CSD 357 - Midterm

Set 1: Vestibular System - SCCs vs. Utricle/Saccule

Flashcard 1

• Q: What type of movement do semicircular canals (SCCs) detect?

• A: SCCs detect rotational (angular) acceleration via endolymph movement in response to head rotation.

Flashcard 2

• Q: What is the primary function of the utricle and saccule?

• A: They detect linear acceleration and gravitational pull, utilizing the otolithic membrane and otoconia.

Flashcard 3

• Q: Which vestibular structure is key for horizontal acceleration, and provide an example?

• A: The utricle; it detects horizontal acceleration, like forward and backward movement in a car.

Flashcard 4

• Q: What role do the maculae and otolithic membrane play in the vestibular system?

• A: They provide inertia, detecting tilt and straight-line movement by sensing direction and intensity.

Set 2: Ear Development and Hearing Function

Flashcard 1

• Q: At what stage does hearing begin, and how is it conducted?

• A: Hearing begins at 25 weeks gestation through bone conduction.

Flashcard 2

• Q: How does the tympanic membrane develop, and what are its layers?

• A: It forms from ectoderm, mesoderm, and endoderm, with layers being outer (skin), middle (fibrous), and inner (mucous membrane).

Flashcard 3

• Q: What changes occur in the hearing threshold from birth to 10 years?

• A: Significant improvements from birth to 4 years, slower gains from 4 to 10, and no improvements beyond that.

Set 3: Cochlea and Auditory System Basics

Flashcard 1

• Q: Describe tonotopic organization in the cochlea.

• A: The cochlea encodes different frequencies in an organized manner, with high frequencies near the base and low frequencies near the apex.

Flashcard 2

• Q: What is phase locking and at what frequencies is it most effective?

• A: Phase locking is when nerve fibers fire in sync with a sound wave's phase, effective for frequencies below 1,000 to 4,000 Hz.

Flashcard 3

• Q: What are the two types of auditory afferent neurons and their functions?

• A: Type I neurons connect to Inner Hair Cells, encoding sound detail, while Type II neurons connect to Outer Hair Cells, modulating sound sensitivity.

Set 4: Key Structures of the Ear

Flashcard 1

• Q: What are the main parts of the auricle (pinna) and their functions?

• A: Helix (outer rim), antihelix (inner ridge), tragus, antitragus, concha; these structures collect and funnel sound into the ear canal.

Flashcard 2

• Q: What is the role of the external auditory meatus (ear canal)?

• A: It directs sound waves to the tympanic membrane and helps protect the ear through temperature and humidity regulation.

Flashcard 3

• Q: How does the tympanic membrane contribute to hearing?

• A: It converts sound waves into mechanical vibrations, essential for transmitting sound to the middle ear.

Set 5: Middle Ear and Impedance Matching

Flashcard 1

• Q: Name the three amplification mechanisms that overcome air-to-fluid impedance mismatch.

• A: Areal ratio advantage (25 dB boost), curved membrane (3 dB), and ossicle lever action (2.2 dB).

Flashcard 2

• Q: Describe the middle ear reflex and its function.

• A: The reflex stiffens the ossicles to reduce transmission of low-frequency sounds in response to loud noise, protecting the inner ear.

Flashcard 3

• Q: How does the Eustachian tube assist the ear?

• A: It equalizes air pressure on both sides of the tympanic membrane, aiding middle ear function.