Other sensory systems

Question 1

Sound waves:

Answer 1

are periodic compressions of air, water, or another medium.

b. Sound waves vary in amplitude and frequency.

Question 2

Amplitude:

Answer 2

Intensity of a sound wave. In general, sounds of greater amplitude sound louder, but exceptions occur.

Question 3

Frequency:

Answer 3

Number of compressions per second, measured in hertz (Hz) of a sound.
- Most adult humans can hear sounds ranging from 15 to almost 20,000 Hz

Question 4

Pitch:

Answer 4

The perception of frequency (the higher the frequency of a sound, the higher its pitch).

Question 5

timbre:

Answer 5

meaning tone quality or tone complexity.

Question 6

Prosody:

Answer 6

Conveying emotional information by tone of voice

Question 7

The anatomy of the ear is described in terms of three regions:

Answer 7

the outer ear, the middle ear, and the inner ear.

Question 8

pinna:

Answer 8

The outer ear includes the pinna (structure of flesh and cartilage attached to the side of the head) and the auditory canal. The pinna helps us locate the source of a sound by altering reflections of sound waves.

Question 9

tympanic membrane (eardrum):

Answer 9

The middle ear is comprised of the tympanic membrane (eardrum), which vibrates at the same frequency as the sound waves that strike it. Sound waves reach the tympanic membrane through the auditory canal. The tympanic membrane is attached to three tiny bones (hammer, anvil, and stirrup).

Question 10

oval window and cochlea:

Answer 10

The inner ear consists of the oval window, which receives vibrations from the tiny bones of the middle ear, and the cochlea, which contains three fluid-filled tunnels: the scala vestibuli, scala media, and scala tympani.

Question 11

hair cells/ auditory receptors:

Answer 11

f. The auditory receptors (hair cells) lie between the basilar membrane and the tectorial membrane in the cochlea.
* *p.65

Question 12

Pitch Perception

Answer 12

your ability to understand speech or enjoy music depends on your ability to differentiate among sounds of different frequencies.

Question 13

Place Theory:

Answer 13

Each area along the basilar membrane is tuned to a specific frequency and vibrates whenever that frequency is present. Each frequency activates hair cells at only one place along the basilar membrane, and the brain distinguishes frequencies by which neurons are activated.
- This theory has a downfall in that various parts of the basilar membrane are bound too tight for any part to resonate like a piano string.

Question 14

Frequency Theory:

Answer 14

We perceive certain pitches when the basilar membrane vibrates in synchrony with a sound, causing the axons of the auditory nerve to produce action potentials at the same frequency.
- Although the downfall is that in the simplest form of a neuron, though variable, is typically about 1/1000 second, so the maximum firing rate of a neuron is about 1000 Hz, far short of the highest frequencies we hear

Question 15

The current theory is a modification of both place and frequency theories:

Answer 15

For low frequency sounds (below 100 Hz), the basilar membrane does vibrate in synchrony with the sound wave in accordance with frequency theory. The pitch of the sound is identified by the frequency of impulses and the loudness is identified by the number of firing cells.

Question 16

Volley principle of pitch discrimination:

Answer 16

The auditory cortex as a whole can have volleys of impulses up to about 4000 per second, even though no individual axon approaches this frequency alone.

• The volley principle is believed to be important for pitch perception below 4000 Hz, although it is unclear how the brain uses this information.
  e. For high frequency sounds (above 4000 Hz), we use a mechanism similar to place theory. High frequency vibrations strike the basilar membrane, causing a traveling wave. This causes displacement of hair cells near the base (where the stirrup meets the cochlea). Low frequency sounds produce displacement farther along the membrane.

Question 17

Tone deafness or amusia:

Answer 17

A disorder where individuals are seriously impaired at detecting small changes in frequency. Many relatives of those with amusia have the same condition. It is associated with a thicker than average auditory cortex in the right hemisphere but fewer than average connections from the auditory cortex to the frontal cortex.

Question 18

Primary auditory cortex (area A1):

Answer 18

Ultimate destination of auditory information is located in the superior temporal cortex. Area A1 also is important for auditory imagery. Similar to the visual system, the auditory system needs experience to develop normally. Both constant noise and lack of exposure to sound will impair the development of the auditory system.
- Damage to the A1 does not leave someone deaf (different from damage to V1); it may hinder the ability to recognize combinations or sequences of sounds, like music or speech.

Question 19

Conductive or middle-ear deafness:

Answer 19

Failure of the bones of the middle ear to transmit sound waves properly to the cochlea. Conductive deafness can be caused by diseases, infections, or tumorous bone growth near the ear. This deafness can be corrected by surgery or hearing aids.

