Lec 3

Question 1

Pathway of Pain

Answer 1

-the first thing to be activated by a noxious stimulus is the peripheral nervous system
-all sensory info from sensory nerves in the body go to the spinal cord, at this stage it is nociception, not pain
-pain is a conscious thing, so nociception must got to the brain
-through input it goes to the brain
-the brain can modulate the input coming from the spinal cord

Question 2

Pain Relevant Loci

Answer 2

-skin/muscle/joint/visceral organs
-dorsal root ganglion
-dorsal horn of the spinal cord
-brain

Question 3

-dorsal horn of the spinal cord

Answer 3

-where the nerves enter the spinal cord
-goes in dorsal horn and not ventral bc sensory info is always dorsal and motor info is always ventral

Question 4

dorsal root ganglion

Answer 4

-near but outside the spinal cord
-what the peripheral nerves go through

Question 5

skin/muscle/joint/visceral organs

Answer 5

-all peripheral organs that are ennervated
-cant feel pain in thre brain bc there are no peripheral nerves

Question 6

Ascending Pathway

Answer 6

-not selective to pain
-tracts from the spinal cord
-thalamus
-somatosensory cortex
-bc pain is a sensation
-limbic cotex
-bc pain is an emotion
-prefrontal cortex
-bc pain affects learning and judgement

Question 7

Descending Pathways

Answer 7

-descending pathways exist bc sometimes the brain wants to ignore pain so it modulates the spinal cord so it stops sending those signals
-chronic pain comes from either too much ascending info or not enough descending info
-hypothalamus
-midbrain
-brainstem
-spinal cord

Question 8

Skin

Answer 8

2 types of skin, hairy skin and glabrous skin (palms of hand and soles of feet only)
-different nerves, and most of the time they have free nerve endings, they just starts in the skin

Question 9

Types of Nerve Endings

Answer 9

-merkles discs (light touch in hairy skin)
-ruffini terminals (stretch)
-Meisners corpsucle (light touch in globoulus skin)
-pacinian corpsuclues (vibration)
-free nerve endings sensitive to pain
-free nerve endings have small bulbs as the end

Question 10

Nociceptors

Answer 10

-are waiting to be stimulated be something noxious coming into contact with that particular part of the skin
-a nociceptor is a nerve fibre specialized to detect noxious stimuli
-nociceptors are unipolar neurons