intro to sensory systems

Question 1

what is exteroception?

Answer 1

preception of stimuli originating outside of the body (receptors are found at or near body surface)

Question 2

what is interoception?

Answer 2

perception of stimuli originating inside the body (receptors are found within the body)
eg hunger, cramps

Question 3

what is proprioception?

Answer 3

perception of body position and movement (receptors are found within muscles, tendons and joints)

Question 4

what are the 6 sensory systems?

Answer 4

visual
auditory
vestibular
olfactory
gustatory
somatosensory

Question 5

what makes something a special sense? which sense is not a special sense?

Answer 5

special if the receptors for it are localized to one place in the body

somatosensory is not special sense

Question 6

what are collaterals?

Answer 6

branches of axons - axons can have multiple targets

Question 7

what is the role of the thalamus in sensory systems?

Answer 7

almost all relay there - exception = olfactory

Question 8

what are the 5 categories of stimulus? what are the types of receptors for each?

Answer 8

1: photons; photoreceptor
2: specific molecules; chemoreceptor (taste, smell)
3: mechanical force; mechanoreceptor (touch, hearing, proprioception)
4: temperature; thermoreceptor
5: chemicals released by tissue damage; nociceptor (pain)

Question 9

what is the receptor potential?

Answer 9

local graded potential that is translated into an action potential

Question 10

how does activation of photoreceptors lead to altered membrane permeability?

Answer 10

absorption of photons by rods and cones in the retina - changes rhodopsin molecule which activates G protein

Question 11

how does activation of chemoreceptors lead to altered membrane permeability?

Answer 11

ion channels open when specific molecules bind to them, or to a second-messenger G-protein

Question 12

how does activation of mechanoreceptors lead to altered membrane permeability?

Answer 12

ion channels are linked to the cytoskeleton and open when mechanical force is applied

Question 13

how does activation of thermoreceptors lead to altered membrane permeability?

Answer 13

not completely clear - may involve channels in the transient receptor potential (TRP)7family

Question 14

how does activation of cociceptors lead to altered membrane permeability?

Answer 14

not completely clear

also likely due to receptors in TRP family

Question 15

how is the duration of a stimulus conveyed?

Answer 15

response of a receptor to a constantly applied stimulus diminishes with time
receptors adapt at different rates

Question 16

how is location of a stimulus conveyed?

Answer 16

receptive field