Chapter 7

Question 1

Choose the true statement:
a. The modality of energy a given sensory receptor responds to in normal functioning is known as the “adequate stimulus” for that receptor.
b. Receptor potentials are “all-or-none”—that is, they have the same magnitude regardless of the strength of the stimulus.
c. When the frequency of action potentials along sensory neurons is constant as long as a stimulus continues, it is called “adaptation.”
d. When sensory units have large receptive fields, the acuity of perception is greater.
e. The “modality” refers to the intensity of a given stimulus.

Answer 1

a

Question 2

Using a single intracellular recording electrode, in what part of a sensory neuron could you simultaneously record both receptor potentials and action potentials?
a. in the cell body
b. at the node of Ranvier nearest the peripheral end
c. at the axon hillock where the axon meets the cell body
d. at the central axon terminals within the CNS
e. There is no single point where both can be measured.

Answer 2

b

Question 3

Which best describes “lateral inhibition” in sensory processing?
a. Presynaptic axo–axonal synapses reduce neurotransmitter release at excitatory synapses.
b. When a stimulus is maintained for a long time, action potentials from sensory receptors decrease in frequency with time.
c. Descending inputs from the brainstem inhibit afferent pain pathways in the spinal cord.
d. Inhibitory interneurons decrease action potentials from receptors at the periphery of a stimulated region.
e. Receptor potentials increase in magnitude with the strength of a stimulus.

Answer 3

d

Question 4

What region of the brain contains the primary visual cortex?
a. occipital lobe
b. frontal lobe
c. temporal lobe
d. somatosensory cortex
e. parietal lobe association area

Answer 4

a

Question 5

Which type of receptor does not encode a somatic sensation?
a. muscle-spindle stretch receptor
b. nociceptor
c. Pacinian corpuscle
d. thermoreceptor
e. cochlear hair cell

Answer 5

e

Question 6

Which best describes the vision of a person with uncorrected nearsightedness?
a. The eyeball is too long; far objects focus on the retina when the ciliary muscle contracts.
b. The eyeball is too long; near objects focus on the retina when the ciliary muscle is relaxed.
c. The eyeball is too long; near objects cannot be focused on the retina.
d. The eyeball is too short; far objects cannot be focused on the retina.
e. The eyeball is too short; near objects focus on the retina when the ciliary muscle is relaxed.

Answer 6

b

Question 7

If a patient suffers a stroke that destroys the optic tract on the right side of the brain, which of the following visual defects will result?
a. Complete blindness will result.
b. There will be no vision in the left eye, but vision will be normal in the right eye.
c. The patient will not perceive images of objects striking the left half of the retina in the left eye.
d. The patient will not perceive images of objects striking the right half of the retina in the right eye.
e. Neither eye will perceive objects in the right side of the patient’s field of view.

Answer 7

d

Question 8

Which correctly describes a step in auditory signal transduction?
a. Displacement of the basilar membrane with respect to the tectorial membrane stimulates stereocilia on the hair cells.
b. Pressure waves on the oval window cause vibrations of the malleus, which are transferred via the stapes to the round window.
c. Movement of the stapes causes oscillations in the tympanic membrane, which is in contact with the endolymph.
d. Oscillations of the stapes against the oval window set up pressure waves in the semicircular canals.
e. The malleus, incus, and stapes are found in the inner ear, within the cochlea.

Answer 8

a

Question 9

A standing subject looking over her left shoulder suddenly rotates her head to look over her right shoulder. How does the vestibular system detect this motion?
a. The utricle goes from a vertical to a horizontal position, and otoliths stimulate stereocilia.
b. Stretch receptors in neck muscles send action potentials to the vestibular apparatus, which relays them to the brain.
c. Fluid within the semicircular canals remains stationary, bending the cupula and stereocilia as the head rotates.
d. The movement causes endolymph in the cochlea to rotate from right to left, stimulating inner hair cells.
e. Counterrotation of the aqueous humor activates a nystagmus response.

Answer 9

c

Question 10

Which category of taste receptor cells does MSG (monosodium glutamate) most strongly stimulate?
a. salty
d. bitter
c. sweet
d. umami
e. sour

Answer 10

d

Question 11

Describe several mechanisms by which pain could theoretically be controlled medically or surgically.

