Neurobiology Exam 2

sounds enter the ear as pressure waves which…

push and pull the eardrum, causing it to vibrate.

if a sound is…, a muscle pulls the stirrup away from the most sensitive parts.

too loud

Each of the 30,000 sensors picks a differeny part of the sound and sends it to…

the brain

The external ear consists of the part on the outside of the head called the… plus the …, which leads to the eardrum.

pinna, ear canal

The middle ear consists of a series of miniscule bones - the malleus, incus and stapes - connecting the eardrum to the cochlea. The primary function of the middle ear is to…

amplify sound

The principal elements for converting sounds into neural activity are found on the basilar membrane. This membrane vibrates in response to sound, with the apex displaced maximally by … sound, and the base displaced maximally by … sound.

low-frequency, high-frequency

Ion channels on the stereocilia of auditory hair cells are activated by…

mechanical energy

The correct order for the pathway from the cochlea to the auditory cortex.

Cochlea, cochlear nucleus, superior olivary nucleus, inferior colliculus, medial geniculate nucleus, auditory cortex

Which statement is false?

Tonotropic organization occurs at the inferior colliculi, but not the cochlea

What is a measure of sound intensity, perceived as loudness?

Decibel

T or F: the frequency of sounds is perceived as loudness

False (The frequency of sounds is measured in cycles per second, or hertz (HZ), and perceieved as pitch

… is the number of cycles per second in a sound wave, measured in hertz

Frequency

The external ear…

helps capture, focus, and filter sounds. the shaped of the external ear provides cues about the distance of the source of a sound. the auditory canal is part of the external ear.

What is the external part of the ear called?

the pinna

Which of the following statements is true of IHC afferents?

They convey to the brain the action potentials that provide the perception of sounds

Which of the following is a reason why each successive loaction along the basilar membrane shows its strongest response to a different frequency of sound?

The basilar membrane is tapered

Even a tiny bend of the stereocilia in the ear produces a large and rapid depolarization of the hair cells. Which of the following causes this depolarization?

The operation of a special type of large and nonselective ion channel found on stereocilia

The … of the middle ear concentrate and amplify vibrations from the air.

ossicles

The part of the inner ear that ultimately converts vibrations from sound into neural activity is the …

Cochlea

Which complementary theories that explain the ways in which the pitch of sounds is encoded?

Temporal coding theory and Place coding theory

T or F: temporal coding is most evident at lower frequencies, up to about 4,000 Hz

True

What are binaural cues that are analyzed by the human auditory system to detect the loaction of a sound source.

Interaural temporal differences and Interaural intensity differences

Identify the tyoes of interaural temporal differences (ITDs)

Ongoing phase disparity and Onset disparity

By adulthood, the portion of primary auditory cortex where music is first processed, called …, is more than twice as large in professional musicians as in non musicians.

Heschl’s gyrus

Which of the following is a disorder characterized by the inability to discern tunes accurately or to sing?

Amusia

… is defined as very-low-frequency sound, generally below the 20 Hz threshold for human hearing.

Infrasound

T or F: intensity difference is defined as a percieved difference in loudness between the two ears, which the nervous system can use to localize a sound source.

True

The functions of auditory cortex from an ecological perspective

Mammalian species employ a huge range of requencies in their vocalizations, from infrasound in elephants and whales to ultrasound in bats and porpoises and many other species. These sounds have been shaped by evolution to serve special purposes. For example, many species of bats analyze the reflected echoes of their ultrasonic vocalizations to navigate and hunt in the dark. At the other end of the spectrum, elephants emit ultra-low-frequency alarm calls that are so powerful that they travel partly through the ground and are detected seismically by other elephants and yet are so nuanced that the elephants can distinguish human-related threats from bee-related threats and can use their “rumbles” to identify potential mates

What is a hearing impairment in which the ears fail to convert sound vibrations in air into waves of fluid in the cochlea?

Conduction deafness

In the context of restoring auditory stimulation in deafness, what is truw of cochlear implants?

These devices can detect sounds and selectivly stimulate nerves in different regions of the cochlea

What is true of cortical deafness?

It involves bilateral lesions of auditory cortex

What are types of central deafness?

Cortical deafness and Word deafness

T or F: Most cases of central deafness involve a simple loss of auditory sensitivity.

