Pathophysiology Chapter 6: Pain Vocabulary

A complete set of vocabulary flashcards covering pain pathophysiology, pathways, theories, neurochemicals, assessments, treatments, and clinical syndromes.

Nociceptors

Pain receptors that detect painful stimuli and send pain signals along nerve fibers.

A-delta fibers

Large, myelinated nerve fibers that carry rapid pain signals.

C fibers

Smaller, unmyelinated nerve fibers that transmit slow pain signals.

Spinothalamic tract

The primary ascending neural pathway in the spinal cord that carries pain signals to the brain.

Endogenous opioids

Natural analgesic neurochemicals produced by the body, including endorphins, enkephalins, and dynorphins, that bind to receptors on pain fibers to block pain signaling.

Simple reflex arc

A protective motor response mechanism that occurs without brain input, consisting of an afferent neuron, an interneuron, and an efferent neuron.

Corticospinal tract

The primary pathway responsible for carrying outgoing motor signals from the brain down the spinal cord.

Periaqueductal gray matter (PAG)

A midbrain structure that activates enkephalin-releasing neurons projecting to the nucleus raphe magnus to modulate pain.

Nucleus raphe magnus (NRM)

A brainstem area containing serotonin-releasing neurons that descend to the dorsal horn of the spinal cord to inhibit pain signals.

Sensitization

A phenomenon that exaggerates the excitement of pain nerve fibers and decreases pain inhibitory signals.

Dermatomes

Specific regions of the skin innervated by sensory fibers of a single spinal nerve.

Transduction

The first step in Gate Control Theory in which painful stimuli are converted into neuronal signals.

Transmission

The second step in Gate Control Theory involving the movement of neuronal pain signals along nerve fibers toward the brain.

Modulation

The third step in Gate Control Theory where interneurons in the dorsal horn influence and gate pain signals.

Perception

The final step in Gate Control Theory representing the conscious awareness and interpretation of pain in the brain.

Neuromatrix pain theory

A pain theory proposing that a neural network in the brain generates pain patterns independently of nociceptive input, explaining phantom limb pain.

Acute pain

Pain that lasts hours or days and resolves as injured tissue heals.

Chronic pain

Pain persisting beyond the expected healing duration that serves no biological or protective purpose and is often driven by persistent inflammation.

Neuropathic pain

Pain resulting from damage or dysfunction of nervous tissue, characterized by burning, tingling, or paresthesia.

Deep somatic pain

Dull, poorly localized pain originating from ligaments, tendons, bones, or muscles.

Visceral pain

Pain arising from deep internal organs.

Referred pain

Pain perceived at a location distant from the site of actual tissue pathology.

OLDCART

A mnemonic framework for clinical pain assessment standing for Onset, Location, Duration, Characteristics, Aggravating factors, Relieving factors, and Treatment.

Wong-Baker FACES Pain Rating Scale

A visual rating scale displaying facial expressions corresponding to pain intensity levels from 0 (No Hurt) to 10 (Hurts Worst).

WHO step analgesic ladder

A stepped guide for pain management progressing from nonopioids for mild pain (Step 1) to weak opioids (Step 2) and strong opioids (Step 3) for severe pain.

Morphine

A prototypical Schedule II opioid analgesic that provides analgesia, euphoria, and sedation, but carries risks of respiratory depression, constipation, and dependency.

Naloxone

An opioid antagonist used to reverse opioid overdose, which can rapidly precipitate withdrawal symptoms.

Buprenorphine

A Schedule III opioid medication utilized to help manage withdrawal and wean patients from opioid dependence.

Cyclooxygenase-1 (COX-1)

An enzymatic pathway involved in producing prostaglandins that protect gastric mucosa, maintain renal perfusion, and aid thrombus formation.

Cyclooxygenase-2 (COX-2)

An enzymatic pathway producing prostaglandins involved in pain, edema, fever, and inflammation, targeted selectively by celecoxib.

Cyclooxygenase pathway

The metabolic process in white blood cells where arachidonic acid is converted by COX-1 and COX-2 enzymes into prostaglandins.

Prostaglandins

Inflammatory neurochemical mediators synthesized via the cyclooxygenase pathway that enhance pain, edema, and inflammation.

Substance P

An excitatory neurochemical in the spinal cord that amplifies pain signals.

Sciatica

A form of spinal nerve radiculopathy caused by nerve impingement in the L4-S1 region, leading to pain radiating down the leg with numbness and tingling in the foot.

Cervical radiculopathy

Impingement of spinal nerve roots in the neck causing pain and numbness radiating into the hand and fingers.

Diabetic peripheral neuropathy

Nerve tissue breakdown resulting from chronic hyperglycemia, causing sensory loss and paresthesias in distal extremities.

Complex regional pain syndrome (CRPS)

A chronic progressive disorder associated with autonomic nervous system dysfunction, marked by severe pain, swelling, and skin discoloration in an affected limb.

Postherpetic neuralgia

Persistent neuropathic pain following reactivation of dormant varicella zoster virus along a spinal nerve dermatome.

Fibromyalgia

A chronic pain condition defined by widespread pain at 11 of 18 specific tender point sites, accompanied by fatigue and mood disturbances without joint inflammation.

Trigeminal neuralgia

A disorder of the trigeminal nerve causing severe, stabbing facial pain lasting seconds to minutes, triggered by light facial contact, eating, or sound.

Multimodal analgesia

The clinical practice of combining multiple pharmacological and nonpharmacological interventions with distinct mechanisms of action to enhance pain relief and reduce side effects.