Sensory Physiology

Question 1

sensory receptors ____ different forms of sensation to nerve impulses that are conducted to the central nervous system

Answer 1

transduce

Question 2

proprioceptors are a type of

Answer 2

mechanoreceptor (sense changes in pressure)

Question 3

nociceptors

Answer 3

potential damage (chemical, too hot , too cold)

Question 4

chemoreceptors

Answer 4

smell and taste specific

Question 5

simple dendritic endings: free

Answer 5

pain, temp, smell

Question 6

encapsulated simple dendritic ending

Answer 6

pressure and touch

Question 7

complex sensory receptors

Answer 7

rods and cones, hair cells, and modified epithelial cells (taste)

Question 8

adequate/ normal stimulus

Answer 8

the type/ modality of stimulus that a receptor is most sensitive to

Question 9

regardless of how a sensory neuron is stimulated…

Answer 9

only one sensory modality will be perceived

Question 10

the stimulus intensity is proportional to

Answer 10

the frequency of action potentials

Question 11

true or false the anteriolateral pathway has better localization then the dorsal column pathway

Answer 11

false: dorsal column pathway has better localization (AL has poor localization)

Question 12

what type of receptive field is more discriminate?

Answer 12

smaller receptive field

Question 13

lateral inhibition

Answer 13

sharpens contrast, pathway closest to the stimulus inhibits neighbors by releasing GABA which inactivates the calcium channels which causes less neurotransmitter to be released

Question 14

tonic receptors

Answer 14

slowly adapting, produce constant rate of firing as long as stimulus is applied (pain)

Question 15

phasic receptors

Answer 15

rapidly adapting; burst of activity but quickly reduce firing rate if stimulus maintained (pacinian corpuscle- type of mechanoreceptor)

Question 16

what could be responsible for a receptor adapting to a stimulus

Answer 16

opening of K channels (hyperpolarizing)

Question 17

where is the second order neuron located for discriminate touch?

Answer 17

the medulla

Question 18

where do synapses happen in the dorsal column pathway

Answer 18

the medulla and the thalamus

Question 19

the dorsal column pathway is associated with

Answer 19

fine touch, proprioception, vibration

Question 20

the anterolateral pathway is associated with

Answer 20

pain, temp, course touch

Question 21

where does the anterolateral pathway cross vs the dorsal column pathway

Answer 21

anterolateral pathway crosses at the spinal cord and the dorsal column pathway crosses in the medulla

Question 22

specifically where do you find the synapses in the medulla for the dorsal column pathway

Answer 22

nucleus gracilis and nucleus cuneatus

Question 23

true or false: the dorsal column pathway is also a motor pathway

Answer 23

false: just sensory

Question 24

sensory unit

Answer 24

one afferent neuron and all its receptors

Question 25

receptive field

Answer 25

the part of the body which when stimulated activates that afferent neuron

Question 26

trigger zone of a sensory receptor

Answer 26

more Na channels -> AP

Question 27

in a sensory receptor, at the transduction site- do we normally have graded potentials or action potentials

Answer 27

graded potentials

Question 28

How do you code intensity of stimulus at the transduction zone?

Answer 28

increase duration and amplitude (graded potential)

Question 29

How do you code intensity of stimulus at the trigger zone?

Answer 29

increase frequency and time (AP)

Question 30

how is stimulus intensity coded?

Answer 30

change frequency and recruitment (overlapp of receptor fields)

Question 31

where would you expect to see lateral inhibition

Answer 31

places where synapses occur (thalamus, nucleus cuneatus, nucleaus gracilis, etc)

Question 32

what loss would result from cutting through the right side of the medial lemniscus

Answer 32

loss of fine touch in the left side

Question 33

Explain the different order neurons and where they synapse in the anterolateral system

Answer 33

the first order neurons synapse with second order neurons in the spinal cord and cross before ascending; the second order neurons synapse with the third order in the thalamus

Question 34

A delta pain fibers characteristics

Answer 34

myelinated axons, mostly mechanical specific, small receptive field, sharp/prickling sensation

Question 35

C fibers

Answer 35

small unmyelinated axons, slow conduction, large receptive field, burning/aching

Question 36

gate-control theory

Answer 36

non-noxious input suppresses pain

Question 37

neospinothalamic tract

Answer 37

responsible for immediate awareness of the exact location of the pianful stimulus

Question 38

what are the pain pathways

Answer 38

neospinothalamic, paleothalamic, archispinothalamic