SPHSC 461

Exam 1

NOTE: EXPECT ABOUT 8-10 QUESTIONS ON THE EXAM

Definitions. (4 pt each)

1. auditory transduction

2. endocochlear potential

3. rate-place code

4. phase locking

5. adaptation

True or false? (2 pt each)

6. _____ The transfer function of the middle ear resembles a low-pass filter with a cutoff of about 250 Hz.

7. _____ Ions pass freely through the reticular lamina.

8. _____ The tectorial membrane is loosely coupled to the rest of the organ of Corti at its outer edge.

9. _____ The ear does not code the absolute starting phase of the components in a complex sound.

10. _____ The spread of excitation along the basilar membrane with increasing sound intensity could provide a code for sound intensity.

Short answers

11. Sketch a cross-section through the cochlear duct. Show and label the scala vestibuli, the scala media, the scala vestibuli, inner hair cells, outer hair cells, pillar cells, basilar membrane, tectorial membrane, reticular lamina. (10 pt)

12. What is the role of the stereocilia’s tip links (or trandsuction links) in transduction? (5 pt)

13. Draw the transfer function of the external ear head related transfer function for a sound source located at 0 degrees azimuth. (10 pt)

14. What information does the phase-locked response of auditory nerve fibers provide to the brain? (5 pt)

15.1.What is the dynamic range problem in hearing? (10 pt)

16.15. What is the major function of the middle ear? What is the most important way that the middle ear accomplishes that function? (10 point)

17.16. a. What is the function of the outer hair cells? (5 pt)

b.

Name two ways in which the code for sound sent from the ear to the brain would change if outer hair cells were lost. (10 pt)

18. Draw the interval histogram of an auditory nerve fiber with a best frequency of 1000 Hz. (10 pt)