Sensory systems 1 Flashcards
what are the 4 qualities of sensory input
Modality (type)
Intensity
Duration
Location
what are 1st, 2nd, 3rd order neurons
1st- specialized type of physical energy for each receptor
2nd- More complex analysis (ex basic shape of object)
3rd.- most advanded processing
difference bw 2 types of blind sight
retinal blindness- light can enter eyes but once it makes it to retina there is no processing
Cortical blindness- optic nerves/tracts work fine but prob in visual cortex. Can sense vision to some degree.
what does the topographic organization of the sensory input refer to
Neighboring regions in the periphery are maintained in the CNS (neighboring mechanoreceptors are neighboring in the cns)
how do PSP get activated in receptors (ex mechanotransductor)
mechanoreceptors sensitive to pressure
-when there is a change in pressure it causes sodium channels to open which depolarizes cell
what is activity code
ex. light touch will only cause a couple channels to open where harder touchwill cause an increased number to open (population code)
How quick do pancian corpuscles adapt and methods on how they do
- very quick
- ion channels open/close quickly
- Pancian corpusle damped by tissue (will move corpuscle to side)
what is labled line code
certain types of sensory input is carried on specific lines (tracts)
ex. friendly touch vs noxious touch
what is pattern code(and ex)
- taste
- spectrum of flavour of something
what are nociceptors and how do they get into heighted states
Responds directly to tissue damage or stim that has potential to damage tissues
when cells are dammaged chem mediators release chems that sensitize nociceptors
What temps do thermoreceptors detect and how does the info travel
cold- bw -20 is
hot- up to 45
travel on specific labeled line tracts
what receptors for touch found on smooth skin
Meissners
merkels
what doe joint capsul mechanoreceptors detect
sheering
bending
muscle pulls
deep ressure
What do muscle spindles detect and when do they cause mm to fire
Sensitive to strethc
-when there is no stretch detected will cause gamma fibes to cause contraction
what do cone and rod cells detect
cones- color
rods- b+ww
when there is light what happens in the light cells (and what does it cause to the channels in the end; general)
- light breaks down rhodopsin to retinal + opsin
- retinal activates G pro
- G pro activates c GMP phosphodieterase which decreases cGMP which causes sod channels to close
what happens when light is there in 1st and 2nd order neurons
retinal- rhodopsin brocken down. Causes decreased cGMP, so na channels closed and no glutamate release.
Bipolar- no NT allow cGMP to build up on bipolar which opens sod channels on ON receptor which releases glutamate to ganglion cell
What happens when there is no light in 1st and 2nd order neurons
retinal- no rhodopsin released so cAMP increases allowsing sod channels to open and glutamate release
Bipolar
ON- cGMP decreased closes sod channels
OFF- cGMP thrives allowing sod channels to open and releases NT to ganglion.
What do horizontal cells do
Ensure there is no incorrect activaion (off cells are off in presence of light)
-enhances contrast
what is a low tolerance to hot foods associated w
increased nociceptors on the tongue
salts and acis activate this type of channel whereas Carbs lead to this type of channel
Salts + acids activate ionotropic channels
Carbs- activate g protiens
What 2 tastes have cross over in high conc
High conc of sour substances may cross over and acttivate salt receptor
what is the CNS refelx for hearing
Tightens mm attached to ossicles to dampen sound
What happens when there is an unexpected loud sound in the inner ear
Causes spastic type of mm contraction that causes ringing in ear due to vibration of ossicle
where are high and low frquencies heard in the chochlea
basilar end for high frequencies (shorter hair follicles)
Apical end for low frequeincies
what is the longest hair cell called and which way of bending causes depolarization and hyperpolarization
largest is kinocillim
Bending towards= depolarization
Bending away= hyperpolarization
What happens with ppl w R sided Strabismus
R eye might have down and out
May start to tilt head to R to compoensate
How do we localize sound (2)
interneural intensity dif- difference in intensity bw ears
Itraoral time dif- time dif bw two ears
Where is interneural and intraoral time diff processed
Interneural intensity- Lat sup olivary nucleus
Intraoral- Medial sup olivary dif
max delay of tiem dif ears can detect and what frequencies are better localized
800usec
> 1000Hz
