BMS11004 LABS

Question 1

what is a CAP

Answer 1

compound action potential, graded, summation of many all-ornothin AP

Question 2

name clinical application for CAP

Answer 2

measuring CAp allows studying peripheral nerve lesions or disease, measure nerve conduction velocity noninvasively

Question 3

what is shape of CAP

Answer 3

biphasic- wave of depolarisation travels along nerve and external electrodes record change in polarity of wave as passes underneath

Question 4

what is a CAP amplitude

Answer 4

2-4mV

Question 5

why is CAP amplitude reading smaller than for AP

Answer 5

AP requires measuring change in voltage across membrane using electrode directly inside the cell, so has higher signal strength/quality

Question 6

define visual acuity

Answer 6

capacity of eye for perceiving objects clearly, is expressed as “angle object must subtend at eye in order to be distinguished as separate entity”

Question 7

name 2 tests for visual acuity

Answer 7

Snellens types, landolts broken circles

Question 8

what does ishihara test

Answer 8

red/green colour blindness

Question 9

why is amplitude from EOG greater in light than dark

Answer 9

PD between retinal pigment epithelium is less in dark so deviation recorded by EOGs when eye moves depends on angle through which eye moves and intensity of eye illumination, adaptations to the light

Question 10

define optokinetic nystagmus

Answer 10

slow eye movement in direction of moving image followed by fast return to eye position in opposite direction