Sensory Physiology

Question 1

Perception

Answer 1

Integration of sensory information with previously learned information and other sensory inputs!

Question 2

Adequate stimulus

Answer 2

The proper stimulus for that sensor!

Eye – light

Question 3

Labeled line principle

Answer 3

A nerve transmits only one kind of info!

Eye transmits light…
If you feel pressure on the eye it will signal as light!

Question 4

How do you increase intensity of a stimulus?

Answer 4

Increase the frequency of the actin potentials!

Question 5

Compression (in reference to stimulus)

How is it measured..?

Give numbers?

Answer 5

Log relationship between frequency and the stimulation!

Measured with Weber:Fechner principle

Numbers:
10-1
100-2
500-2.7
1000 - 3

Question 6

Adaptation

What are the two types?

Answer 6

Process to decrease AP when there is a maintained stimulus

1. Tonic = no adaptation (ex. Blood pressure)
2. Physic = slow and rapid adaptation!

Question 7

Accommodation

Answer 7

Change in AP frequency via changes in ion channels!

Question 8

Acuity is what?

Example?

Answer 8

Sharpness!!

Ability to detect 2 pins instead of 1

Question 9

How do receptive field and lateral inhibition affect acuity?

Answer 9

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!

Question 10

5 types of touch receptors!!

List in the order that is best to remember what they do… one word description for each…

Answer 10

Meissner - light
Merkel - heavy
Ruffini - PDL
Pacinian - vibrate

Hair follicle receptors

MMRP

Question 11

parts of the eye!

3 at the back

5 at the front

Answer 11

BACK

• sclera = tough
• choroid = vasculature
• retina = photoreceptors

FRONT
- iris = contracts
- cornea = 75% focusing
- lens = 25% focusing
.... connects to ciliary body via the zonule fibers!

Question 12

Distant vs near vision!

What happens to the ciliary muscles, zonule fibers, and the lens?

Answer 12

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!

Question 13

Presbyopia?

Answer 13

Stiffening of the lens with age

Question 14

Macula lutea and fovea centralis

Answer 14

Macula lutea = area on the retina with the MOST visual acuity! About 1mm squared

Fovea centralis = area of direct focus!

Question 15

Pigment epithelial cells?

What is a condition where this is missing?

Answer 15

Located behind the photoreceptors and help gather scattered light…

These increase visual acuity

Albinism == this is missing!

Question 16

What does the optic nerve affect on the retina?

Answer 16

It creates a blind spot that is filled in by the brain!

Question 17

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?

Answer 17

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)

Question 18

3 structures of the outer ear!

Answer 18

Pinna
External auditory canal (lined with wax glands)

Tympanic membrane
= vibrates

Question 19

2 parts of the middle ear

Answer 19

Ossicles
- malleus, incus, stapes

Eustachian tube

• connects inner ear to pharynx
• important for equilizing and drainage

Question 20

What transducts AP from sound?

Answer 20

Cochlea!

Question 21

Describe the organ of corti

Answer 21

Basilar membrane and gelatinous tectorial membrane

Hair cells in the middle

Stereocilia on hair cells cause opening of K+ channels which cause an AP

Question 22

Why is the AP sent from the ear unique?

Answer 22

It is caused by influx of K+… this influx occurs because of the high amount of K+ in this fluid!

Question 23

Frequency encoding…

Where is frequency the highest/lowest?

Answer 23

Pitch depends on the area of basilar membrane that is stimulated

Highest frequency near the oval window!

Question 24

2 parts of the vestibular system…

Which does which type of movement?

What moves in each part?

Answer 24

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

Question 25

What are the different taste receptors?

What types of channels are they?

Answer 25

Salty == Na+ and Cl- channels!

Sour, Bitter, Sweet, Umami (savory) are all G-protein coupled receptors!!

Umami or savory == tasting glutamate!