Question 20

Nerve or inner-ear deafness:

Answer 20

Damage to the cochlea, hair cells, or auditory nerve that causes a permanent impairment in hearing in one to all ranges of frequencies. Nerve deafness can be inherited or caused by prenatal problems and early childhood disorders.

Question 21

Tinnitus:

Answer 21

Frequent or constant ringing in the ear. Tinnitus is often produced by nerve deafness. It is a phenomenon similar to phantom limb, where axons corresponding to other parts of the body may invade the brain area previously responsive to sounds, especially high-frequency sounds. Presumably axons representing the jaw and neck invade their auditory cortex

Question 22

Sound Localisation:

Answer 22

Determining the direction and distance of a sound requires comparing the responses of the two ears.
- Adult humans are accurate at localization for frequencies above 2000 to 3000 Hz, and less accurate for progressively lower frequencies.

Question 23

The Mechanical Senses:

Answer 23

The mechanical senses respond to pressure, bending, or other distortions of a receptor

Question 24

Vestibular Sensation:

Answer 24

1. The vestibular organ monitors head movements and directs compensatory movements of the eyes. It is critical for eye movements and maintaining balance.
2. The vestibular organ consists of the saccule, utricle, and three semicircular canals.
3. Calcium carbonate particles (otoliths) lie next to hair cells excite them when the head tilts in different directions.

Question 25

The three semicircular canals:

Answer 25

are filled with a jellylike substance and lined with hair cells. Acceleration of the head causes this substance to push against hair cells, which in turn causes action potentials from the vestibular system to travel via part of the eighth cranial nerve to the brainstem and cerebellum.

Question 26

The somatosensory system:

Answer 26

involves the sensation of the body and its movements, including discriminative touch, deep pressure, cold, warmth, pain, itch, tickle, and the position and movements of joints.

Question 27

Pacinian corpuscle:

Answer 27

detects sudden displacements or high-frequency vibrations on the skin.

Question 28

Capsaicin: a chemical found in hot peppers such as jalapeños, stimulates the receptors for painful heat.

Answer 28

a chemical found in hot peppers such as jalapeños, stimulates the receptors for painful heat.

Question 29

dermatome:

Answer 29

Each spinal nerve has a sensory component and a motor component. Each sensory spinal nerve innervates a limited area of the body called a dermatome.

Question 30

Sensory information from the spinal cord is sent to:

Answer 30

the thalamus before traveling to the somatosensory cortex in the parietal lobe.

d. The somatosensory cortex receives information primarily from the contralateral side of the body.
e. Damage to the somatosensory cortex impairs body perceptions. A patient with Alzheimer’s who exhibited such damage had trouble putting her clothes on correctly

Question 31

Emotional pain:

Answer 31

a. Painful stimuli also activate a path that goes through the reticular formation of the medulla and then to several of the central nuclei of the thalamus, the amygdala, hippocampus, prefrontal cortex, and cingulate cortex.
b. These areas react not to the sensation but to its emotional associations.
c. Hurt feelings can be like real pain (You can relieve hurt feelings with pain-relieving drugs such as acetaminophen (Tylenol®)!

Question 32

Opioid Mechanisms:

Answer 32

released by the brain to dull prolonged pain after you are alerted of danger.
iii. Opioids bind to receptors in the spinal cord and periaqueductal gray area to block the release of substance P and decrease prolonged pain.

Question 33

Endorphins:

Answer 33

the transmitters that attach to the same receptors as morphine. Different endorphins (naturally released by the brain) relieve different types of pain.

Question 34

Gate Theory:

Answer 34

Information not related to pain travels to the spinal cord and closes the “gates” for each pain message, thereby modulating the subjective experience of pain.
- Although gate theory turned out to be wrong, the general principle is valid: nonpain stimuli modify the intensity of pain.

Question 35

Sensitization of Pain:

Answer 35

a. The body also has mechanisms to increase pain after tissue has been damaged and inflamed.
b. Pain sensitization is a result of the body releasing histamine, nerve growth factor, and other chemicals that are necessary to repair the body.
c. Nonsteroidal anti-inflammatory drugs decrease pain by reducing the release of chemicals from damaged tissue.

Question 36

Itch, Exists in two forms:

Answer 36

a. In response to tissue damage, due to release of histamine.
b. In response to contact with certain plants.

