Deck 7: Sensory Physiology

Question 1

Which of these is one reason you can distinguish between a needle prick on the foot and an ice cube on the wrist?

A) The ice cube stimulates a different class of receptors than the needle prick, even though both signals go to exactly the same location in the brain.
B) The action potentials from the needle prick are inherently different from the impulse generated by the ice cube.
C) The region of the brain to which one receptor pathway leads is different from the region to which the other pathway leads.
D) The needle prick generates a stronger action potential in any one neuron than an ice cube does.
E) The needle prick generates a higher frequency of action potentials than the ice cube does.

Answer 1

C

Question 2

Accommodation for near vision requires:

A) flattening of the lens.
B) contraction of the ciliary muscles.
C) activation of the sympathetic nervous system.
D) increased rounding of the cornea.
E) dilation of the pupil.

Answer 2

B

Question 3

A stimulus to which afferent neurons X, Y, and Z are sensitive is applied in the middle of Y's receptive field. The same stimulus simultaneously activates receptors on the periphery of the receptive fields of X and Z. Which of the following is likely to be true?

A) The receptor potential in neurons X and Z will be more depolarized than in neuron Y.
B) It won't be possible to discriminate which neuron's receptive field was stimulated at its center.
C) The frequency of action potentials in the afferent pathway from neuron Y will be increased by excitatory interneurons projecting from the afferent pathways from neurons X and Z.
D) The frequency of action potentials in neuron Y will be greater than that in neurons X and Z.
E) The receptor potentials in all three neurons will achieve the same, average value.

Answer 3

D

Question 4

Which is TRUE regarding the ascending pathways in the sensory system?

A) Specific pathways for auditory stimuli project primarily to the frontal lobes of the cerebral cortex.
B) Specific pathways for all sensory information synapse in the somatosensory cortex.
C) Specific pathways for olfaction synapse in the limbic system.
D) Specific pathways for visual stimuli project primarily to the frontal lobes of the cerebral cortex.
E) Specific pathways for pain project primarily to the occipital lobes of the cerebral cortex.

Question 5

During normal viewing of a distant object, the:

A) firing of parasympathetic nerves to ciliary muscles increases.
B) zonular fibers are slackened.
C) lens flattens.
D) light rays striking the eyes are diverged by the cornea.
E) ciliary muscles are contracted.

Question 6

Which best describes lateral inhibition in the somatic sensory system?

A) The frequency of action potentials along pathways from the site of a stimulus is increased by lateral inhibition.
B) The precision of locating a stimulus is increased by inhibiting signaling along nearby, parallel pathways.
C) The precision of locating a stimulus is enhanced by increasing the frequency of action potentials in nearby, parallel pathways.
D) Stimuli of one particular modality in a region of the body block transmission of action potentials coding for other modalities generated in the same region of the body.
E) Lateral inhibition reduces the contrast between the frequency of action potentials generated at the center of a stimulus and the frequency of action potentials in surrounding pathways.

Question 7

A sensory unit is defined as

A) all of the sensory receptors in a given area of the body that respond to the same stimulus.
B) a single receptor ending and its afferent nerve fiber.
C) a single afferent neuron and all its receptor endings.
D) an afferent neuron and its postsynaptic interneurons.
E) a reflex composed of an afferent neuron, an interneuron, and an efferent neuron.

Question 8

Which of the following statements regarding the determination of stimulus intensity is true?

A) Stronger intensity stimuli cause rapid adaptation, while weaker stimuli cause slower adaptation.
B) The amplitude of action potentials increases with increasing stimulus intensity.
C) The duration of receptor potentials decreases with increasing stimulus intensity.
D) The frequency of action potentials increases with increasing stimulus intensity.
E) The only means of detecting intensity changes is through recruitment of greater numbers of sensory units.

Question 9

Which of the following is most important for the determination of stimulus type?

A) the relative sensitivity of different receptors to different stimulus energies
B) the presence of polymodal neurons in the sensory pathway
C) the intensity of a stimulus
D) the location on the body where a stimulus is applied
E) propagation of a signal along a nonspecific ascending pathway

Question 10

Which is TRUE about receptor potentials?

A) They are action potentials.
B) They always trigger action potentials.
C) They vary in magnitude with stimulus strength.
D) They propagate without decrement.
E) They generally occur at the axon hillock of afferent neurons.

Question 11

Which is an accurate description of the cortical association areas?

