Lab #8: Sensory Physiology

Question 1

How many sensory neurons does it take to take information to the brain?

Answer 1

3

Question 2

Different areas of the brain perceive ____________ ____________ _________

Answer 2

specific sensory information

Question 3

Where are sensory receptors located?

Answer 3

on the dendrite of ONLY the first sensory neuron (in a series of neurons)

Question 4

What is the function of a sensory receptor?

Answer 4

captures sensory information (external stimulus)

Question 5

How does a sensory receptor carry out its function?

Answer 5

takes sensory stimuli information (transduce) and converts it into an AP

Question 6

What is it called when a sensory receptor takes sensory stimuli information and converts it into an AP?

Answer 6

transduce into an AP

Question 7

Define modality

Answer 7

form of external stimulus

Question 8

Each unique type of sensation is called…

Answer 8

a sensory modality

Question 9

Each sensory neuron carries information for _____ modality

Answer 9

one

Question 10

_______ is converted into an AP

Answer 10

modality

Question 11

What type of receptor would be involved in light modality?

Answer 11

photoreceptors

Question 12

Where are general/cutaneous receptors located?

What modalities do general/cutaneous receptors respond to?

Answer 12

location: near epithelial surfaces; all over body

respond to: touch, pressure, temperature

Question 13

For general/cutaneous receptors, the receptor is _____ of the first sensory enruon

Answer 13

part

Question 14

Where are special senses receptors located?

What modalities do special senses receptors respond to?

Answer 14

location: sensory organs, but only found in specific locations (ex. eye contains photoreceptors and nose contains olfactory receptors)

LES
- light/vision
- equilibrium
- sound/hearing

Question 15

For special senses receptors, the receptor is _________ from the first sensory neuron

Answer 15

separate

Question 16

All receptors ultimately _______ to a stimulus

Answer 16

adapt

(decrease in response to stimulus after some time: slowly/quickly)

Question 17

What are tonic receptors?

Provide examples

Answer 17

• respond at constant rate as long as stimulus applied
• adapt slowly to stimuli (ex: pain)

Question 18

What are phasic receptors?

Provide examples

Answer 18

• respond with burst of activity, but quickly reduce response to constant stimulation
• adapt quickly to stimulu (ex: smell, touch)

Question 19

What is a generator potential (GP)

Answer 19

are sensory receptors equivalent to an EPSP

• are produced in response to adequate stimuli -> if threshold reached -> AP generated

Question 20

Why, in terms of receptive fields, do the different areas have different two-point thresholds?

Answer 20

each receptive field in the skin varies depending on the density of receptors in that region

Question 21

Which of the areas that we tested had the largest receptive fields?

Which of the areas that we tested had the smallest receptive fields?

Answer 21

largest: upper arm

smallest: fingertip

Question 22

Why is it difficult for the brain to discern multiple stimuli coming from the same receptive field?

Answer 22

all stimulus coming from a given receptive field goes to the same location in the brain

Question 23

Which of the areas that you tested would have the largest brain region dedicated to it? Explain

Answer 23

fingers because they have a smaller receptive field, meaning there are more neuronal pathways = more brain area required

Question 24

Larger receptive fields have…

Smaller receptive fields have…

Answer 24

lower localization ability

finer sense of tactile discrimination

Question 25

Define conduction deafness

Answer 25

when the conduction of the sound wave through the outer/middle ear is impaired

Question 26

Define neural deafness

Answer 26

when ear structures in the inner ear, cochlea, or cochlear nerve to the brain regions responsible for hearing are compromised

Question 27

In the webster test, where would an individual with normal ears hear the tone louder? Why?

Where would an individual with conduction deafness hear the tone louder? Why?

Where would an individual with neural deafness hear the tone? Why?

Answer 27

normal ear: tone is equally loud, so sound will be localized as coming from the midline

conduction deafness: louder in deaf ear because in normal ear sound is partially masked by environmental noise

neural deafness: louder in normal ear because neural activity is essential for hearing

Question 28

In the Rinne test, with a person who has normal ears, where is the sound perceived longer? air or bone

With a person who has conduction deafness, where is the sound perceived longer?

With a person who has neural deafness, where is the sound percieved longer?

Answer 28

normal ears: longer by air bc the threshold for air conduction is lower than bone

conduction deafness: longer by bone because something is affecting the conduction of soundwaves

neural deafness: longer by air

Question 29

One patient (#1) takes a visual acuity test using a snellen chart. Their results read: 10/100

Another patient (#2) takes the same test and their results read: 30/20

Who has better vision? Explain why and be detailed.

Answer 29

patient #2 has better vision

patient #1 has poor vision because the top number refers to the distance (ft) that they are standing from the chart to read a specific line. the bottom number indicates how far the majority of people can read the specific line. patient #1 can only read the specified line from 10 feet away, while other people are able to read the line from 100 feet away.

patient #2 has the best vision because he can read the specified line from 30 feet away, while the majority of people can only read from 20 feet away.