Senses and Perception 1

Question 1

neuron receptive field

Answer 1

defined by the distribution of the neurons receptors

size of field varies depending on location in the body

Question 2

what is the general rule about receptor field sizes

Answer 2

the further from the body core, the smaller the receptive field and the greater the overlap (e.g fingers have v small receptive fields)

Question 3

two point discrimination

Answer 3

ability to discern two separate mechanical stimuli
measure of receptive field size
small 2pd = small receptive field = large cortical representation

Question 4

how to mechanoreceptors sense a stimulus

Answer 4

by a physical deformation to their membrane e.g pressing skin
channels are tethered to membrane so deflection on membrane pulls channels open

Question 5

transduction of stimulus

Answer 5

stimulus - change in receptor permeability - influx of cations (+ve) - depolarisation - AP

Question 6

what are the two receptors for chemoreceptors

Answer 6

ionotropic (ligand-gated)

GPCR

Question 7

ionotropic chemoreceptors

Answer 7

open when applied chemical binds to receptor

Question 8

GPCR chemoreceptors

Answer 8

binding to receptor protein activates chain of events causing phosphoryation of G protein and opening of channel
may be slight delay as receptor at a distance from channel

Question 9

since all Action potentials are the same how is intensity coded

Answer 9

by the frequency of APs

Question 10

sensory homunculus

Answer 10

distorted body map in the cerebral cortex detailing what brain region corresponds to what area of the body