A) They are all found in the parietal lobe of the cerebral cortex.
B) They integrate multiple types of sensory information and are responsible for complex processing of sensory information.
C) They are the cortical locations where primary sensory information first arrives from specific ascending pathways.
D) They are found deep in the cerebrum, surrounding the thalamus.
E) Their main input is sensory information arriving along neurons that project directly from the thalamus.

Question 12

Polymodal neurons are:

A) afferent neurons.
B) interneurons that receive synaptic input from different kinds of sensory units.
C) part of specific ascending sensory pathways.
D) interneurons that receive synaptic input from only one type of sensory unit.
E) efferent neurons.

Question 13

Which of the following would NOT be categorized as a "somatic" sensation?

A) pressure
B) cold and warmth
C) sound
D) proprioception
E) kinesthesia

Question 14

Which of the following statements regarding the precision of locating a somatic stimulus is FALSE?

A) The precision is greater in areas of the body that have small, overlapping receptive fields than in areas with large, nonoverlapping receptive fields.
B) The precision is greater in the lips and fingers than on the back.
C) The precision is greater for the skin than for the internal organs.
D) Lateral inhibition of parallel afferent pathways increases the precision of locating a stimulus.
E) Convergence of afferent neurons onto common ascending pathways increases acuity.

Question 15

Which of the following statements regarding sensory systems is correct?

A) All sensory information that reaches the brain can be experienced as a conscious sensation.
B) Sensory information that leads to conscious awareness of the stimulus is called transduction.
C) The term "sensory unit" refers to a group of receptors that receive a particular stimulus and the afferent neuron associated with those receptors.
D) The term "adequate stimulus" means that a stimulus is strong enough to be detected.
E) Some sensory receptors are modifications of the peripheral endings of efferent neurons.

Question 16

Which best describes the process of "adaptation" in sensory receptors?

A) Information from sensory receptors reaches the cerebral cortex and the person becomes aware of it.
B) Conversion of the energy of a stimulus into a pattern of electrical activity.
C) Persistence of the sensation of a limb even after it has been severed from the body.
D) A decrease in receptor sensitivity despite continuation of a stimulus.
E) A depolarization of receptive membrane that increase in magnitude as the stimulus intensity increases.

Question 17

Which of the following statements regarding sensory pathways is correct?

A) All somatic sensory information that reaches the cerebral cortex is first processed in the thalamus.
B) Somatic sensory information from the left side of the body projects to the left side of the somatosensory cortex.
C) All somatic sensory information travels together in a single tract in the spinal cord.
D) Ascending pathways in the anterolateral column of the spinal cord carry information about fine touch discrimination.
E) Ascending pathways in the dorsal column of the spinal cord carry information about pain from the back muscles.

Question 18

Which of the following statements regarding pain pathways is FALSE?

A) Substance P is an important neurotransmitter in specific pain pathways.
B) Transmission of information in pain pathways may be inhibited by activation of neurons that synthesize opiate neurotransmitters.
C) Synaptic activity in afferent neurons associated with pain receptors can be inhibited by axon-axon synapses with neurons from descending pathways.
D) Afferents neurons that detect painful stimuli in the skin can converge onto common ascending pathways with neurons that detect painful stimuli in internal organs.
E) Substance P is released by neurons descending from the brain, and it inhibits activation of ascending pain pathways.

Question 19

Which of the following symptoms would a patient with a lesion (injury) that destroyed the right side of the spinal cord in the region of the upper back be most likely to experience?

A) loss of both pressure sense and pain in the right foot
B) loss of both pressure sense and pain in the left foot
C) loss of pressure sense in the right foot and pain in the left foot
D) loss of pressure sense in the left foot and pain in the right foot

Question 20

What is the best definition of the "receptive field" of an afferent neuron?

A) The number of interneurons with which the central process of the afferent neuron makes synaptic contact via divergence.
B) The type of stimulus energy to which the afferent neuron is most sensitive.
C) All of the interneuron cell bodies and dendrites onto which the afferent neuron synapses.
D) The area of the cerebral cortex in which information from that afferent neuron is initially received.
E) The area of the body that, when stimulated, leads to activity in that particular afferent neuron.

Question 21

Which of the following statements regarding hearing is TRUE?

