Sensory Physiology

Question 1

what nervous system are sensory systems a part of

Answer 1

peripheral nervous system

Question 2

where do sensory systems communicate information to

Answer 2

central nervous system

Question 3

what are receptors categorized by

Answer 3

modality (type of stimulus to which they respond)

Question 4

chemoreceptors

Answer 4

sensitive to specific chemicals (smell, taste)

Question 5

magnetoreceptors

Answer 5

sensitive to magnetic fields (balance, touch, hearing)

Question 6

electroreceptors

Answer 6

sensitive to electric fields

Question 7

nociceptors

Answer 7

sensitive to noxious chemical, mechanical, and thermal stimuli

Question 8

noxious definition

Answer 8

could evoke tissue damage

Question 9

photoreceptors

Answer 9

sensitive to light (electromagentic radiation)

Question 10

thermoreceptors

Answer 10

sensitive to temperature (infrared radiation)

Question 11

mechanoreceptors

Answer 11

sensitive to mechanical energy

Question 12

exteroceptors

Answer 12

respond to stimuli outside of the body

Question 13

interoceptors

Answer 13

respond to stimuli inside the body

Question 14

transduction

Answer 14

conversion of stimuli into electrical signals

Question 15

what do both transduction mechanisms involve + result in

Answer 15

membrane proteins + receptor potential

Question 16

ionotrophic transduction

Answer 16

receptors are ion channels that open when stimulated

Question 17

metabotropic transduction

Answer 17

receptors are G-protein coupled receptors that open ion channels via 2nd messengers when stimulated

Question 18

two classifications of sensory receptor cells

Answer 18

primary afferent neurons and epithelial sensory cells

Question 19

what is included in sensory signals

Answer 19

modality, location, intensity, duration

Question 20

labelled lines principle

Answer 20

distinct units of the brain are specialized for processing distinct sensory modalities, so based on where the signal is coming from the brain knows what type of stimulus it is

Question 21

what is encoded in the origin of afferent neurons

Answer 21

modality and location of the stimulus

Question 22

how is stimulus intensity coded

Answer 22

changes in AP frequency (over limited dynamic range)

Question 23

small dynamic range

Answer 23

response is quickly saturated but has high sensitivity to stimulus changes

Question 24

large dynamic range

Answer 24

wider range of detected intensities, low sensitivity to small changes

Question 25

examples of log scale

Answer 25

quiet sound not detectable in loud room but is in quiet room

Question 26

tonic receptors

Answer 26

depolarize throughout whole stimulus and adapt slowly

Question 27

phasic receptor

Answer 27

depolarize at beginning and adapt rapidly, stop when stim plateaus and start again with a change

Question 28

what is "tuning something out"

Answer 28

our brains stop responding to a consistent stimuli to focus energy on other more important things

Question 29

what do dendrites do

Answer 29

project into the airway to pick up odorants

Question 30

how do olfactory receptors encode odors

Answer 30

odors comprised of multiple odorant molecules, each activates specific subset of odorant receptors that allows brain to identify the smell

Question 31

steps of olfactory system

Answer 31

1. odorant binds to receptor 2. olfactory receptor cells activated and send electric signals 3. signals relayed in glomeruli + transmitted to higher brain regions

Question 32

species differences in odor reception

Answer 32

function is the same, # of receptors changes to increase sensitivity

Question 33

how do reef fish see UV light

Answer 33

they have UV cones that are sensitive to UV wavelengths

Question 34

how is UV perception beneficial

Answer 34

allows for prey capture (constrast of planktonic targets) and communication between schools of reflective fish

Question 35

colour wavelengths

Answer 35

each colour has a unique wavelength, red - lowest blue/purple - highest

Question 36

what species is electroreception found

Answer 36

lampreys, cartilaginous fish (sharks), other fish species, some amphibians, and platypus

Question 37

how do electroreceptors work

Answer 37

current opens voltage-gated Ca channels, depol causes NT release and triggers AP in PAN

Question 38

what is the structure that allows for electroreception

Answer 38

ampullae of lorenzini

Question 39

describe shark experiment to determine electroreception

Answer 39

testing to determine how sharks locate prey, manipulate conditions to eliminate potential for sight/smell prey capture and see if they are still able to find prey source

Question 40

what do sharks detect in electroreception

Answer 40

active muscles of prey producing electric currents (heartbeat)

Question 41

how do ciliary photoreceptors work

Answer 41

turn light into hyperpol signal causing light stimulus to initiate hyperpolarization

Question 42

rod function

Answer 42

non colour vision in dim light

Question 43

cone function

Answer 43

colour vision in bright light

Question 44

what structural features do rods and cones have

Answer 44

single folded cilium, high surface area w lots of photopigments, lots of mitochondria

Question 45

what do photopigments contain

Answer 45

g-protein coupled receptor and chromophore

Question 46

dominant photopigment in animals

Answer 46

rhodopsin

Question 47

what part of electromagentic range can we detect

Answer 47

400-700 nm (1500 wavelengths)

Question 48

why is colour blindness more common in males

Answer 48

red/green opsin is on X chromosome

Question 49

why does colour reduce underwater

Answer 49

light is absorbed/scattered by water molecules so colours with lower energy wavelengths disappear quickly (red) while short wavelengths can penetrate deeper (blue/violet)

Question 50

what is ambient light

Answer 50

dim blue daylight and bioluminescence

Question 51

what is UV used for

Answer 51

hunting and communicating

Question 52

why is mint "cold" and chili "hot"

Answer 52

menthol and capsaicen (plant derived chemicals) activate both thermo and chemoreception for specific TRP channels

Question 53

pit organs

Answer 53

allow snakes to hunt w infrared vision using TRP channels

Question 54

what triggers infrared receptors in black pine beetles

Answer 54

infrared-induced vibration mechanically stressing the tip of nerve cell

Question 55

what can animals sense via magnetoreception

Answer 55

direction and dip angle

Question 56

why are mechanisms of magnetoreception unknown

Answer 56

magnetic fields pass freely through tissue so location/size/distribution of receptors is unknown

Question 57

what are cryptochromes

Answer 57

non-opsin pigments that regulate circadian rhythmns

Question 58

mechanoreceptors

Answer 58

sensory cells that detect touch, pressure, motion, position, and sound

Question 59

skin tactile receptors

Answer 59

isolated sensory cells, include free nerve endings or enclosed accessory structures