False

In the context of hearing loss, … involves selective trouble with speech sounds despite normal speech and normal hearing for nonverbal sounds, whereas … involves more-complete impairment, struggling to recognize all complex sounds, whether verbal or nonverbal.

word deafness; cortical deafness

Sensorineural deafness

treatments for sensorineural deafness focus on the use of prostheses, sensorineural deafness is most often the result of permanent damage or destruction of hair cells, sensorineural deafness can be caused by medical problems such as infections and adverse drug effects

Sasha visits a doctor after experiencing hearing loss. The doctor finds that Sasha’s ear is unable to convert aound waves in the air into waves of fluid within the cochlea. What treatment methods should the doctor best use to treat Sasha?

surgical freeing up of the ossicles if they are fused together, use of Teflon prosthetics to restore the transmission of sound vibrations to the cochlea, use of hearing aids that employ electronic amplification

A sensation of noises or ringing in the ears not caused by external sound is referred to as…

tinnitus

T or F: Anyone listening to something for more than 5 hours per week at 89 dB or louder is exceeding workplace limits for hearing safety

True

What is the primary function of the vestibular system of the human body?

Giving the sense of balance

What are the components of the human vestibular system?

The utricle, the saccule, and semicircular canals

The three semicircular canals of the vestibular system are oriented in the three different axes in which the head can rotate

nodding up and down (Pitch), shaking from side to side (yaw), and tilting left or right (Roll)

T or F: A human being’s sense of balance is primarily the product of the pressure exerted by the feet on the ground

False

The receptors of the vestibular system are …. The cilia of these cells are embedded in a gelatinous mass inside an enlarged chamber called the …

Hair cells; ampulla

What factor causes motion sickness?

Movements of the body that one cannot control

T or F: according to the sensory conflict theory, people feel bad when they receive contradictory sensory messages, especially a discrepancy between vestibular and visual information

True

In the context of tastes, … is described as the full-bodied, thick, mouth-filling quality of some foods

Kokumi

T or F: The numerous little bumps on our tongues are taste buds

False (They are actually papillae, tiny lumps of tissue that increase the surface area of the tongue

Identify the kinds of papillae that occur in different locations on the tongue

Circumvallate papillae, fungiform papillae, foliate papillae

T or F: Each papila houses only one taste bud

False (Taste buds, each consisting of a cluster of 50-150 taste receptor cells, are found buried within the walls of the paillae. A single papila may house several such taste buds)

T or F: Each taste cell is sensitive to all the five basic tastes

False (Each taste cell is sensitive to just one of the five basic tastes

The taste projections of the gustatory system ultimately extend to the…

somatosensory cortex

… are fine fibers that extend from taste receptor cells into a tiny pore, where they come into contact with substances that can be tasted, called …

Microvilli; Tastants

The combination of T1R2 and T1R3, two members of the T1R family, makes a receptor that selectively detects … tastants

Sweet

In contrast with many other receptor cells in the body, olfactory receptor cells…

are periodically renewed

Humans have approximately… different olfactory receptor genes in the genome, although only about half of them appear to be fully functional

1000

What is the best description of olfactory receptor molecules?

G-protein linked receptors

T or F: Our ability to percieve a large number of different odors is what produces the complex array of flavors thst we normally think of as tastes

True

T or F: One glomerulus recieves input exclusively from one specific class of odorant receptors

True (Each glomerulus recieves inputs exclusively from olfactory nerurons that are expressing the same type of olfactory receptor)

What is the only sensory modality that synapses directly in the cortex rather than havinf to pass through the thalamus?

smell

T or F: Humans possess one of the most developed and functional vomeronasal organs

False (The vomeronasal organ is either vestigial or absent in humans, and almost all of our V1R and V2R receptor genes have become nonfunctional “pseudogenes” over evolutionary time)

Olfactory information is conveyed to the brain via the axons of mitral cells, which extend from the glomeruli to various targets. What are among the targets?

The prepyiform cortex, the hypothalamus, the amygdala

What is the reason why the smell of something might make you remember your childhood etc.?

The same limbic structures that act as targets for olfactory inputs are also closely involved in memory and emotion.

What indicates the differences between humans and dogs in term of olfaction?

Dogs have 100-300 million olfactory receptor neurons, whereas humans have 6 million olfactory receptor neurons

Olfactory receptor neurons are found in the …

olfactory epithelium

Each olfactory neuron extends a fine, unmyelinated axon into the nearby olfactory bulb of the brain, where it terminates on one specific … -a spherical clump of neurons - out of the thousands that exist in the olfactory bulb.

glomerulus

T or F: within the 5-10 square centimeters of olfactory epithelium that we possess, about 6 million olfactory receptor neurons are found

True

What are the two measures in terms of which a pure tone is physically described?

Frequency and amplitude

Things most relevant to the inner ear

The cochlea is a spiral of three parallel canals: the scala vestibuli, the scala media, and the scala tympani. The scala media contains the receptor system, called the organ of Corti, that converts vibration from sound into neural activity. It consists of three main structures: the auditory sensory cells, called hair cells, which bridge between the basilar membrane and the overlying tectorial membrane; an elaborate framework of supporting cells; and the auditory nerve terminals that transmit neural signals to and from the brain.

