Lesson 3: Audition
Light hits a photoreceptor in the eye and causes the the cell to fire an action potential. That cell is connected to two other cells, which also fire action potentials. What does this form of up-regulation refer to? (A) Amplification (B) Sensory Adaptation (C) Habituation (D) Proprioception
(A) Amplification Because the stimulus, light, caused multiple action potentials to occur, the response to the stimulus is up-regulated and refers to Amplification
In the Cochlea, what structure moves back and forth and is responsible for transmitting an electrical impulse via the auditory nerve to the brain? (A) Cilia (Hair Cells) (B) Oval Window (C) Circular Window (D) Stapes
(A) Cilia (Hair Cells) In the cochlea, Cilia or Hair cells move back and forth and are responsible for transmitting an electrical impulse via the auditory nerve to the brain.
The Basilar Membrane of the Organ of Corti contains Cilia (Hair Cells) known as the ___________. (A) Hair Bundle (B) Basilar Group (C) Tectorial Hairs (D) Cochlear Knot
(A) Hair Bundle The Basilar Membrane of the Organ of Corti contains Cilia (Hair Cells) known as the Hair Bundle.
_____________ frequency sounds activate the base of the cochlea, while _____________ frequency sounds activate the apex of the cochlea. (A) High, Low (B) High, High (C) Low, High (D) Low, Low
(A) High, Low High frequency sounds (1600 Hz) activate the base of the cochlea, while Low frequency sounds (25 Hz) activate the apex of the cochlea.
What structures make up the Middle Ear? (A) Malleus, Incus, and Stapes (B) Pinna, Auditory Canal, and Tympanic Membrane (C) Semicircular Canals, and Cochlea (D) Stapes, Pinna, Auditory Canal, and Oval Window
(A) Malleus, Incus, and Stapes The Malleus, Incus, and Stapes (Ossicles) make up the Middle Ear.
*CRB* Based on the previous card's description, which of the following classes of receptors communicate position from your proprioception spindles to your brain? (A) Mechanoreceptors (B) Chemoreceptors (C) Kinesoreceptors (D) Nociceptors
(A) Mechanoreceptors Because those receptors in the muscle spindles are activated by stretching (mechanical stress), they are mechanoreceptors.
*check* What is the part of the human brain that is referred to as the map of the human body? (A) Sensory Strip (B) Midbrain (C) Somatosensory Homunculus (D) Sensory Cortex
(A) Sensory Strip The Sensory Strip is the part of the parietal lobe that houses the five senses, and can be mapped out as homunculi (map of body in brain). Somatosensory homunculi located in sensory strip
*check* Which structure of the brain receives sensory input from the entire human body? (A) Sensory Strip (B) Cerebellum (C) Pons (D) Medulla
(A) Sensory Strip The Sensory Strip is the structure of the brain that receives sensory input from the entire human body. Sensory strip contains a somatosensory homunculus. And once info comes from body, it will go to a specific part of that sensory strip called hominculus.
What is the range of Frequencies in terms of Hz that humans can hear? (A) 10 Hz - 10,000 Hz (B) 20 Hz - 20,000 Hz (C) 30 Hz - 30,000 Hz (D) 40 Hz - 40,000 Hz
(B) 20 Hz - 20,000 Hz 20 Hz - 20,000 Hz is the range of Frequencies that a human can hear.
*CRB* Which part of the Central Nervous System would use this information from proprioceptors to improve its coordination? (A) Substantia Nigra (B) Cerebellum (C) Cerebrum (D) Spinal Column
(B) Cerebellum The Cerebellum, which coordinates movement, would integrate information from proprioceptors.
