Pain Flashcards
What is the definition of pain?
Pain is a sensory and emotional experience associated with actual or potential tissue damage.
What are the two ascending pathways to the brain for pain?
- Sensory-Discriminative pathway (Lateral thalamus → Somatosensory cortex)
- Affective-Motivational pathway (Medial thalamus → Anterior cingulate, Insula, Amygdala)
What is the role of nociceptors in the acute pain pathway?
Nociceptors are specialized afferent neurons that detect pain.
What is the sequence of the acute pain pathway?
- Nociceptors detect pain
- Pain signal travels through the spinal cord via dorsal root ganglion
- Somatosensory cortex identifies where the pain is
- Brain processes emotional and physical response
What substances are released during peripheral tissue activation?
- Bradykinins
- Prostaglandins
- Potassium
- Histamine
What are the two types of nerve fibers for pain transmission?
- Aδ fibers (Fast, Sharp pain, Myelinated)
- C fibers (Slow, Dull pain, Unmyelinated)
What does the Gate Control Theory of Pain propose?
Aβ fibers activate an inhibitory interneuron and “close the gate” in the dorsal horn of the spinal cord which reduces pain signals reaching the brain.
What is the pathway for descending pain modulation?
Periaqueductal Gray (PAG) → RVM → Dorsal Horn
What are endogenous opioids?
- β-Endorphins
- Enkephalins
- Dynorphins
What is the most important opioid receptor?
μ (Mu) receptor is the most important.
What effects does chronic pain have on the brain?
Chronic pain may lead to gray matter loss in the DLPFC, ACC, and insula.
What characterizes neuropathic pain?
Neuropathic pain arises from nerve injury, is less responsive to opioids, and is harder to treat.
What is the role of capsaicin in pain treatment?
Capsaicin activates TRPV1 receptors which reduce chronic pain.
How does TMS help in pain perception?
TMS activates the prefrontal cortex to reduce pain perception.
What is the role of antidepressants in pain treatment?
- Enhance descending pain inhibition
- Boost natural pain-blocking signals
What are the functions of NSAIDs and opioids?
They block pain signals chemically.
