L27 - pain prelecture

Question 1

four main classes of somatosensory receptors

Answer 1

• tactile
• proprioception
• thermal sensations
• nociceptive (painful) sensations

Question 2

tactile (innocuous) sensations

Answer 2

mediated by low threshold mechanoreceptors, Merkel, Ruffini, Meissner & Pacinian types

Question 3

proprioception

Answer 3

mediated by muscle (spindle) & joint (Golgi tendon) receptors, some inputs from cutaneous mechanoreceptors

Question 4

Thermal sensations

Answer 4

mediated by thermoreceptors localized to discrete zones that exhibit hot & cold sensitivity

Question 5

nociceptive (painful) sensations

Answer 5

mediated by mechanical, thermal & polymodal nociceptors

Question 6

morphology of meissner corpuscles

Answer 6

looping axonal terminals that inter-twine supporting cells

Question 7

morphology of Merkel’s cells

Answer 7

dome structure atop axon terminals

Question 8

morphology of Pacinian corpuscles

Answer 8

sensory axon surrounded by fluid filled capsule

Question 9

morphology of Ruffini endings

Answer 9

nerve terminals intertwined with collagen fibres

Question 10

morphology of nociceptors

Answer 10

free nerve endings which penetrate epithelial cells - no morphological specilaisation

Question 11

areas of high touch sensitivity

Answer 11

fingertips, face

Question 12

areas of low sensitivity

Answer 12

torso, limbs