A) The pitch of sounds is conveyed by the amplitude of the vibration of the oval window.
B) Low-pitched tones selectively cause vibration of the basilar membrane at a point closer to the oval window than high-pitched tones do.
C) Sound is amplified as it is conducted from the oval window to the tympanic membrane.
D) The loudness of a sound is conveyed by the frequency of action potentials generated in the cochlear nerve.

Question 22

The membrane potential of rod and cone cells is around:

A) -70 mV in the dark, and the cells depolarize in the light.
B) -70 mV in the dark, and the cells hyperpolarize in the light.
C) -35 mV in the dark, and the cells hyperpolarize in the light.
D) -35 mV in the dark, and the cells depolarize in the light.

Question 23

Vitamin A plays a critical role in night vision because:

A) it is required for the synthesis of the retinal portion of rhodopsin.
B) it is transformed into the opsins found in cone cells.
C) it acts a coenzyme in the reaction that degrades cGMP within rod cells.
D) it catalyzes the mitotic generation of light-reflecting epithelial cells, which support widely dispersed rod receptors.
E) it is a key intermediate in the signal transduction pathway within cone cells that is activated by light.

Question 24

Which of the following is NOT a function of the tensor tympani and stapedius muscles?

A) protection of the inner ear against continuous loud sounds
B) protection of the delicate inner ear from sudden intermittent loud sounds
C) reflexive contraction when vocalizing to reduce the loudness of your own voice
D) optimization of the state of the inner ear for hearing over certain frequency ranges

Question 25

Which of the following statements related to the "ON pathway" of the visual system is correct?

A) Bipolar cells fire action potentials only when bright light strikes the photoreceptors linked to them.
B) Bipolar cells spontaneously depolarize in the absence of input from photoreceptor cells.
C) Bipolar cells hyperpolarize in the absence of input from photoreceptor cells.
D) Glutamate receptors on bipolar cells are excitatory.
E) Only cones are associated with bipolar cells of the "ON pathway," rods are not.

Question 26

Which of these occurs when light strikes photoreceptors?

A) The chromophore retinal undergoes a change of shape.
B) There is an increase in neurotransmitter release from photoreceptor cells.
C) The photoreceptor cell membrane becomes depolarized.
D) The concentration of cyclic GMP inside cells increases.
E) The photoreceptor cells are stimulated and fire action potentials.

Question 27

Which of these is most responsible for "light adaptation"--the process by which we only gradually become able to see objects in a brightly lit place after being in the dark?

A) Cone receptors are very hyperpolarized in the dark, and they must be exposed to bright light for awhile before they will depolarize.
B) Rhodopsin is quickly inactivated in the presence of bright light so rods become unresponsive, and the higher-acuity cones then become the main detectors of vision.
C) Because rods are more sensitive to light than cones, they gradually become extremely activated in bright light.
D) Cones and rods are stimulated equally, leading to difficulties in interpreting the sensory inputs to the brain.
E) Rhodopsin is not activated by colored light, and the lack of stimulation causes rods to gradually depolarize when we are exposed to bright light.

Question 28

Which of the following statements about rods and cones in the retina is TRUE?

A) Cones enable us to see in dim light; rods provide color vision.
B) Rods and cones all have the same kind of opsin.
C) Cones are found in highest density in the fovea; rods are more prevalent near the edges of the retina.
D) Rods require brighter light to activate them than do cones.
E) Rods provide higher visual acuity than do cones.

Question 29

Which of the following statements with regard to vision is FALSE?

A) Photoreceptors are neurons.
B) There are two basic types of photoreceptors in the retina, rods, and cones.
C) There are normally four different photopigments in the retina.
D) There are four different chromophore molecules in the retina.
E) There are four different opsins in the retina.

Question 30

As the pitch of a sound gets higher, displacements of the basilar membrane:

A) occur closer to the oval window.
B) occur closer to the helicotrema.
C) occur uniformly throughout the membrane.
D) become greater in amplitude.
E) become smaller in amplitude.

Question 31

In ______ cells, infoldings of the external plasma membrane and proteins found there allow us to detect different colors of light.

A) bipolar
B) rod
C) ganglion
D) cone
E) pigment epithelial

Question 32

Which of the following statements regarding vision is FALSE?

A) The cornea refracts light rays more strongly than the lens.
B) Presbyopia is a condition in which the lens cannot accommodate adequately for near vision.
C) Myopia is a condition in which the lens focuses light from distant objects behind the retina.
D) Cataract is an increase in opacity (clouding) of the lens.
E) The image of an object that is focused on the retina is upside down relative to the object's actual position in space.

