sensory transduction

Question 1

what is a graded potential

Answer 1

Get cell to threshold so it can fire action potentials

Question 2

a beta fibres

Answer 2

large myelinated- touch, pressure, vibration

Question 3

a delta fibres

Answer 3

small myelinated- cold, fast pain and pressure

Question 4

c fibres

Answer 4

unmyelinated- slow pain and warmth

Question 5

what fibres is propioception stimulated by

Answer 5

A alpha and A beta

Question 6

mechanoreceptors

Answer 6

project up through ipsilateral dorsal columns
synapse in cuneate and gracile nuclei
2nd order fibres corss over midline in brainstem and project to reticular formation

Question 7

where do thermorecceptors and nociceptors synapse

Answer 7

dorsal horn
2nd order fibres cross over at midline
project up through lateral spinothalamic tract

Question 8

how do NSAIDS work

Answer 8

prostaglandin sensitise nociceptors to bradykinin
inhibit cyclo-oxygenase which converts arachidonic acid to postaglandins

Question 9

how do local anesthetics work

Answer 9

block sodium action potential and therefrom all axonal transmission

Question 10

how do opiates work

Answer 10

reduces sensitivity to nociceptors and block transmitter release in the dorsal horn
activate descending inhibitory pathways

Question 11

gate control theory

Answer 11

nociceptor fibres come into the dorsal horn and immediately synapse onto 2nd order neurons. decussate and project up thalamus in the lateral spinothalamic tract