PNS PT. 2

Question 1

what is an indicator of a simple receptor

Answer 1

if dendrites of neurons are sensory neurons

Question 2

describe simple receptors in three ways

Answer 2

most receptors; little specificity (respond to chemical, pressure, temp, trauma); not protected by accessory structures

Question 3

what is an indicator of a complex receptor

Answer 3

dendrites are not sensory neurons

Question 4

what an example of a complex receptor

Answer 4

photoreceptors

Question 5

describe complex receptors in three ways

Answer 5

found in sense organs; protected by accessory cells + connective tissue; specific

Question 6

what do encapsulate nerve endings sense

Answer 6

pressure

Question 7

name four examples of encapsulated nerve endings

Answer 7

meissner’s corpuscle, Krause’s end bulb, pacinian corpuscle, Ruffini’s corpuscle

Question 8

what do nonencapsluated nerve endings sense + whats an example

Answer 8

sense pain + temp. changes; example = Merkel’s discs

Question 9

what are the three brain levels that work to transmit information

Answer 9

receptor level (sensory neurons) -> circuit level (ascending pathways) -> perceptual level (neurons in cerebral cortex)

Question 10

where is the info transmission process located

Answer 10

somatosensory system

Question 11

describe info going from first to second to third

Answer 11

anything that depolarizes first order sensory receptor neuron, will go to circuit level (second order)
but will not allways go to the third level (bc the second decides if we send to the third)

Question 12

how does a sensation occur

Answer 12

stimulus must excite a receptor and an action potential must reach the cns

Question 13

what are the four requirements for a sensation to occur

Answer 13

stimulus must match receptor specificity
stimulus must fall within receptor’s receptive field (area it monitors)
receptor must convert stimulus to graded potential
graded potentials in the first order sensory neuron must reach threshold

Question 14

what are the two types of graded potentials

Answer 14

receptor potential (receptor is separate cell - most are special senses)
generator potential (receptor part of sensory neuron)

Question 15

describe the activity of ion channels at the receptor level (aka sensory receptors aka first level) - 5 steps (ending with at circuit level)

Answer 15

• info enters activation gate as it opens during depolarization
• input/info flows through upstroke
• during repolarization, inactivation gate closes because cell is refractory
• once membrane potential ends, both gates close awaiting another depolarization
• now input is at circuit level

Question 16

what are inotropic receptors

Answer 16

form an ion channel pore

Question 17

give three examples of inotropic receptors

Answer 17

mechanoreceptor, thermoreceptor, electroreceptor

Question 18

what are metabotropic sensory receptors

Answer 18

indirectly linked with ion channels on the plasma membrane of the cell through signal transduction mechanisms (aka some kind of second messenger is necessary, like a G-protein)

Question 19

what are examples of metabrotropic sensory receptors

Answer 19

chemoreceptor + photoreceptor

Question 20

describe the circuit/second level of somatosensory processing

Answer 20

deliver impulses to correct region of cerebral cortex for localization and perception of stimulus

Question 21

describe ascending sensory pathways at the circuit level

Answer 21

consist of chains of neurons; 1st order take info from receptor level to spinal cord; inputs synapse with second order neurons in brain which synapse with third order which transfer input to the cerebral cortex

Question 22

does some input go to spinal cord and never reach the brain

Answer 22

yes

Question 23

describe the percuptal/third level of somatosensory processing

Answer 23

intrepration in cerebral cortex by sensory fibers

Question 24

what do sensory fibers at neuronal circuits in cerebral cortex do

Answer 24

tell brain “who” and “where” info is coming from (aka action potential is just info and brain doesnt know how to interpret it yet)

Question 25

what are three examples of sensory fiber complexity

Answer 25

magnitude of stimulus, quality (sweet vs bitter), pattern (melody of music)

Question 26

name the six levels of perceptual complexity

Answer 26

percuptal detection, magnitude estimation, spatial discrimination, feature abtrasction, quality discrimination, pattern recognition

Question 27

describe perceputal detection

Answer 27

detected that stimulus occurred

Question 28

describe magnitude estimation

Answer 28

detect stimulus intensity (determined by frequency coding)

Question 29

describe spatial discrimination

Answer 29

identify site of pattern of stimuli (how far can two points be before considered as one?)

Question 30

describe feature abstraction

Answer 30

difference in properties; velvet v marble

Question 31

describe quality discrimination

Answer 31

differentiate subsodalities of a sensation (sweet vs biter)

Question 32

describe pattern recognition

Answer 32

take in scene and recognize patterns (dot paintings, melody)