GenPrinciples of Sensory Physio Flashcards
pressure and pain are submodalities of what modailty?
pressure and pain are submodalities of the SOMATOSENSORY modality.
modality is one of the stimulus attributes coded for by sensory system. other types of modalities include vision, audition, balance, taste, olfaction, and visceral sense.
attributes of a stimulus coded for by the sensory system include modality/quality (above), intensity, location, and duration of sensation.
what attributes of a stimulus (an incoming signal) are coded for by the sensory (afferent) system?
attributes coded for about a stimulus include modality/quality (such as vision, olfaciton, somato-, taste, etc), intensity, location of stumulus, and duration.
what is transduction?
transduction is the transformation of physical energy (sensory stimulus) to a neural signal
T/F : the unique expieruence assoc w a particular modality begins at the Receptor
True. the experience of a modality (i.e. taste, vision, audition, somatosensory, olfaction, visceral..) starts at the receptor
T/F receptors have sensory specificity where they have a limited range of sensitivity
True. REceptors are sensory specific.. they have a limited range of sensitivity and cannot detect all different types of modalities, ranges, etc.. diff receptors pick up different attributes.
Name the 5 different types of sensory receptors
the 5 differnt types of sensory receptors are:
- mechanoreceptor
- photoreceptor
- chemoreceptor
- thermoreceptor
- nociceptor
mechanoreceptor: : invovled w/ somatosensory, audition, balance
photoreceptor: vision
chemoreceptor: somatosensory, olfaction, taste
thermoreceptor : somatosensory
nociceptor = pain
there are two types of transduction (stimulus energy conversion ot neural signal).. do they both involve synaptic transmission?
No. The two types of transduction are Direct transduction where there is NO synapse (meanng the receptor is at the terminal of the afferent nerve that goes directly to the CNS)–
the other type of transduction is “molecular interaction” where the receptor cell Does have a Synapse with the afferent neuron that goes to the CNS,. (2 cell system: receptor and afferent neuron to CNS)
** different modalities of stimulus operate by one or both of the 2 mechanisms:
(see sensory principles packet, p2)
T/F ENaCs is a direct tranduction system common for taste sensation
True. ENacS- the epithelial sodium (Na+) channels open up due to mechanoreceptor sense of stretch allowing Na_ to flood in, AP is stimulated due to depolarization and Ca++ enters the cell, causing the release of ATP NuT
Taste also employs molecular interaction style (2 cell) tranduction for sweet, amino acids (umami). and bitter submodalities of stimuli. Moleuclar interaction tranduction employs the receptor cell and SYNAPSE w afferent neuron, and G-protein signalling and TRP channel that allows Ca++ entry – depolariztion and ATP as NuT release (same as direct trnaduction sequence of events)
the relationship bt stimulus intentsity and neural + peceptual responses can be linear (aka, direct.. more intensity noticed as more) = graded potentials …
however, threshhold for AP stimulation is not linear, IS CURVE-linear (“S” shape)
further, there has been a link showing that higher threshhold (such as ability to smell a quality) is indicative of disease state — specifically, lack of olfaction of butanol correlates with onset of Alzheimer’s = clinically significant
T/F different neurons have different sensitivieies – meaning they detect different ranges of attributes , and this limitiation is important for coding of qulity oof stimulus and location, intensity etc of stimulus (( activated neurons help form a map of hte stimulus characteristics)
True. further, neurons also exhibit Lateral inhibition, so that if the neuron is receving very strong signals it quiets its neighbors via inhibition so that its own signal is delivered without modulation. this helps sends a more clear and unmuddled signal to the CNS
T/F Rapidly adapting and slow adapting “” describe the reaction of a neuron to a maintained stimulus. Descrbie answer
True. Rapidly adapting and slow adapting descrbie the different reaction of a neuron to a maintainied stimulus.
Rapidly adapting are neurons that fire upon initiation and then stop firing (or very few during) until the stimulus is off andhten they fire to signal off == On-OFF rreaciton
versus,
slow-adapting neurons which fire off AP at same rate from initiation to entire duration of stimulus. imp to signal slow changes, and imp for prolonged actions like maintian posture during long times fo standing
4 types of nerve endings are Meissner corpusle, Merke;’s disk, pacinian corpuscle, and ruffini ending. Assign these as slow adapting or fast adapting neuron endings, AND descirbe their submdality snesitivity
Meissner corpusle - spatial discrimiation = Rapid a. 1
pacinian corpusle - vibration = rapid a. 2
merkel’s disk - pressure = slow adapting 1
ruffini ending = skin stretch = SA2
recall rapidly adapting = ON- OFF signal (ap at start and finish of stimulus)
vs. slowly adapting where AP fired for entire stimulus duration, good for prolonged sdetection and sense of small changes
Different lobes are associated to the different sense modalities. Match the following lobe with the modality it wires
Parietal lobe :: Auditory::
Frontal lobe:: Visual cortex:
Insular cortex: Taste
Temporal lobe: somatosensory
occipital lobe olfaction
the following lobes of the brain are matched with modality of stiumuls they wire:
frontal lobe: olfaction parietal lobe: somatosensory occipital lobe: vison temporal lobe : auditory insular cortex : taste
there are three brain maps that locate different qualities of the odalities they wire:
- somatotropic map of the parietal (homonculus) maps the body representation
- tonotropic map is an auditory pitch representation
- retinotopic mnap i a visual field representation ..
can these maps change?
Yes, the maps are important for cortical organzaiton (connection of brain to body and the environment around).. but these maps can change due to some PLASTICITY.
- skills can lead to greater representation of areas (ex, musicians with more cortical activity in fingers during playing than others untrained.. ). injury (such as loss of some fingers) can also lead to plasticity as other parts of the body are used to compensate and gain more cortical wiring activity
- sprouting is one way this plasticitiy occurs (the axonal ends sprout and grow into other body areas nearby)