Answer 11

NSAIDs, morphine, acupuncture, transcutaneous electrical nerve stimulation

Question 12

At what single site would a central nervous system injury interfere with the perception that heat is being applied to either side of the body?

Answer 12

thalamus

Question 12

At what two sites would central nervous system injuries interfere with the perception that heat is being applied to the right side of the body?

Answer 12

left somatosensory cortex, spinothalamic tract

Question 13

What would vision be like after a drug has destroyed all the cones in the retina?

Answer 13

loss of color vision, reduced visual acuity, impaired daytime vision

Question 14

Damage to what parts of the cerebral cortex could explain the following behaviors? (a) A person walks into a chair placed in her path. (b) The person does not walk into the chair, but she does not know what the chair can be used for

Answer 14

a: parietal lobe
b: temporal lobe

Question 15

How could the concept of referred pain potentially complicate the clinical assessment of the source of a patient’s somatic pain?

Answer 15

misdiagnosis, complications when treating, difficult to diagnose properly, misleading location of pain

Question 16

A key general principle of physiology is that homeostasis is essential for health and survival. How might sensory receptors responsible for detecting painful stimuli (nociceptors) contribute to homeostasis?

Answer 16

helps detect harmful stimuli (extreme temps, pressure, or chem changes), activation of protective reflexes (withdrawal reflex), triggers healing processes, regulation of bodily functions (helps regulate body’s response to injury or disease)

Question 17

sensory receptors, nerve pathways, and the brain areas that process sensory information

Answer 17

Sensory System

Question 18

conscious awareness of a stimulus

Answer 18

sensation

Question 19

understanding of the meaning of a sensation

Answer 19

perception

Question 20

at the peripheral ends of afferent neurons. In response to a stimulus, they generate graded potentials
called receptor potentials that can initiate action potentials, which travel into the CNS

Answer 20

sensory receptors

Question 21

Mechanoreceptors, Thermoreceptors, Photoreceptors, Chemoreceptors, and Nociceptor

Answer 21

sensory receptor major classes

Question 22

the type of energy to which a certain type of receptor responds best, specific, but also respond to other types of energy at high intensity

Answer 22

adequate stimulus

Question 23

the conversion of stimulus energy into a signal that conveys the relevant sensory information to the CNS

Answer 23

coding

Question 24

Information is conveyed by both the _____ ____ ____ ______ of the resulting electrical signals

Answer 24

frequency and the amplitude

Question 25

Important characteristics of a stimulus include the

Answer 25

type of input it represents, its intensity, and the location of the body it affects

Question 26

as stimulus modality, with specialized receptor for heat, cold, pressure, sound, and light

Answer 26

stimulus type

Question 27

Enables the localization of a stimulus site for some sensory systems

Answer 27

lateral inhibition

Question 28

Information from afferent neurons with receptors at the edge of a stimulus is strongly _______ compared to information from afferent neurons at the center

Answer 28

inhibited

Question 29

Enhances the contrast between the center and periphery of a stimulated region, thereby increasing the brain’s ability to ____ _ _____ _____

Answer 29

localize a sensory input

Question 30

All sensory signals are subject to extensive ______ before they reach higher levels of the CNS.

Answer 30

modification

Question 31

Modification can come from inhibition from collaterals from other ascending neurons, pathways descending from higher centers in the brain, by synapses on the axon terminals of the primary afferent neurons or indirectly via interneurons that affect other neurons in the sensory pathways.

Answer 31

Central Control of Afferent Information

Question 32

For example, in the pain pathways the afferent input is continuously inhibited to some extent. This allows either _______ __ ______

Answer 32

removing the inhibition or increasing the inhibition.

Question 33

are formed by chains of three or more neurons connected by synapses that form ascending pathways to the CNS

Answer 33

Afferent sensory pathways

Question 34

primary cortical receiving areas, association areas in the cerebral cortex for complex integration

Answer 34

Processing of afferent information

Question 35

Specific and nonspecific ascending pathways that

Answer 35

transmit the sensory information

Question 36

relies upon various cortical association areas to properly process sensory information.

