Sensory Physiology Flashcards
Perception
Integration of sensory information with previously learned information and other sensory inputs!
Adequate stimulus
The proper stimulus for that sensor!
Eye – light
Labeled line principle
A nerve transmits only one kind of info!
Eye transmits light…
If you feel pressure on the eye it will signal as light!
How do you increase intensity of a stimulus?
Increase the frequency of the actin potentials!
Compression (in reference to stimulus)
How is it measured..?
Give numbers?
Log relationship between frequency and the stimulation!
Measured with Weber:Fechner principle
Numbers: 10-1 100-2 500-2.7 1000 - 3
Adaptation
What are the two types?
Process to decrease AP when there is a maintained stimulus
- Tonic = no adaptation (ex. Blood pressure)
- Physic = slow and rapid adaptation!
Accommodation
Change in AP frequency via changes in ion channels!
Acuity is what?
Example?
Sharpness!!
Ability to detect 2 pins instead of 1
How do receptive field and lateral inhibition affect acuity?
Receptive field == want a narrower receptive field to have a higher acuity
Lateral inhibition == this increases acuity by inhibiting nerves around the actual stimulus so you feel the strongest stimulus at the point!
5 types of touch receptors!!
List in the order that is best to remember what they do… one word description for each…
Meissner - light
Merkel - heavy
Ruffini - PDL
Pacinian - vibrate
Hair follicle receptors
MMRP
parts of the eye!
3 at the back
5 at the front
BACK
- sclera = tough
- choroid = vasculature
- retina = photoreceptors
FRONT - iris = contracts - cornea = 75% focusing - lens = 25% focusing .... connects to ciliary body via the zonule fibers!
Distant vs near vision!
What happens to the ciliary muscles, zonule fibers, and the lens?
DISTANT
- ciliary muscles relax, the zonule fibers tighten, and the lens is flat!
NEAR
- ciliary muscles contract, the zonule fibers relax, and the lens is fat!
Presbyopia?
Stiffening of the lens with age
Macula lutea and fovea centralis
Macula lutea = area on the retina with the MOST visual acuity! About 1mm squared
Fovea centralis = area of direct focus!
Pigment epithelial cells?
What is a condition where this is missing?
Located behind the photoreceptors and help gather scattered light…
These increase visual acuity
Albinism == this is missing!
What does the optic nerve affect on the retina?
It creates a blind spot that is filled in by the brain!
Rods vs cones
Where are each located?
Which are more numerous?
What are each used for?
What is the pigment cell in each?
What colors?
Rods – located in periphery
Used for low light areas
More numerous!
Pigment cell = rhodopsin!
Cones
– located at macula lutea and fovea centralis
Used for color!
Pigment cell = opsin
(R,G,B)
3 structures of the outer ear!
Pinna
External auditory canal (lined with wax glands)
Tympanic membrane
= vibrates
2 parts of the middle ear
Ossicles
- malleus, incus, stapes
Eustachian tube
- connects inner ear to pharynx
- important for equilizing and drainage
What transducts AP from sound?
Cochlea!
Describe the organ of corti
Basilar membrane and gelatinous tectorial membrane
Hair cells in the middle
Stereocilia on hair cells cause opening of K+ channels which cause an AP
Why is the AP sent from the ear unique?
It is caused by influx of K+… this influx occurs because of the high amount of K+ in this fluid!
Frequency encoding…
Where is frequency the highest/lowest?
Pitch depends on the area of basilar membrane that is stimulated
Highest frequency near the oval window!
2 parts of the vestibular system…
Which does which type of movement?
What moves in each part?
Saccule and utricle == linear movement! (Position of the head)
*the otoliths move over the hairs
Semicircular canals = rotary movement
*the capula moves over the hairs
What are the different taste receptors?
What types of channels are they?
Salty == Na+ and Cl- channels!
Sour, Bitter, Sweet, Umami (savory) are all G-protein coupled receptors!!
Umami or savory == tasting glutamate!
