PHYS Introduction to Sensory Systems

Question 1

Receptor classifications corresponding to origin stimulus

Answer 1

• Exteroception – information from external environment
• Proprioception – relationship of our body to external environment
• Interoception – information from internal environment.

Question 2

Receptor classifications based on activating stimulus

Answer 2

• Mechanoreceptors – respond to stretch or deformation
• Photoreceptors – respond to light
• Chemoreceptors – respond to chemicals (incl. osmoreceptors)
• Thermoreceptors – respond to changes in temperature
• Nocireceptors – respond to painful/damaging stimuli

Question 3

Compare direct and indirect method of stimulus response

Answer 3

Direct - physical stimulus & response via structural change in membrane w receptor cells
Indirect - instead of receptor cells causing a structural change in membrane, molecules, like G proteins are instead activated.

Question 4

Coding for stimulus intensity/strength

Answer 4

Increase responding ion channel no. -> increase no. APs sent

Question 5

Coding for stimulus timing/repetition

Answer 5

(E.g., closely spaced APs for fine textured cloth vs widely spaced APs for coarse sandpaper).

Question 6

Coding to enable change/adaptation

Answer 6

APs decrease in intervals sent for constant stimulus vs fluctuant stimulus (E.g., constant fire alarm vs fluctuant sound of a piano).

Question 7

Coding for location

Answer 7

Different locations have different receptor strengths (e.g., 2 point discrimination experiment - 2 points experienced on fingers, but 1 point experienced on back due to reduced receptor fields - > sensory homunculus).