🔑 Key Definitions
Nociceptors: Specialized pain receptors that detect harmful stimuli
A-delta Fibers: Fast, myelinated fibers carrying sharp, localized pain
C Fibers: Slow, unmyelinated fibers carrying dull, aching pain
Endorphins: Body's natural painkillers (endogenous opioids)
A-delta Fibers: Fast, myelinated fibers carrying sharp, localized pain
C Fibers: Slow, unmyelinated fibers carrying dull, aching pain
Endorphins: Body's natural painkillers (endogenous opioids)
👤 Important Figures
- Melzack & Wall - Developed the Gate Control Theory of Pain
🧠 Gate Control Theory
- Key Concept: A "gate" in the spinal cord modulates pain signals
- Gate OPENS: Pain signals pass through to brain
- Gate CLOSES: Pain signals blocked or reduced
- Factors that CLOSE gate: Rubbing injury, positive emotions, distraction
- Factors that OPEN gate: Anxiety, depression, focus on pain
📊 Pain Pathway
- Step 1: Nociceptors detect harmful stimulus
- Step 2: Signal travels via A-delta or C fibers
- Step 3: Signal reaches spinal cord (substantia gelatinosa)
- Step 4: Signal modulated by "gate"
- Step 5: Signal reaches brain (thalamus → cortex)
💡 Exam Tips
- A-delta = FAST, sharp pain; C fibers = SLOW, dull pain
- Melzack & Wall = Gate Control Theory (memorize this pairing!)
- Rubbing an injury works because it CLOSES the gate
- Endorphins = ENDogenous mORPHINES (body's own opioids)
- Psychological factors (anxiety, attention) can OPEN or CLOSE the gate