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 15

Textbook Question

How do the hair cells of the crista ampullaris detect rotation of the head?

Verified step by step guidance

Understand the anatomy of the crista ampullaris: The crista ampullaris is located within the ampulla of each semicircular canal in the inner ear. It contains hair cells embedded in a gelatinous structure called the cupula.

Learn about the role of the semicircular canals: The semicircular canals are filled with endolymph, a fluid that moves in response to head rotation. Each canal is oriented in a different plane to detect rotational movements in three dimensions.

Explore the mechanism of detection: When the head rotates, the inertia of the endolymph causes it to lag behind the movement of the canal. This relative motion pushes against the cupula, bending the hair cells within the crista ampullaris.

Understand how hair cells respond: The bending of the hair cells causes their stereocilia to deflect. Depending on the direction of deflection, ion channels in the hair cells open or close, altering the release of neurotransmitters to the associated sensory neurons.

Connect to the brain's interpretation: The sensory neurons transmit signals to the brain via the vestibular nerve. The brain interprets these signals to perceive the direction and speed of head rotation, allowing for balance and spatial orientation.

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Key Concepts

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

Crista Ampullaris

The crista ampullaris is a sensory structure located within the semicircular canals of the inner ear. It contains hair cells that are crucial for detecting angular motion or rotation of the head. When the head rotates, the endolymph fluid within the canals moves, causing the hair cells to bend and generate nerve impulses that inform the brain about the direction and speed of the rotation.

Hair Cells

Hair cells are specialized sensory cells found in the inner ear that play a vital role in the auditory and vestibular systems. They have hair-like projections called stereocilia that respond to mechanical stimuli. In the context of the crista ampullaris, the bending of these stereocilia due to fluid movement leads to the depolarization of the hair cells, which then transmit signals to the brain regarding head movement.

Vestibular System

The vestibular system is a complex structure in the inner ear responsible for maintaining balance and spatial orientation. It includes the semicircular canals, otolith organs, and associated neural pathways. The information gathered from the crista ampullaris and other components of the vestibular system is integrated by the brain to help coordinate movements and maintain equilibrium during head rotations and other activities.