Question 33

The incus, malleus, and stapes of the middle ear

A) serve to keep the pressure on the two sides of the tympanic membrane equal.
B) are part of the vestibular apparatus.
C) are in direct contact with both the tympanic membrane and the round window.
D) serve to amplify the pressure of sound vibrations from the air in the outer ear to the fluid in the inner ear.
E) are found inside the cochlear duct.

Question 34

Each of the following statements regarding vision is true. Which statement best explains why we cannot see colors in dim light?

A) The human eye has three kinds of cone photoreceptors.
B) The lateral geniculate nucleus contains opponent color cells.
C) The human eye has only one kind of rod photoreceptor.
D) All photoreceptors contain the same chromophore.
E) Cone photoreceptors are concentrated in the fovea.

Question 35

A person whose lens focuses light from distant objects in front of (rather than on) the retina has a condition called:

A) presbyopia.
B) hyperopia.
C) myopia.
D) cataract.
E) glaucoma.

Question 36

A person struggling with a stressful exam question might experience difficulty focusing her eyes on the paper because:

A) she suddenly develops presbyopia.
B) activation of her parasympathetic nerves causes sudden contraction of her ciliary muscles.
C) activation of her sympathetic nerves causes sudden contraction of her ciliary muscles.
D) activation of her parasympathetic nerves inhibits contraction of her ciliary muscles.
E) activation of her sympathetic nerves inhibits contraction of her ciliary muscles.

Question 37

The receptors for hearing are found on the:

A) tympanic membrane.
B) basilar membrane.
C) stapes.
D) oval window.
E) scala vestibuli.

Question 38

Distinguishing the pitch of sounds is possible because:

A) different frequencies of sounds make the eardrum vibrate with different amplitudes.
B) different frequencies of sounds stimulate different regions of the basilar membrane in the cochlear duct.
C) different frequencies of sounds cause different kinds of action potentials in neurons in the auditory nerve.
D) different frequencies of sounds cause different frequencies of action potentials in neurons in the auditory nerve.
E) there are many different types of receptors for sound, each of which responds to a single frequency.

Question 39

The actual receptors for hearing are called:

A) baroreceptors.
B) nociceptors.
C) hair cells.
D) Pacinian corpuscles.
E) somatic receptors.

Question 40

In the visual pathway providing sensory action potentials to the brain, the first cells that are capable of initiating action potentials are:

A) cone cells.
B) rod cells.
C) lateral geniculate cells.
D) ganglion cells.
E) bipolar cells.

Question 41

Shaking your head "no" mainly activates hair cells in the:

A) cochlea.
B) utricle.
C) semicircular canals.
D) olfactory mucosa.
E) tectorial membrane.

Question 42

Sensory information is invested with emotional significance in association areas in the frontal lobes and limbic system.

Question 43

Perceptions are derived from higher-order processing of sensory information.

Question 44

The precision of locating a somatosensory stimulus is greater in areas of the body that have small, overlapping receptive fields than in areas with large, nonoverlapping fields.

Question 45

The density of receptors in a receptive field is usually greatest in the periphery of the field.

Question 46

Which of the following are classified as "mechanoreceptors"?

A) cone cells in the eye
B) taste buds on the tongue
C) hair cells in the olfactory mucosa
D) hair cells in the cochlea

Question 47

Rapidly adapting receptors are important for detecting the continued presence of a stimulus.

Question 48

A "sensation" is any sensory information that reaches the brain.

Question 49

"Somatosensory" refers to the part of the cerebral cortex that receives synaptic input from specific ascending pathways originating only with receptors for touch.

Question 50

Which is TRUE about information from the vestibular system?

A) It is conveyed in the form of action potentials in the optic nerve.
B) It is conveyed to nerves that control eye movements.
C) It does not reach the level of conscious perception.
D) It is primarily conveyed to the cortex of the occipital lobe of the brain.
E) It is interpreted as sound in the temporal lobes of the brain.

Question 51

The afferent pathways for pain differ from those for other somatic sensations in that they are highly influenced by repeated exposure and they are significantly modulated by descending neuronal pathways.

Question 52

The process by which sensory receptors change various forms of energy into electrical energy is called translation.

Question 53

The greater the magnitude of the receptor potential generated by a stimulus, the greater the amplitude of the action potentials the receptor potential induces.