Put the Auditory Ossicles in order from first to vibrate to last to vibrate? I. Incus II. Malleus III. Stapes (A) I > II > III (B) II > I > III (C) III > II > I (D) III > I > II
(B) II > I > III 1st. Malleus 2nd. Incus 3rd. Stapes
Order the following steps of a Cochlear Implant from first to last: I. Transmitter sends electrical impulse to the Receiver. II. Stimulator sends electrical impulse to the Cochlea which converts the electrical impulse to a neural impulse that is sent to the brain. III. Sound is converted to an electrical impulse by Speech Processor. IV. Receiver sends electrical impulse to the Stimulator. (A) I > III > IV > II (B) III > I > IV > II (C) II > IV > III > I (D) IV > II > III > I
(B) III > I > IV > II Sound is converted to an electrical impulse by Speech Processor > Transmitter sends electrical impulse to the Receiver > Receiver sends electrical impulse to the Stimulator > Stimulator sends electrical impulse to the Cochlea which converts the electrical impulse to a neural impulse that is then sent to the brain.
What is the relationship between the frequency and wavelength of a sound wave? (A) Proportional (B) Inverse (C) Linear (D) Exponential
(B) Inverse As the frequency of a sound wave increases, the wavelength decreases. Likewise, as the frequency of a sound wave decreases, the wavelength increases.
*CRB* Which of the following are not one of the areas involved in auditory pathways? (A) Medial Geniculate Nucleus (B) Lateral Geniculate Nucleus (C) Superior Olive (D) Inferior Colliculus
(B) Lateral Geniculate Nucleus The LGN is involved in vision. The MGN, Superior Olive, and Inferior Colliculus are all involved in processing auditory information.
In which part of cerebral cortex is the sensory strip located? (A) Frontal Lobe (B) Parietal Lobe (C) Temporal Lobe (D) Occipital Lobe
(B) Parietal Lobe The Sensory Strip is located in the Parietal Lobe.
What structures make up the External/Outer Ear? (A) Malleus, Incus, and Stapes (B) Pinna, Auditory Canal, and Tympanic Membrane (C) Semicircular Canals, and Cochlea (D) Stapes, Pinna, Auditory Canal, and Oval Window
(B) Pinna, Auditory Canal, and Tympanic Membrane The Pinna, Auditory Canal, and Tympanic Membrane make up the External/Outer Ear.
For audition to occur, the stimulus, _________________, must be present and the receptors, __________________, must transduce the stimulus to neural signals. (A) Pressurized sound waves, Pressurized sound waves (B) Pressurized sound waves, Hair Cells (C) Hair Cells, Hair Cells (D) Hair Cells, Pressurized Sound Waves
(B) Pressurized sound waves, Hair Cells For audition to occur, Pressurized Sound Waves must be present and Hair Cells must transduce the stimulus to neural signals.
What refers to a change over time of the responsiveness to a constant stimulus and thus represents a down regulation of a sensory receptor in the body? (A) Amplification (B) Sensory Adaptation (C) Feature Detection Theory (D) Proprioception
(B) Sensory Adaptation Sensory Adaptation refers to a change over time of the responsiveness to a constant stimulus and thus represents a down regulation of a sensory receptor in the body.
Sound waves are represented graphically by peaks and troughs. If a wave has a high wavelength, its peaks must be: (A) close to each other. (B) far away from each other. (C) very tall. (D) very short.
(B) far away from each other. If a wave has a high wavelength, its peaks must be far away from each other.
_________ are the small filaments that make up the hair bundle of the Organ of Corti and are connected to one another by __________. (A) auditory nerve, kinocilium (B) kinocilium, tip links (C) stapes, tip links (D) cilia, kinocilium
(B) kinocilium, tip links The Kinocilium are the small filaments that make up the hair bundle of the Organ of Corti, and are connected to one another by Tip Links.
Which structure in the ear allows the Brain to differentiate between 2 different sounds? (A) Tympanic Membrane (B) Stapes (C) Cochlea (D) Ossicles
(C) Cochlea The Cochlea allows the Brain to differentiate between 2 different sounds.
*CRB* Which of the following are also types of proprioceptors? I. Golgi tendon organs II. Ossicle receptors III. Joint capsule receptors (A) I only (B) I and II only (C) I and III only (D) I, II and III
(C) I and III only Common proprioceptors are: I. Golgi Tendon organs II. Proprioception spindles III. Joint capsule receptors
*CRB* Which of the following are proper descriptions of how a change in pitch (with constant loudness) would be encoded by the inner ear? I. The number of auditory nerves activated would change. II. The basilar membrane would vibrate in different areas. III. Different auditory nerves would be activated. (A) II only (B) I and II only (C) II and III only (D) I, II and III
(C) II and III only Basilar tuning states that different frequencies (pitches) will increase vibrations at different parts of the basilar membrane. This means different auditory neurons will be activated.