Which parts of the ear are crucial in protecting agaisnt extremely loud noises that may otherwise be damaging to the ear?

The stapedius and the tensor tympani

T or F: While walking around town, Rita can detect whether a car that is honking is somewhere in front or is on an overpass above. This is because spectral cues arriving at the hills and valleys of the external ear procide the inferior coliculus of the brain with critical information. about the elevation of a sound source.

True (spectral cues provide critical information about the vertical localization (or elevation) of a sound source.

What is true of the external ear?

The shape of the external ear provides cues about the distance of the source of a sound, the auditory canal is part of the external ear, the external ear helps capture, focus, and filter sounds

Nadia, a scientist, is studying how the human auditory system perceives a 300 Hz sound. What experimental outcome is Nadia likely to observe?

The pitch of a sound is determined by the rate of firing of auditory neurons

Santiago experiences the sound of a dog barking at a distance. However, the loudness percieved is different between the two ears. identify the reasons why these differences occur.

these differences occur because the head casts a sound shadow and because one ear is pointed more directly toward a sound source.

Conduction deafness

Usually invloves a middle ear problem that blocks sound vibrations from reaching the inner ear

Sensorineural deafness

There is a problem with the structure - especially the cochlea - that convert sound vibrations into neural activity and project to the brain

Central deafness

damage to auditory brain structures can affect hearing in various ways

The doctor finds that broad swaths of hair cells in Alexa’s ears have been destroyed. What should the doctor do to restore Alexa’s hearing?

Place cochlear implants in her ears

a doctor diagnoses Martin with sensorineural deafness. What could likely be the causes of Martin’s deafness?

nearby gunshots, industrial noise, overamplified music

A human being’s sense of balance is the product of the …, relying on several small structures that adjoin the … and are known collectively as the …

inner ear; cochlea; vestibular system

“vestibular information is crucial for planning body movements, maintaing balance against gravity, and smoothly directing sensory organs like the eyes and ears toward specific locations, even when an individual’s body is itself in motion” What is most likely to be inferred from this statement?

Outputs from the vestibular nuclei project in a complex manner to motor areas throughout the brain.

What is the sensory system that detects taste?

the gustatory system

Syeda, a researcher, is studying about the gustatory system. Syeda focuses on a taste that often signals the presence of toxins and learns that members of the T2R family of receptor proteins appear to function as the receptors of this taste. What is true about this taste?

the cells that sense this taste exhibit broadly tuned sensitivity to any substance that has this taste and the receptors for this taste are more like metabotropic receptors than iontropic receptors

What are true of olfactory neurons?

Humans have around 6 million olfactory receptor neurons in the olfactory epithelium and the sense of smell starts with olfactory receptor neurons

What is a chemical signal that is released outside of the body of an animal and affects other members of the same species?

A pheromone

Clara sprays an air freshner in a room and is immediately able to detect the fragrance. How is the information of the air freshener’s fragrance conveyed to Clara’s brain?

via the axons of mitral cells

People who have visual agnosia…

cannot see everyday objects

The brain uses… to be able to interpret information transmitted through vision.

structural and semantic processing

People who have visual agnosia can adapt by … as complementary aids.

using other senses

When light reaches the retina, it first strikes the layer containing the … cells.

ganglion

Information from the left visual field projects to … of the brain; information from the right visual field projects to the … of the brain

the right side; the left side

The primary relay nucleus between the retina and the cerebral cortex is called the…

lateral geniculate nucleus

The receptive surface at the back of the eye that contains photoreceptors and other neurons is called the…

retina

The process by which the ciliary muscles adjust the lens to bring nearby objects into focus is called…

accommodation

The inability to focus faraway images on the retina due to elongation of the eyeball is called…

myopia

The central portion of the retina, which is packed with the highest density of photoreceptors and is the center of our gaze, is called the…

fovea

The region of the retina devoid of photoreceptors because ganglion cell axons and blood vessels leave the eye there is called the…

optic disc

The point at which parts of the two optic nevers cross the midline is called the…

optic chiasm

The change in the shape of the lens is controlled by the … muscles inside the eye

ciliary

T or F: movement of the eyes is controlled by the extraocular muscles, three pairs of muscles that extend from the outside of the eyeball to the bony socket of the eye

True (The extraocular muscles control the movement of eye)

The tendency of rods and cones to adjust their light sensitivity to match current levels of illumination is called photoreceptor…

Adaption