Week 3: Ch. 4- Pain Flashcards
What is pain?
Unpleasant sensation - Discomfort caused by stimulation of pain receptors
Body defense mechanism - Warning of a problem
Complex mechanisms - Many not totally understood
Subjective scales - Developed to compare pain levels over time
What are some causes of pain?
- Inflammation
- Infection
- Ischemia and tissue necrosis
- Stretching of tissue
- Stretching of tendons, ligaments, joint capsule
- Chemicals
- Burns
- Muscle spasm
SOMATIC VERSUS VISCERAL PAIN
Somatic pain
* From skin (cutaneous)
* Bone muscle
* Conducted by sensory fibers
Visceral pain
* Originates in organs
* Conducted by sympathetic fibers
* May be acute or chronic
_______________ (pain receptors) are free sensory nerve endings
Nociceptors
Nociceptors may be stimulated by:
*Temperature - extremes
*Chemicals - acids, bradykinin, histamine, prostaglandin
*Physical means: pressure
Define pain threshold
- Level of stimulation required to elicit a pain response
- Usually does not vary among individuals
Define pain tolerance
- Ability to cope with pain
- Culturally related
- Varies among individuals
Describe pain fibers
- Afferent fibers
- Myelinated A delta fibers
-Transmit impulses very rapidly
-Acute pain
-Sudden, sharp, localized - Unmyelinated C fibers
-Transmit impulses slowly
-Chronic pain
-Diffuse, dull, burning, or aching sensation
Dermatome
- Area of skin innervated by a specific spinal nerve
- Somatosensory cortex → “mapped” - Corresponds to source of pain stimuli
Reflex response
- Involuntary muscle contraction away from pain source / to guard against movement
- Spinothalamic bundle in the spinal cord
Neospinothalamic tract VS Paleospinothalamic tract
- Neospinothalamic tract → fast impulses; acute pain
- Paleospinothalamic tract → slow impulses; chronic, dull pain
- Spinothalamic tracts connect with reticular formation of brain
Somatic sensory area in the cerebral cortex located in the _________ lobe
parietal
Describe Gate control theory
- Control systems, “gates” built into normal pain pathways
- Can modify pain stimuli conduction and transmission in the ________________________________________
- Gates open - Pain impulses transmitted from ______________ to brain
- Gates closed - Reduces or modifies the passage of _______________________
- Control systems, “gates” built into normal pain pathways
- Can modify pain stimuli conduction and transmission in the spinal cord and brain
- Gates open - Pain impulses transmitted from periphery to brain
- Gates closed - Reduces or modifies the passage of pain impulses
Describe pain control method of ice
Impulses from _________________________ close _______.
Impulses from temperature receptors close gates.
Describe pain control method of Transcutaneous electrical nerve stimulation (TENS)
Increases sensory stimulation at site, blocking pain transmission
Describe pain control method of Opiate-like chemicals (opioids)
- Secreted by interneurons of the CNS (endogenous)
- Block conduction of pain impulses to the CNS
- Resemble morphine - Enkephalins, dynorphins, beta-lipoproteins
How do infants respond to pain?
physiologically
* Examples: tachycardia, increased blood pressure, facial expressions
Describe signs & symptoms of pain
- Pallor and sweating
- High blood pressure, tachycardia
- Nausea, vomiting, fainting. dizziness - May occur with acute pain
- Anxiety and fear - Frequently evident in people with chest pain/trauma
- Clenched fists or rigid faces
- Restlessness or constant motion
- Guarding area to prevent stimulation of receptors
Describe referred pain
- Source may be difficult to determine
- Pain may be perceived at site distant from source
-Characteristic of visceral damage in the abdominal organs
-Heart attack or ischemia in the heart
Describe phantom pain
- Usually in adults
- More common if chronic pain occurred
- Can follow an amputation - Pain, itching, tingling
- Usually does not respond to common pain therapies
- May resolve within weeks - months
- not fully understood