Answer 36

primary somatosensory cortex

Question 37

processes the information in simple ways and serves basic sensory-related functions

Answer 37

region of association cortex closest to the primary sensory cortical area

Question 38

process the information with more complexity by contributing arousal, attention, memory, language, emotion, and motivation.

Answer 38

Regions farther from the primary sensory areas

Question 39

Factors that Affect Perception

Answer 39

Sensory receptor adaptation and afferent pathway processing emotions, personality, and experience lack of receptors for certain stimuli, such as radio waves damaged neural pathways drugs alter perception mental illness

Question 40

The structure of specific sensory receptor types allows them to best detect certain modalities and submodalities. General classes of receptor types include mechanoreceptors, thermoreceptors, photoreceptors, and chemoreceptors. The type of stimulus that specifically activates a given receptor is called that receptor’s adequate stimulus. Information in sensory pathways is organized such that initial cortical processing of the various modalities occurs in different parts of the brain.

Answer 40

modality

Question 41

Detecting stimulus duration occurs in two general ways, determined by a receptor property called adaptation. Some sensory receptors respond and generate receptor potentials the entire time that a stimulus is applied (slowly adapting, or tonic receptors), while others respond only briefly when a stimulus is first applied and sometimes again when the stimulus is removed (rapidly adapting, or phasic receptors

Answer 41

duration

Question 42

Sensory receptor potential amplitude tends to be graded according to the size of the stimulus applied, but action potential amplitude does not change with stimulus intensity. Rather, increasing stimulus intensity is encoded by the activation of increasing numbers of sensory neurons (recruitment) and by an increase in the frequency of action potentials propagated along sensory pathways.

Answer 42

intensity

Question 43

Stimuli of a given modality from a particular region of the body generally travel along dedicated, specific neural pathways to the brain, referred to as labeled lines. The acuity with which a stimulus can be localized depends on the size and density of receptive fields in each body region. A synaptic processing mechanism called lateral inhibition enhances localization as sensory signals travel through the CNS. Most specific ascending pathways synapse in the thalamus on the way to the cerebral cortex after crossing the midline, such that sensory information from the right side of the body is generally processed on the left side of the brain, and vice versa

Answer 43

location

Question 44

A consciously perceived stimulus is referred to as a sensation, and awareness of a stimulus combined with understanding of its meaning is called perception. This higher processing of sensory information occurs in association areas of the cerebral cortex

Answer 44

sensation and perception

Question 45

Sensation from the skin, skeletal muscles, bones, tendons, and joints

Answer 45

somatic sensation

Question 46

initiates somatic sensations by a variety of sensor receptors collectively called

Answer 46

somatic receptors

Question 47

_____ of somatic receptors gives rise to the sensations

Answer 47

activation

Question 48

rapidly adapting mechanoreceptor, touch and pressure

Answer 48

meissner's corpuscle

Question 49

slowly adapting mechanoreceptor, touch and pressure

Answer 49

merkel's corpuscle

Question 50

slowly adapting, including nociceptors, itch receptors, thermoreceptors, and mechanoreceptors

Answer 50

free neuron ending

Question 51

rapidly adapting mechanoreceptor, vibration and deep pressure

Answer 51

Pacinian corpuscles

Question 52

slowly adapting mechanoreceptor, skin stretch

Answer 52

ruffini corpuscle

Question 53

sensation of pain that is experienced at a site other than the injured or diseased tissue.

Answer 53

referred pain

Question 54

an increased sensitivity to painful stimuli. The pain can last for hours after the original stimulus is gone. This type of pain response is common with severe burn injuries.

Answer 54

hyperalgesia

Question 55

selective suppression of pain without effects on consciousness or other sensations

Answer 55

analgesia

Question 56

We use many mechanisms to achieve pain relief

Answer 56

* Electrical stimulation of specific areas of the central nervous system * Pharmacological agents (NSAIDs) and morphine (opioids) * Release of morphine-like endogenous opioids from some of the neurons in the inhibitory pathways * Acupuncture * Transcutaneous electrical nerve stimulation (TENS)

Question 57

A somatic sensation with mechanisms distinct from pain signaling pathways Result from abnormal functioning of neurons within the CNS, also originate with the stimulation of sensory receptors in the skin

