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Flashcards in Chapter 48 Deck (38)
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1
Q

What are some major characteristics of slow pain? What kind of fibers carry slow pain?

A
  • slow, burning, aching, throbbing, nauseous and chronic
  • carried by Type C fibers and typically onset over 1 second or more
2
Q

What are some characteristics of fast pain? What kind of fibers carry fast pain?

A

Fast pain has a quick onset of about 0.1 second.

  • sharp, pricking, acute, and electric
  • Carried by A-delta fibers
3
Q

Which of the two pains (fast and slow) are deeper and associated with tissue destrction?

A

Slow pain

4
Q

What are the three type of stimuli that elicit pain?

A
  • Chemical (slow)
  • Thermal (fast and slow)
  • Mechanical (fast and slow)
5
Q

What kind of receptors are pain receptors?

A

-free nerve endings

6
Q

Do pain receptors display adaptation? What is the chemical reasoning?

A
  • No
  • prostaglandins decrease the threshold for pain stimulus and cause HYPERALGESIA which keeps the person apprised of a tissue damaging stimulus
7
Q

What Ion concentration directly correlates to intensity of pain?

A

K+ ion concentration

8
Q

What enzyme concentration will correlate with pain intensity? Why?

A
  • Proteolytic enzymes
  • attack the nerve endings and make them more permeable to ions
9
Q

How does tissue ischemia cause pain?

A

-build up of lactic acid as well as bradykinin and poteolytic enzymes signal cell damage and elicit pain

10
Q

What determine how quickly pain due to ischemia appears?

A

-rate of metabolism of the tissue

11
Q

What two actions of a muscle in spasm cause pain?

A
  • direct stimulation of mechanosensitive pain receptors
  • compression of vessels leading to tissue ischemia
12
Q

What two kind of fibers bring pain into the spinal cord?

A
  • A delta fibers (fast sharp pain)
  • C fibers (slow chronic pain)
13
Q

What is the significance of this “dual innervation” of pain?

A

-The fast Adelta fibers alert the person to the pain quickly and then the C fibers come into play about a second of so later and then progressively get worse. The C fibers keep ther person aprised of the insult.

14
Q

Which tract (neospinothalamic or paleospinothalamic) carry mechanical and acute thermal pain?

A

-neospinothalamic

15
Q

Which neurotrasmitter is used in the neospinothalamic pathway in the transmission of mechanical and acute thermal pain through Adelta fibers?

A

-glutamate (excitatory)

16
Q

What type of pain and fiber is carried in the paleospinothalamic pathway?

A
  • Chemical chronic pain
  • slow type C fibers

*think Paleo=old and old people have chronic pain

17
Q

What type of neurotransmitter is used in the paleospinothalamic pathway?

A

-GLUTAMATE AND SUBSTANCE P

18
Q

Where in the dorsal horn do paleospinothalamic pathway type C fibers terminate? Where do they go after that?

A

–lamina II and III (substantia gelatinosa)

-Then they meet up with the fibers from the fast pain pathway and follow them.

19
Q

How is a cordotomy used to relieve chronic pain? Is is always successful? Why or why not?

A
  • The anterolateral quadrant of the thoracic spinal cord is cut to relieve chronic pain
  • Not always successful becuase other areas of the spinal cord then become sensitized to pain and sensation that they were not before
20
Q

Why is it so hard to sleep when one is in chronic severe pain?

A
  • Pain fibers innervate the reticular formation as well as the intralaminal nuclei of the thalamus and project onto the cerebral cortex
  • constitutes the main system of arousal in the human brain.
21
Q

Why is pain from the viscera referred to somatic dermatomes?

A
  • branches of visceral pain fibers synapse in the spinal cord on the same second order neurons that somatic pain fibers do
  • Pain from the viscera is conducted through some of the same nerves as somatic pain therefore the signals can become “confusing” to the cortex.
22
Q

What are common causes of visceral pain?

A
  • Ischemia
  • Chemical stimuli (leaking Gi juices)
  • Spasm of hollow viscus
  • Distention of hollow viscus
23
Q

Which viscera are very sensitive to pain?

A
  • bile ducts
  • bronchii
  • parietal pleura
24
Q

What is the difference between primary and secondary hyperalgesia?

A
  • Primary hyperalgesia is due to hypersensitivity of the pain receptors themselves (sunburn)
  • secondary hyperalgesia is due to facilitation of the sensory transmission (lesions in the thalamus or spinal cord)
25
Q

Patient presents with loss of all motor function on the left, loss of all pain temperature and touch sensation on the right and loss of discrimitive touch on the left following a knife fight and injury to the spinal cord at T4.

What kind of lesion is he most likely presenting with?

A
  • Brown-sequard (hemisection lesion)
  • Ipsilateral motor loss, ipsilateral dorsal column loss, contralateral ALS loss
26
Q

What does meningities present as?

A
  • worst headache EVER (head explosion)
  • referred over the entire head
27
Q

How does low CSF cause pain?

A
  • Loss of CSF decreases the brain boyancy
  • the weight of the brain causes distortion and stretching of the dura
28
Q

What causes migraines?

A

-abnormal vascular event that causes spasm of the vessels in the head and produces ischemia

29
Q

Why does alcohol cause a hangover?

A
  • Toxic to the meninges
  • dehydration
30
Q

What are some extracranial causes of headaches?

A
  • Muscle spasm (emotional tension)
  • Nasal and accessory structures (sinus pressure)
  • eye disorders (Ciliary spasm and extraocular muscle spasm)
31
Q

Where are cold and warmth receptors located?

A

-immediately under the skin in discrete spots

32
Q

What type of fibers are warmth fibers?

A

-Type C free nerve ending fibers

33
Q

What type of fibers are cold receptors?

A

-small A-delta

34
Q

How do the temperature fibers progress as temp warms?

A

-At extreme cold, only cold pain fibers are stimulated, then as warming occurs, reception progresses to the cold receptors. Then warmth receptors become active, and then as temp increases more, hot pain fibers are stimulated (along with cold pain).

35
Q

What track do temperature fibers take?

A

-the same as touch and pain.

36
Q

Which laminae do the thermal fibers synapse in the dorsal horn?

A

Synapse in the tract of lissaur in lamina I, II, and III

37
Q

How are thermal receptors activated?

A

-most likely by chemical stimulation of the nerve endings by chemicals relased due to temperature change.

38
Q

Do thermal signal summate depending on the amount of skin exposed?

A

Yes