSAIDs?
COX-1*Aspirin blocks both COx1 and 2 but is more effective on 1
GI cytoprotection, platelet aggregation, renal electrolyte homeostasis and blood flow, and some pain and fever are mediated by which protein?
COX-1
Which protein is induced by hormones, growth and inflammatory mediators?
COX-2*blocked by classic NSAIDs and selective Cox-2 inhibitors
Renal electrolyte homeostasis and blood flow, Cardiovascular protection, pain, fever and inflammation are all mediated by what?
COX-2
How do NSAIDs work?
Inhibiting the synthesis of prostaglandins that are involved in sensitizing the nociceptor nerve ending
Which nociceptors are normally activated by mechanical stimulation (i.e. distention) but may be referred to somatic sites as well?
Nociceptors in the Viscera
Which axons are the largest, myelinated, very fast and transmit touch, and proprioception?
A-beta axons
Which axons are small, myelinatad, fast conducting and are associated with mechanical thermal nociceptors, transmitting fast or first pain?
A-delta axons
Which axons are small, un-myelinated, slow conducting and are associated with polymodal nociceptors, transmitting slow or second pain?
C axons
The plexus of nerves in the tooth are called what?
Plexus of Raschkow or Sub-Odontoblastic plexus
Where do the nerves in the dentition come from?
-Sensory afferents of the trigeminal nerve-Sympathetics from superior cervical ganglion
What are the two types of nerve fibers in the tooth?
1-A-delta fibers (sharp localized pain when dentin is first exposed)2-C-fibers (dull diffuse pain)
Where do nociceptive fibers synapse with projection neurons?
Dorsal horn of the spinal chord*AB and Ad fibers synapse close together. mixing touch with pain
What are the two important neurotransmitters in pain?
1-Glutamate2-Substance P
After decussating, projection neurons ascend contra laterally in the spinothalamic tract to where?
Thalamus*Major somatosensory relay
Where does the trigeminal nucleus input to?
Thalamus*Then goes to somatosensory cortex 1 and 2 (sensory) and limbic (emotional)
When dorsal horn projection neurons become sensitized and hyper-respond to nociceptive input it is referred to as what?
Central sensitization*contributes to hyperalgesia and allodynia. Prostaglandins likely involved
What area is the major site of action of analgesic drugs, a secondary mechanism for NSAIDs and a major site for opioids?
Dorsal horn of spine
Inhibition of pain by touch is referred to as?
Gate Control*AB and Ad/C fibers converge
When visceral afferent nociceptors converge on the same pain-projection neurons as the afferents from somatic structures causing pain it is called?
Referred pain*ie. sinusitis and dental pain
What normally terminated nociceptive pain?
Healing
Enkephalins/endorphins along with 5HT and NE act where to help modulate pain?
Mesencephalic Periaqueductal Gray
What are the two types of enkephalins that are 5 amino acids long and stimulate u and d receptors?
1-Methionine2-Leucine
Which molecules are 91 amino acids long and stimulate u and d receptors?
B-endorphins
Which molecules are 17 amino acids long, stimulate k receptors are are not abused?
Dynorphins A and B*block pain but are not pleasant
What are 3 features of Neuropathic pain?
1-1 or multiple damaged peripheral nerves2-Continuous deep burning, aching and/or periodic shock3-Triggers initiate the pain
What two typical pain treatments do not work well for neuropathic pain?
1-NSAIDs2-Opioids (inconsistent)
What types of drugs help with neuropathic pain?
1-Antidepressants (Cymbalta)2-Anticonvulsants (Lyrica, gabapentin)3-Corticosteroids
What is an endogenous analgesia elicited by suggestion called?
Placebo*most likely causes release of endorphins