Question 37

Itch is useful because:

Answer 37

• it directs you to scratch the itchy area and remove whatever is irritating your skin.
• Vigorous scratching produces mild pain, and pain inhibits itch. Opiates reduce pain and increase itch. The inhibitory relationship between pain and itch is evidence that itch is not a type of pain.

Question 38

Labeled-line principle:

Answer 38

Receptors of a sensory system that respond to a limited range of stimuli and send a direct line to the brain.

• Vertebrate sensory systems probably do not have any pure labeled-line codes.
• Taste and smell stimuli excite several kinds of neurons, and the meaning of a particular response by a particular neuron depends on the responses of other neurons.

Question 39

Across-fiber pattern principle:

Answer 39

Receptors of a sensory system respond to a wide range of stimuli and contribute to the perception of each of them.

Question 40

taste buds:

Answer 40

Taste results from the stimulation of taste buds.
- Taste differs from flavor, which is the combination of taste and smell. Taste and smell axons converge into many of the same cells in an area called the endopiriform cortex.

Question 41

papillae:

Answer 41

Mammalian taste receptors are located in taste buds, which are located in papillae (structures on the surface of the tongue). A given papillae may contain from 0 to 10 taste buds and each taste bud contains about 50 receptor cells.

Question 42

Adaptation:

Answer 42

Decreased response to a stimulus as a result of recent exposure to it

Question 43

Cross-adaptation:

Answer 43

A reduced response to one taste because of exposure to another. There is little cross-adaptation in taste.

Question 44

Umami:

Answer 44

A taste associated with glutamate. Researchers have found a glutamate taste receptor responsible for this fifth type of taste.

Question 45

nucleus of the tractus solitarius (NTS):

Answer 45

Three cranial nerves project to the nucleus of the tractus solitarius (NTS) in the medulla.
- The NTS relays information to the pons, lateral hypothalamus, amygdala, thalamus, and two areas of the cerebral cortex (the insula is responsible for taste, and the somatosensory cortex is responsible for the sense of touch on the tongue).

Question 46

supertasters:

Answer 46

d. People who taste PTC as extremely bitter are supertasters and have the highest sensitivity to all tastes.
e. Supertasters have the largest number of fungiform papillae (the type of papillae near the tip of the tongue).

Question 47

Phenythiocarbamide (PTC):

Answer 47

is a chemical whose taste is controlled by a single dominant gene. Some people hardly taste PTC, others taste it as bitter, and some taste it as extremely bitter.
- People who are insensitive to the taste of PTC are less sensitive to other tastes as well.

Question 48

Olfaction:

Answer 48

The sense of smell; the detection and recognition of chemicals that come in contact with membranes inside the nose.

Question 49

Olfactory cells:

Answer 49

Neurons that line the olfactory epithelium and are responsible for smell. In mammals, each olfactory cell has cilia (threadlike dendrites) where receptor sites are located.

• Olfactory receptors
• It is estimated that humans have hundreds of different types of olfactory receptor proteins. Rats and mice are believed to have a thousand types.
• In contrast to receptors for vision or hearing, olfactory receptors survive for just over one month and then are replaced by new cells that have the same odor sensitivities as the original cells.

Question 50

Individual Differences in Olfaction:

Answer 50

a. On average, women detect odors more readily than men, and the brain’s responses to odors are stronger in women.
b. Young adult women exposed repeatedly to a faint odor will gradually become more sensitive to the odor.
- This ability is not found in males, girls before puberty, or women after menopause.

Question 51

vomeronasal organ (VNO):

Answer 51

A set of receptors located near, but separate from, the olfactory receptors.

• The receptors in the VNO are specialized to respond only to pheromones. Each VNO receptor responds to just one pheromone and does not show adaptation after continued exposure.
• Unlike most mammals, the VNO is small in adult humans. Moreover, no receptors have been found in the human VNO.

Question 52

Pheromones:

Answer 52

Chemicals released by an animal that affect the behavior of other members of the same species, especially sexually.

6. Humans do respond to pheromones and have at least one type of pheromone receptor located in the olfactory mucosa.
7. Pheromones play a role in human sexual behavior similar to that in other mammals. Pheromones can synchronize the menstrual cycles of women who spend a lot of time together and enhance the regularity of the menstrual cycle of a woman who is in an intimate relationship with a man.

Question 53

Synesthesia:

Answer 53

is the experience some people have in which stimulation of one sense evokes a perception of that sense and another one also.

a. Someone might perceive the letter J as green or say that each taste feels like a particular shape on the tongue.
2. One hypothesis is that axons from one cortical area branch into another cortical area.