CSD 373

What part of the temporal bone is located in the outer ear?

Squamous of temporal bone

What is the most important dB for plotting audiograms in this course?

dB HL

What are the functions of the Eustachian tube?

Pressure equalization and fluid drainage.

What part of the temporal bone is located in the middle ear?

Mastoid process of temporal bone.

What is the typical angle of an adult's Eustachian tube?

45 degree angle.

How is a child's Eustachian tube typically positioned?

Flat and 180 degrees.

What does dB HL stand for?

Hearing Level; used to plot audiograms.

What does dB IL refer to?

Intensity Level.

What is dB SL?

Sensation Level.

What does dB SPL mean?

Sound Pressure Level.

How are high and low frequencies organized in the cochlea?

High frequencies at the base and low frequencies at the apex.

What is the fluid similar to intracellular fluid in the inner ear?

Endolymph.

What are the characteristics of inner hair cells?

3500 in single row, chalice shaped, and centralized nucleus.

How many rows of outer hair cells are there in the cochlea?

Three rows.

What does the term 'impedance matching' refer to in the middle ear?

33 dB gain/increase.

What is the function of the auditory nerve?

To innervate the sensory hair cells.

What is the fluid in the scala tympani?

Perilymph.

What is the shape of the malleus?

Hammer-shaped.

What role does Reissner's membrane play in the cochlea?

Separates scala vestibuli from scala media.

What is the purpose of the acoustic reflex?

Protection and reduction of distortion of a person's own voice.

What occurs during rarefaction?

Decreased air pressure.

At what part of the cochlea does the helicotrema occur?

At the apex.

What is the primary function of the cochlea's outer hair cells?

They act as a cochlear amplifier.

What are the three parts of the inner ear?

Cochlea, vestibule, and semicircular canals.

Where is the Umbo located?

It is part of the tympanic membrane (eardrum).

What happens when two waveforms combine with the same starting phase?

They create increased amplitude.

What does the term 'tonotopic' refer to in the cochlea?

Organization where high frequencies are at the base and low frequencies are at the apex.

What energy type is present in the outer ear?

Acoustic energy.

Is the Eustachian tube naturally open or closed?

Closed.

What liquid is present in the scala vestibuli?

Perilymph.

What is the role of the stria vascularis?

It provides blood flow, nutrients, and electrical charge to the cochlear system.

What does 'phase locking' refer to in neural discharge?

Neural discharges occur in the same phase as the stimulus, valid up to 4000Hz.

How does energy change from the middle ear to the inner ear?

From mechanical vibrations to hydromechanical.

What part of the temporal bone is located in the inner and middle ear?

Petrous part of temporal bone.

What are the functions of the outer ear?

Funnels sound, provides transfer function, and protects the ear.

What is found in the scala media?

Endolymph.

What is the primary shape of the outer hair cells?

Cylindrical, forming a W shape.

How are the inner hair cells characterized?

Single row, chalice shaped, and only afferent fibers synapse directly on them.

What structure distinguishes the organ of Corti?

It contains both inner and outer hair cells.

What is the main function of the middle ear?

To convert acoustic vibrations into mechanical vibrations.

What does 'active process of cochlea' refer to?

The function of outer hair cells responding to basilar vibration.

What does 'tonotopically organized' mean?

The basilar membrane's organization corresponding to frequency; high frequencies at base, low frequencies at apex.

What color is used to represent the left ear on audiograms?

Blue.

What color is used to represent the right ear on audiograms?

Red.

What does mechanical vibrations refer to in the inner ear?

The transition of sound energy to hydromechanical energy.

What is the function of the semicircular canals?

Balance and spatial orientation.

What is the role of the auditory nerve (8th nerve)?

Transmits auditory information to the brain.

What happens to the cochlear hair cells when sound waves arrive?

Bending of stereocilia generates action potential.

What are the three types of fluids present in the cochlea?

Endolymph, perilymph, and cerebrospinal fluid-like fluid.

What does complex waveforms result from?

The combination of two or more simple waves.

What happens to sound waves that are 180 degrees out of phase?

They cancel each other out.

What does the term 'scalas' refer to in the cochlea?

The three chambers: scala vestibuli, scala media, and scala tympani.

What are the auditory ossicles?

Malleus, incus, and stapes.

What role does the tectorial membrane serve?

Helps in the function of hair cells in the cochlea by providing structure.

What is the cone of light?

A reflective surface seen during otoscopy examination of the tympanic membrane.

What liquid is found in the scala media?

Endolymph.

What is the soft tissue that separates the parts of the tortuous cochlea?

Cochlear duct (scala media).