Physiology of Pain Flashcards
What is nociception?
Ability to feel pain, caused by stimulation of a nociceptor
What are the four processes of nociception?
- Transduction
- Transmission
- Modulation
- Perception
What is transduction?
Process of changing external stimuli into action potential
What is CIPA?
Congenital indifference to pain, with anhidrosis
How can chronic pain present?
Altered functions within the MS and visceral systems
Chronic pain is caused by what?
Overstimulation of peripheral nerve in a permanent alteration in the dorsal horns (facilitated segments)
Why does chronic pain gets worse?
Leads to more activation of nerves
Sharp or pricking pain is fast or slow?
Fast
Burning, aching, throbbing pain is fast or slow?
Slow
What temp does tissue damage occur?
113 F
Chemical pain can only elicit fast or slow pain?
Slow
What are the chemical mediators of pain? (4)
- Bradykinin
- 5HT
- Histamine
- K
How do bradykinins and other chemokines elicit pain?
Increase [K] and make nerves more permeable
True or false: prostaglandins cause pain
False–only enhances sensitivity of nerve endings
How do muscles spasms cause pain?
Stimulating mechano-sensitive pain receptors and compressing blood vessels, causing ischemia
What are pain receptors?
C fibers (free nerve endings)
True or false: pain receptors adapt very little and sometimes not at all
True
What are the fibers that transmit acute/fast pain?
A-delta
What is the fast pathway for pain?
Neospinothalamic pathway
What is the slow pathway for pain?
Paleospinothalamic
What is the neurotransmitter involved in the neospinothalamic pathway?
Glutamate
What is the neurotransmitter involved in the paleospinothalamic pathway?
substance P
True or false: viscera have sensory receptors for no other kind of sensation besides pain
True
What is the MOA Of referred pain?
Visceral pain synapse in the spinal cord on the same nerve endings that receive pain from the skin
What is the trifurcation that nerves undergo? What is the consequence of this?
Afferents go up, down, and at spinal level in the dorsal horn
Pain spreads to more than just the spinal level involved
How does the brain stop pain?
Sends signals down the dorsal horn of the spinal cord
What are the transmitter substances that block pain signals going up?
enkephalins and 5HT
Stimulation of what fibers from peripheral receptors can depress the transmission of pain signals?
A-beta
Where do opioids act in the body to prevent pain?
Brain
Dorsal horn
Where do NSAIDS act in the body to prevent pain?
Peripherally
True or false: in pts with chronic pain, there is no relationship between the damage the body has undergone and the level of their pain
True
Most deep tissues are not extensively supplied with pain endings, but can still cause pain. Why?
Widespread tissue damage causes a summation effect to cause the slow/chronic aching pain in those areas
Pain receptors cannot adapt to a stimuli like other nerves. What is the consequence of this?
Person is kept apprised of the tissue damage
Stimulation of what fibers in the periphery can depress the transmission of pain signals? What can you do to simulate these fibers?
A-beta
Rubbing skin
What is the medical model of pain? How accurate is this?
Degree of injury or disease correlates with the degrees of pain
Inaccurate
What is the biopsychosocial model of pain?
Model of pain that takes into account social/economic factors
True or false: patients who transition from acute to chronic pain undergo a psychological change
True
What are the physical signs that point toward psychological in patients with pain? (3)
- Overreaction
- Odd emotions
- Inappropriate response to physical exam
