Inner Ear Function and Sensory Perception

📋 Course Outline

1. Otoliths and Maculae
2. Hair Cells and Membranes
3. Cochlear Duct Structure
4. Sound Wave Mechanics
5. Neural Pathways in Hearing
6. Olfaction and Age
7. Gustation Disorders
8. Vision Aging Changes
9. Vertigo Causes
10. Hearing Loss Types

📖 1. Otoliths and Maculae

🔑 Key Concepts & Definitions

• Otoliths: Calcium carbonate crystals (ear stones) embedded in the otolithic membrane of the utricle and saccule, responsible for detecting linear acceleration and head position relative to gravity.

• Macula: A sensory epithelium within the utricle and saccule containing hair cells and supporting cells; the utricular macula detects horizontal movement, while the saccular macula detects vertical movement.

• Hair cells: Sensory receptors with stereocilia and a kinocilium that transduce mechanical stimuli into nerve signals when distorted by movement or gravity.

• Otolithic membrane: Gelatinous layer overlaying hair cells in the maculae, embedded with otoliths, which shift with head movements to stimulate hair cells.

• Sensory response to head position: Changes in head orientation cause otoliths to shift, distorting hair cell processes, which sends signals to the brain about body position and movement.

📝 Essential Points

• The utricle and saccule contain maculae with hair cells that detect linear accelerations and static head positions relative to gravity.