Lecture 7 (Quiz 2) Flashcards
What part of the body doesn’t have pain receptors?
- Brain
What is unpleasant sensory and emotional experience associated with actual or potential tissue damage? What are the three elements of pain?
- Pain
- Sensory, cognitive, emotional/affective
What is the physiological process by which information on actual/potential tissue damage is conveyed to the CNS? What are specialized ion channels on sensory nerve endings that respond to noxious stimuli? What is pain resulting from activation of nociceptors as a result of actual or potential tissue damage and processing by the CNS? What is a pathophysiological process, resulting from abnormal sensory processing, does not signal actual or potential tissue damage, does not promote healing/repair, and may be considered a disease?
- Nociception (response to harm/pain)
- Nociceptors
- Nociceptive Pain
- Neurogenic / Neuropathic Pain
What is pain associated with musculo-skeletal system and skin, and is also well defined? What is pain associated with internal organs and associated tissues, and is a dull, burning and is poorly defined? What is a selective reduction of pain perception without affecting other sensory modalities? What is absence of any sensation due to suppression of CNS function?
- Somatic Pain
- Visceral Pain
- Analgesia (Pain medications)
- Anesthesia (General and Local Anesthesia)
There are four basic processes in Nociception signal transmission. What are they starting from the initial pain signal to the brain? At what point would a Local Anesthetic or other Anesthetic be the most effective?
- Transduction (Skin pain receptor)
- Transmission (From the receptor to the spinal chord, near the ganglia)
- Modulation (Spinal chord)
- Perception (Brain)
- Transmission section
What are the specific ion channels on free nerve endings that respond to the actual or potential tissue trauma? What are the 4 types of stimuli / transducers are measured by these nociceptors? What 2 types of receptors do these transducers stimulate? _______ in an ingredient that is commonly found in peppers and is what is used in pepper spray. This acts on what polymodal nociceptor? What does this polymodal nociceptor act on to deplete the mediators of pain and cause a numbing effect?
- Transduction Nociceptors
- Mechanical, Chemical, Thermal and Polymodal (a combination of the other 3 transducers)
- TRP (Transient Receptor Potential) and P (Prostaglandin, Purino, Pyrimidine) Receptor types.
- Capsaicin
- TRPV1 (Polymodal receptors)
- Substance P (mediator for TRPV1)
Nociceptors use chemical messengers to activate more nociceptors (positive feedback). What is released during the inflammation to cause this nociceptor to be triggered and pain to be felt at the spot of inflammation? What is released by these Nociceptors to continue the inflammation until adequate healing has occurred? Where do these signals propagate before going to the spinal cord? What is this increased sensitivity and response to stimuli in and near an injured area called?
- Bradykinin
- Substance P (mediator for TRPV1)
- Dorsal Root Ganglion
- Sensitization
Sensitization is the increased sensitivity/response to a stimuli near the injured area. What is the increased perception of pain in response to painful stimuli? What is pain evoked by normally non painful stimuli? What are the two major candidates for sensitization? How do Prostaglandins stimulate the excitation of Nociceptors?
- Hyperalgesia
- Allodynia
- Substance P (SP): From nerve endings, and Prostaglandins (PGs): From damaged cells.
- PGs get stimulated which activate specific Na+ channels and make nociceptors more excitable.
What are the two main generators for Prostaglandins? What differentiates COX-1 and COX-2? (Constitutive vs Inducible, inhibited by, causes/effects)
- COX-1 and COX-2
- COX-1: Constitutive (always on/there) in many tissues. Inhibited by NSAIDS (Aspirin), Effects: GI cytoprotection, Platelet aggregation, Renal electrolyte homeostasis, Renal blood flow maintenance. (Is also the basis of some adverse effects of NSAIDS such as bleeding and stomach irritation.) and Pain, Fever and Inflammation.
- COX-2: Partially Constitutive and partially Inducible. Inhibited by NSAIDS (Aspirin) and COX-2 inhibitors (Celebrex). Effects: Constitutive: Renal electrolyte homeostasis, Renal blood flow and Cardiovascular Protection. Inducible: Pain, Fever and Inflammation.
How do NSAIDS cause an Anti-Nociceptive (Nociception Antagonist) effect?
- NSAIDS inhibit the synthesis of Prostaglandins that are involved in sensitizing the nociceptor nerve ending.
Nociception transmission to the spinal cord occurs via 2 axons (Alpha-Delta, and C Axons). What makes these axons different? (Size, myelinated, type of pain)
- Alpha-Delta Axons: Small, myelinated, fast conducting “first” or “fast” pain, associated with Mechanical and Thermal nociceptors.
- C Axons: Small, unmyelinated, slow conducting “slow” or “second” pain, associated with Polymodal nociceptors.
What are the plexus of nerves associated with dental nociception in the tooth called? Where does this nerve receive its sensory and sympathetic sensation from?
- Plexus of Raschkow (Sub-Odontoblastic Plexus)
- Sensory: Trigeminal nerve, Sympathetic: Superior cervical ganglion.
Modulation or the initial synapse of the nociceptive fibers into the spinal cord occurs on which part of the spinal cord? At this step, what are the important pain neurotransmitters? As the neurons ascend up the spinal cord, they cross the midline (contralaterally) in the _________ tract. What acts as the major Somatosensory relay in the brain? What nucleus inputs into the Thalamus? Once the signal enters the thalamus is sent to the somatosensory cortex and into what area?
- Synapse with Projection neurons in the Dorsal Horn.
- Glutamate and Substance P.
- Spinothalamic tract
- Thalamus
- Trigeminal Nucleus
- Limbic
Where does Nociceptive input (either facilitory or inhibitory) occur and therefor also the best places for analgesic drugs?What is it when the dorsal horn projection neurons also become sensitized and hyper-responsive to nociceptive input which contributes to hyperalgesia and allodynia (touch input)? What are thought to be involved in this?
- Dorsal Horn of the spinal chord
- Central Sensitization
- Prostaglandins
What are the major sites of Opioids, NSAIDS and Analgesic drugs?
- The Dorsal Horn of the spinal cord and Periacqueductal Gray.