*CRB* Based on the previous card, the K+ channels opened by the kinocilium belong to what class of channels? (A) Ligand gated (B) Voltage Gated (C) Mechanically Gated (D) Voltage Gated with Inactivation State
(C) Mechanically Gated Because the stretching of tip links is permitting the flow of K+ through the channels, this is a mechanically gated channel.
Which structure in the cochlea is responsible for preventing cochlear fluid from returning to the oval window (elliptical window), while simultaneously moving the fluid towards the round window (circular window)? (A) Cilia (Hair Cells) (B) Stapes (C) Organ of Corti (D) Auditory Nerve
(C) Organ of Corti The Organ of Corti is responsible for preventing cochlear fluid from returning to the oval window (elliptical window), while simultaneously moving the fluid towards the round window (circular window).
Which structure of the brain receives all auditory information from the cochlea and is separated into regions which detect different frequency sounds? (A) Occipital Lobe (B) Cerebral Cortex (C) Primary Auditory Cortex (D) Secondary Auditory Cortex
(C) Primary Auditory Cortex The Primary Auditory Cortex of the brain receives all auditory information from the cochlea and is separated into regions which detect different frequency sounds.
What structures make up the Inner Ear? (A) Malleus, Incus, and Stapes (B) Pinna, Auditory Canal, and Tympanic Membrane (C) Semicircular Canals, and Cochlea (D) Stapes, Pinna, Auditory Canal, and Oval Window
(C) Semicircular Canals, and Cochlea The Semicircular Canals, and Cochlea make up the Inner Ear.
Without basilar tuning, humans would not be able to differentiate between sounds. What is the mapping of different frequency sounds in the brain referred to as? (A) Auditory mapping (B) Basilar mapping (C) Tonotopical mapping (D) Geographical mapping
(C) Tonotopical mapping Tonotopical mapping refers to the mapping of different frequency sounds in the BRAIN, and thus allows distinct areas in the brain to process distinct frequencies. Towards the front of the brain corresponds to the apex of the cochlea (high frequency), and towards the back of the brain corresponds to the base of the cochlea a(low frequency
What refers to the process in which the cochlea distinguishes between varying frequencies and is maintained by the brain? (A) Frequency Processing (B) Signal Detection Theory (C) Parallel Processing (D) Auditory Processing
(D) Auditory Processing Auditory Processing refers to the process in which the cochlea distinguishes between varying frequencies and is maintained by the brain.
Put these steps of the middle ear audition pathway in order: I. Malleus, incus and stapes vibrate in that order. II. Oval window (elliptical window) starts to vibrate and moves cochlear fluid. III. Tympanic membrane vibrates. (A) I > II > III (B) II > I > III (C) III > II > I (D) III > I > II
(D) III > I > II Tympanic membrane vibrates. > Malleus, incus and stapes vibrate in that order. > Oval window (elliptical window) starts to vibrate and moves cochlear fluid.
The _______ funnels sound into the ___________, where it will travel to the _______________, where the sound waves are then converted into ossicle vibrations. To fill in the blanks, please choose 3 from the following options: - Semicircular Canals - Pinna - Tympanic Membrane (eardrum) - Auditory Canal - Stapes
1. Pinna 2. Auditory Canal 3. Tympanic Membrane (eardrum) The Pinna funnels sound into the Auditory Canal, where it will travel to the Tympanic Membrane, where the sound waves are converted into ossicle vibrations.
If there were no cochlear fluid, would audition be possible? How would the hair cells be affected?
Any vibrations from the stapes to the oval window would move air, whose movement would have a significantly smaller effect on hair cells; thus, they wouldn't reach threshold, making audition impossible.
