Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

15. The Special Senses

Introduction to Special Senses

Anatomy & Physiology

15. The Special Senses

Introduction to Special Senses

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Problem 21

Textbook Question

Displacement of stereocilia toward the kinocilium of a hair cell
(a) Produces a depolarization of the membrane
(b) Produces a hyperpolarization of the membrane
(c) Decreases the membrane permeability to sodium ions
(d) Increases the membrane permeability to potassium ions
(e) Does not affect the membrane potential of the cell

Verified step by step guidance

Understand the structure and function of stereocilia and kinocilium in hair cells. Stereocilia are small, hair-like projections on the surface of hair cells in the inner ear, and the kinocilium is the tallest stereocilium. These structures are involved in mechanotransduction, converting mechanical stimuli into electrical signals.

Recognize that displacement of stereocilia toward the kinocilium opens mechanically gated ion channels located at the tips of the stereocilia. This movement is caused by mechanical forces such as sound waves or head movements.

Recall that the opening of these ion channels allows positively charged ions, primarily potassium (K⁺) and calcium (Ca²⁺), to flow into the hair cell. This influx of ions leads to a change in the membrane potential of the cell.

Understand that the influx of potassium and calcium ions causes depolarization of the hair cell membrane. Depolarization is a reduction in the difference in charge between the inside and outside of the cell, making the inside less negative.

Conclude that displacement of stereocilia toward the kinocilium produces a depolarization of the membrane, which is essential for the generation of electrical signals that are transmitted to the auditory or vestibular nerve.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Stereocilia and Kinocilium Function

Stereocilia are hair-like projections on hair cells in the inner ear that play a crucial role in the auditory and vestibular systems. When stereocilia are displaced toward the kinocilium, the tallest stereocilium, it triggers a mechanical response that leads to the opening of ion channels, ultimately affecting the cell's membrane potential.

Depolarization and Hyperpolarization

Depolarization refers to a decrease in the membrane potential, making the inside of the cell more positive, while hyperpolarization is an increase in membrane potential, making the inside more negative. The direction of stereocilia movement determines whether the hair cell depolarizes or hyperpolarizes, influencing neurotransmitter release and signal transmission to the brain.

Ion Permeability Changes

Changes in ion permeability, particularly to sodium (Na+) and potassium (K+), are critical in the function of hair cells. Displacement of stereocilia can increase the permeability to potassium ions, allowing K+ to flow into the cell, which contributes to depolarization. Conversely, it can also affect sodium permeability, influencing the overall excitability of the hair cell.