Answer 57

itch

Question 58

acute sensation

Answer 58

mosquito bite

Question 59

persistent sensation

Answer 59

inflammatory conditions of skin like eczema

Question 60

visual perception requires

Answer 60

an organ, neural pathways

Question 61

the eye, which focuses the visual image and responds to light

Answer 61

visual organ

Question 62

which interpret the signals and transform the visual image into a pattern of graded and action potentials

Answer 62

vision neural pathways

Question 63

- relaxed ciliary muscles, tension on zonular fibers, flattened lens - light rays from distant objects are nearly parallel

Answer 63

in focus, distant

Question 64

- related ciliary muscles - light rays from near objects diverge

Answer 64

out of focus

Question 65

- firing of parasympathetic nerves, contracted ciliary muscles, slackened zonular fibers, rounded lens - near object with accommodation

Answer 65

in focus, near

Question 66

Light signals are converted into action potentials through the interaction of photoreceptors with ______

Answer 66

bipolar cells and ganglion cells

Question 67

only undergo graded responses because they lack the voltage-gated channels that mediate action potentials in other types of neurons.

Answer 67

Photoreceptor and bipolar cells

Question 68

the first cells in the pathway where action potentials can be initiated

Answer 68

ganglion cells

Question 69

Glutamate binds to metabotropic receptors that cause enzymatic breakdown of cGMP, which hyperpolarizes the bipolar cells, preventing release of excitatory neurotransmitter onto their associated ganglion cells

Answer 69

on-pathway

Question 70

spontaneously depolarize in the absence of input, glutamate receptors are inhibitory, ganglion cells are not stimulated to fire action potentials

Answer 70

bipolar cells

Question 71

bipolar cells hyperpolarize in the absence of input; glutamate receptors are excitatory.

Answer 71

off-pathway

Question 72

red cones

Answer 72

L

Question 73

green cones

Answer 73

M

Question 74

blue cones

Answer 74

S

Question 75

attached to the outside of each eyeball control its movement and perform two basic movements ( fast and slow )

Answer 75

six skeletal muscles

Question 76

fast movements; small, jerking movements that rapidly bring the eye from one fixation point to another to allow a search of the visual field, also preventing adaptation, also occur during certain periods of sleep when dreaming occurs

Answer 76

saccades

Question 77

involved both in tracking visual objects as they move through the visual field and during compensation for movements of the head from the vestibular system

Answer 77

slow eye movements

Question 78

Opacity/clouding of the lens, due to accumulation of proteins in the lens tissue; common after 65

Answer 78

cataract

Question 79

Cells of retina are damaged due to increased pressure within the eye; caused by lack of drainage of aqueous humor; major cause of irreversible blindness

Answer 79

glaucoma

Question 80

Impairment of macula lutea results in loss of vision in the center of the visual field, increases with age, referred to as age-related macular degeneration (AMD)

Answer 80

muscular degeneration

Question 81

based on the physics of sound and the physiology of the external, middle, and inner ear, the nerves to the brain, and the brain regions involved in sensing and perceiving acoustic information

Answer 81

audition

Question 82

Vestibular Information and Pathway used to

Answer 82

* control eye muscles * maintain upright posture and balance * provide awareness of body position and acceleration as well as spatial information

Question 83

increase the surface area of taste receptor cells and contain integral membrane proteins that transduce the presence of a given chemical into a receptor potential.

Answer 83

microvilli

Question 84

divide and differentiate to continually replace taste receptor cells damaged in the occasionally harsh environment.

Answer 84

basal cells

Question 85

detected by sodium influx.

Answer 85

salt taste

Question 86

detected by hydrogen ions blockingK+ efflux.

Answer 86

sour taste

Question 87

detected by binding of glucose to G-protein-coupled receptors.

Answer 87

sweet taste

Question 88

activates G-protein mediated second-messenger pathways

Answer 88

bitter flavor

Question 89

receptor cells also depolarize via a G protein-coupled receptor mechanism

Answer 89

umami

Question 90

bipolar neurons that survive for only about two months, so they are constantly being replaced by new cells produced from stem cells in the olfactory epithelium

Answer 90

Olfactory receptor neurons

Question 91

dissolve in the mucus that covers the epithelium and then bind to specific odorant receptors on the cilia.

Answer 91

odaorant