Why can a cochlear implant help patients with sensorineural hearing loss (aka nerve deafness), but not cochlear or downstream nervous issues?
A cochlear implant functions by stimulating the oval window of the cochlea when its transmitter is activated. It can overcome conduction errors from the middle ear, but can't fix errors downstream of the oval window.
What do we mean when we say location of a stimuli?
Based on dermatomes. Dermatomes are areas o the skin that have a spinal nerve innervating it and based on which dermatome is firing, we can know location of the stimulus
In order to distinguish between high and low frequencies, the brain utilizes the cochlea, particular something known as:
Basilar Tuning- as sound reaches cochlea, it will stimulate different parts of the basilar membrane
*CRB* True or false? A sensory neuron going from the ear to the brain firing more or less rapidly would encode a change in the pitch of a sound.
False. A sensory neuron going from the ear to the brain firing more or less rapidly would encode a change in the LOUDNESS of a sound.
True or False? In addition to the cochlea, the brain uses tectorial tuning to distinguish between high and low frequency sounds.
False. The brain uses Tonotopic Mapping to distinguish between high and low frequency sounds.
*CRB* True or false? The loudness of sound is represented by the period of the wavelength, and the pitch is represented by the wavelength.
False. The loudness of sound is represented by the AMPLITUDE of the wavelength, and the pitch is represented by the wavelength.
*CRB* True or false? The stapes-oval window junction is similar to a gas-piston system, and the perilymph inside the cochlea is easily compressed by the stapes' vibrations.
False. The stapes-oval window junction is similar to a gas-piston system. However, liquids are not compressible, so the perilymph moves back and forth within the cochlea.
What do we mean when we say intensity of a stimuli?
How quickly the neurons fire over a period of time. So over 10 seconds , two different stimuli may present two different intensities
Why is Sensory adaptation important in terms of cells becoming over excited?
If a cell is overexcited, it can cause damage and most likely cell death. Sensory adaptation is a necessary response by receptors to avoid over-excitement of cells.
What is the difference between oval and round widnow?
Oval window is connected to stapes and vibrates causing the initial movement of perilymph inside the cochlea. Round window vibrates and helps propagation of mechanical wave inside the cochlea
What is the benefit of down regulation or sensory adaption to a stimulus?
Prevents cell from possibly dying and also prevents brain from being overwhelmed with information
What is the role of the organ of corti in the cochlea?
Prevents fluid in cochlea from going back through oval window and instead through the circular window
What are the main differences between proprioception and kinesthesia?
Proprioception is more subconscious and cognitive, like a general awareness of one's balance/position. Kinesthesia is more behavioral, with the body detecting its movements and consciously improving its movements
If a whole bunch of capsacin was injected to one of the TrpV1 receptors, what would happen overtime?
Receptors would stop firing and become desensitized overtime. And if more capsacin was injected past the point of desensitization, the receptor would die in that area and wont relay anymore pain or heat
In a crowded emergency room, many different voices and sounds combine to make complex sound waves. How does the auditory system break down complex sound waves into its component parts?
Since the complex sound waves are made of components with different frequencies, in the cochlea, the different components will travel to different lengths and stimulate hair cells on different parts of the cochlea.
Sound waves are discriminated and sorted by its frequency inside the fluid-filled cochlea. Would a lower or higher frequency sound wave travel farther into the cochlea?
Sound waves of a lower frequency would travel farther into the cochlea.
What is the benefit of having basilar tuning?
The brain can differentiate between sounds of high and low frequencies
The tip links of the hair bundles are attached to what?
The gates of a potassium channel
The three types of TrpV1 fibers, A-B, A-D, and C vary in size due to different levels of myelination. How does their relative myelination affect their function?
The more myelinated a fiber is, the wider the axon is. This increases conductance by decreasing resistance, so the more myelinated fibers transmit their messages faster.
As the energy of a sound wave traveling through the ear dissipates, what happens to the movement of fluid inside the cochlea?
The movement of fluid inside the cochlea slows down and eventually stops, causing that particular sound to not be transmitted to one's brain anymore.
The first thing that sound waves hit as they enter the ear is known as what?
