Pain ( Garner)

Question 1

What is nociception?

Answer 1

Nociception is the sensory process that provides the signals that trigger pain.

Question 2

where are nocicpetors found?

Answer 2

Nociceptors are found in the periphery as simple free nerve endings

Question 3

What substances does tissue damage and inflammation trigger the release of?

*these substances sensitise peripheral nociceptors and induce hyperalgesia.

Answer 3

1) prostaglandins
2) Bradykinin
3) Histamine

These substances sensitize peripheral nociceptors and induce hyperalgesia

Question 4

What type of free nerve endings allows the transduction of nociceptive stimuli?

Answer 4

Unmyelinated “C” fibres (polymodal nociceptors)
and
Thinly Myelinated “Ad” Fibres (thermal and mechanical nociceptors)

Question 5

TRUE or FALSE :

Conduction velocity is possitively correlated with axon diameter

Answer 5

TRUE:

as the axon diameter increases the conduction speed increases.

Question 6

TRUE or FALSE :

Thermal and mechanical nociceptors have A-delta fibres which are thin and have a conduction speed of 5-30?

Answer 6

TRUE :
The thermal and mechanical nociceptors have A-Delta fibres.

**the polymodal nociceptors have C fibres

Question 7

TRUE or FALSE:

Polymodal nocicptors have myelinated C fibres

Answer 7

FALSE:
Polymodal nociceptors have UNMYELINATED C fibres.
These have a slow conduction velocity and transmit dull ache / burning pain.

Question 8

What types of fibres transmit 1st pain (sharp / easily localised /short duration ) Vs. 2nd pain (dull ache / poorly localised / persistent)

Answer 8

1st pain:
-fast A-Delta fibres

2nd pain
-Slow C-unmyelinated fibres

Question 9

Once the afferent nociceptive fibres enter the dorsal horn they travel up and down a short distance within the ……

Answer 9

Zone of Lissauer

Question 10

What accounts for referred pain?

Answer 10

The nociceptive afferents from the interal organs and skin enter the spinal cord through common routes and target overlapping populations of spinal neurons.

This cross talk accounts for referred pain whereby the visceral pain is percieved as having a cutaneous source by the sufferer.

Question 11

Where is reffered pain of the oseophagus?

Answer 11

Chest wall

Question 12

Where is referred pain of the heart?

Answer 12

Chest and arms

Question 13

Where is referred pain of the bladder?

Answer 13

Perineum

Question 14

Where is referred pain of the ureter?

Answer 14

lowe abdomen and back

Question 15

Where is referred pain of the prostate?

Answer 15

Lower trunk and legs

Question 16

Where is the pain from appendicitis usually felt in the early stages?

Answer 16

Pain is referred to the abdominal wall around the navel

Question 17

Where is the pain from angina usually felt?

Answer 17

upper chest wall and left arm

Question 18

What excitatory neurotransmitter is released by the pain afferents?

Answer 18

Glutamate

Question 19

What is the outcome of a unilateral spinal cord injury?

What is this called?

Answer 19

• loss of touch, pressure, vibration and proprioception (dorsal column~) on same side as lesion.
• loss of pain / temp of opposited side of lesion.

This is called DISSOCIATED SENSORY LOSS.

Question 20

What causes DISSOCIATED SENSORY LOSS?

Answer 20

Unilateral spinal cord injury

(loss of dorsal column on same side (below) lesion and loss of spinothalamic on opposite side (below) lesion.

Question 21

What is Brown- Sequard syndrome?

Answer 21

Dissociated sensory loss caused by a unilateral lesion of the spinal cord.

(ie loss of dorsal column on same side of lesion and loss of spinothalamic on opposite side of lesion.)

Question 22

Describe the pathway of pain and temperature sensationr from the face and head?

Answer 22

1) Cell body lies in the trigeminal ganglion.
2) fibres descends in the spinal tract.
3) Then enters the caudal part of the spinal nucleus.
4) Synapse with 2’ fibre.
5) crosses midline
6) Ascends to VPM of thalamus via the trigeminothalamic tract.

Question 23

Who came up with the gate theory of pain.

Answer 23

Melzack and Wall (1965)