Question 54

Which of the following statements regarding the vestibular system is TRUE?

A) Hair cells in the cochlea are involved in the detection of movement and position of the head.
B) The utricle and saccule are mainly responsible for detecting angular rotation of the head.
C) The vestibular apparatus is principally involved in our ability to detect and interpret sound.
D) Deflection of the basilar membrane by fluid moving within the semicircular canals allows us to detect rotational movement of the head.
E) Receptors in the utricle and saccule detect changes in the position of the head with respect to gravity.

Question 55

Where are receptors for the chemical senses located?

A) in the organ of Corti and saccule
B) in the cochlea and lateral geniculate nucleus
C) in the skin and tendons
D) in the tongue and nose
E) in the fovea and semicircular canals

Question 56

Which of the following correctly pairs a chemical with its associated taste modality?

A) poisonous alkaloids, sour
B) acids, bitter
C) sugars, salty
D) glutamate, umami
E) lipids, sweet

Question 57

Which is TRUE about olfactory receptors?

A) They can discriminate only four primary chemicals - sweet, sour, salty, and bitter.
B) When stimulated, their signaling pathway sends action potentials directly to the limbic system.
C) They are unable to detect odorants without activation of taste buds.
D) Only four different types of odorant receptor proteins are found in the plasma membrane of olfactory receptors.
E) They are found in the floor of the nasal cavity and on the upper surface of the hard palate, which separates the mouth from the nose.

Question 58

Information about the location of a given stimulus on or in the body is conveyed by the same mechanism that conveys information about stimulus intensity, namely action potential frequency.

Question 59

The phenomenon known as referred pain

A) is a perception of a false painful stimulus with no initiating stimulus; it is created in the mind.
B) is the projected perception of pain as a sensation being experienced at a site other than that of the actual injured or diseased tissue.
C) involves a descending pathway that blocks the release of substance P in the spinal cord.
D) is synonymous with the persistence of perceptions of painful stimuli long after the activity responsible for triggering them has ceased.

Question 60

In the somatosensory cortex, neuronal representation of body parts is proportional to the size of the body part.

Question 61

In the phenomenon of phantom limb, a person can perceive tingling, touch, pressure, warmth, itch, and other sensations in a body part that has been lost by amputation or accident.

Question 62

In both ON and OFF visual pathways, light stimulates the release of glutamate onto bipolar cells.

Question 63

The phenomenon of referred pain may occur because an ascending pathway for pain receives input from both visceral and somatic afferent fibers.

Question 64

Photoreceptor cells (rods and cones) are different from other sensory receptors in that they are the only type that is relatively depolarized at rest.

Question 65

Increased pressure in the eye caused by an accumulation of aqueous humor is called astigmatism.

Question 66

A sound with a frequency of 4000 Hz has a lower pitch than a sound with a frequency of 1000 Hz.

Question 67

Presbyopia is correctable using eyeglasses that converge light rays.

Question 68

A common neurotransmitter for afferent neurons carrying information about pain is prostaglandin.

Question 69

The optic nerves from each eye cross at the optic chiasm, so all visual information from the right eye is received by the left side of the brain.

Question 70

A tone caused by striking one of the lowest notes on a piano keyboard will cause vibration of the basilar membrane at a point closer to the helicotrema than to the oval window.

Question 71

The response of a bipolar cell, i.e., whether it acts to bring about an "ON pathway" or an "OFF pathway," depends on the amount of glutamate released by photoreceptor cells.

Question 72

The greatest concentration of cones is in the fovea centralis of the retina.

Question 73

Vitamin A deficiency can lead to blindness.

Question 74

The vibration of the tympanic membrane varies in frequency according to the pitch of the sound it receives.

Question 75

Axons of ganglion cells from the retina synapse in the medial geniculate nucleus of the thalamus on the way to the occipital lobes.

Question 76

The tympanic membrane separates an air-filled chamber from a fluid-filled chamber.

Question 77

Unlike information from the eyes, information from the ears bypasses the thalamus on its way to the cerebral cortex.

Question 78

Hair cells in the semicircular canals detect changes in the rate of angular motion of the head, while the same kinds of cells in the utricle and saccule detect changes in the head's rate of linear motion.

Question 79

One function of saccades is to prevent adaptation of photoreceptors to a visual image.

Question 80

The function of the tympanic membrane is to amplify sound waves on their way to the inner ear.