The pinna- the outer part of the ear
Describe how sound waves travel after it hits the pinna:
The sound waves get funneled by the pinna and then goes through the auditory canal (external auditory meatus), and then it hits the ear drum. The ear drum vibrates then causes the three little bones to vibrate. Firs the malleus, then the incus then the stapes. The stapes is connected to an oval window which vibrates causing fluid in the chochlea to move around sending signals to brain as hair cells get pulled on
Proprioception spindles are often compared to springs. How do these receptors in muscles communicate position to your brain?
These sensors are inside the muscles and will stretch with them. Once stretched, spindles fire signals to the brain, and the combination of spindles from all muscles are integrated, allowing you to subconsciously know your body position.
When eating spicy foods, people can feel pain as their TrpV1 receptors are activated. Why can capsaicin and similar chemicals activate these receptors?
TrpV1 receptors are chemical sensors, so the capsacin molecules must be similar in structure to molecules released by cellular damage. Thus, spicy foods might feel "painful"
True or false? For the TrpV1 receptors, A-Beta (A-B) fibers are the fastest, while C fibers are the slowest, due to their different levels of myelination.
True. A-Beta (A-B) fibers are the fastest, while C fibers are the slowest, due to their different levels of myelination.
True or False: The Organ of Corti is composed of two membranes.
True. The Organ of Corti is composed of two membranes, the upper (tectorial) and lower (basilar) membrane.
*CRB* True or false? The basilar membrane is covered with hair cells, but those hairs project from the basilar membrane to contact the tectorial membrane.
True. The basilar membrane is covered with hair cells, but those hairs project from the basilar membrane to contact the tectorial membrane.
Both nociception and thermoception (pain and temperature sensation, respectively) use TrpV1 receptors to send those signals to the brain. When something pokes us for example, it causes cellular damage. How do these receptors convert cellular damage into neural signals?
When a cell is damaged, it releases chemical signals that diffuse to the nearest TrpV1 receptor. When it binds it causes the receptor to cause an action potential that will eventually reach the brain through on of the different types of fibers of the TrpV1 receptors
Describe how a pressurized sound wave is formed as someone claps their hands?
When someone goes to clap their hands, there are many air molecules between their hands. As the hands get closer, there is less space for the air molecules to move and they thus become compressed. This compression causes the air molecules to become pressurized and thus to relieve this pressure, the air molecules try to escape. This escape of air molecules causes areas of high and low pressure which are known as pressurized sound waves.
What do we mean when we say timing of a stimuli?
When the stimuli starts and when it ends. Three types: Slow adapting: action potential will start firing really quickly and overtime as the area gets used to the stimulus, the action potential firing rate slows down decreasing the intensity Non adapting: the entire time a stimulus is being applied, there is no change in the firing rate Fast adapting: fires real quickly when stimulus starts and then stops firing and the fires again when stimulus stops
The tip link of a kinocilium is attached to the gates of a K+ channel. Explain how an action potential is generated when fluid begins to move inside the cochlea.
When tip links start to be pushed back and forth by fluid movement inside the cochlea, they stretch and opens up potassium gates which allows K+ to enter inside the cell. Voltage-gated Ca2+ cells consequentially become activated allowing Ca2+ to begin flowing into the cell as well, causing an action potential, which stimulates the spiral ganglion cell and ultimately activates the auditory (cochlear) nerve that goes to the brain
Give a real life example of sensory adaptation.
You walk into the library and notice a strong smell, similar to BBQ. After about an hour sitting in the library your smell receptors would no longer notice such a strong smell of BBQ. Mmmm... BBQ...
How close sound waves are to each other is known as:
frequency
What is the purpose of vibration of the structures in the ear?
to amplify the forces because inside the cochlea is perilymph and at the air fluid boundary before the cochlea, there is a considerable amount of resistance to the mechanical waves and to overcome that resistance so that the fluid can move inside the cochlea, vibrations occur The pinna, eardrum, and ossicles amplify the mechanical waves by about 90x
Note that the cochlear nerve also merges with the :
vestibular nerve
