Deck 50: Sensory and Motor Mechanisms

Question 1

Although some sharks close their eyes just before they bite, their bites are on target. Researchers have noted that sharks often misdirect their bites at metal objects and that they can find batteries buried under sand. This evidence suggests that sharks keep track of their prey during the split second before they bite in the same way that a ________.

A) rattlesnake finds a mouse in its burrow
B) male silkworm moth locates a mate
C) bat finds moths in the dark
D) platypus locates its prey in a muddy river

Answer 1

D

Question 2

Immediately after putting on a shirt, your skin might feel itchy. However, this perception soon fades due to ________.

A) sensory adaptation
B) accommodation
C) reduced motor unit recruitment
D) reduced receptor amplification

Answer 2

A

Question 3

A given photon of light may trigger an action potential with thousands of times more energy because the signal strength is amplified by ________.

A) the receptor
B) ion channels
C) a signal transduction pathway
D) triggering several receptors at once

Answer 3

C

Question 4

Dizziness is a perceived sensation that can occur when ________.

A) the hair cells in the cochlea move more than their normal limits
B) moving fluid in the semicircular canals encounters a stationary cupula
C) rods and cones provide information that does not correspond with information received by cochlear hair cells
D) the basilar membrane makes physical contact with the tectorial membrane

Question 5

A physiologist is studying the homeostatic control of blood pH. What type of receptor might be responsible for detecting changes in blood pH?

A) mechanoreceptors
B) electromagnetic receptors
C) photoreceptors
D) chemoreceptors

Question 6

Which type of receptor would you expect to be most abundant in the antennae of a moth?

A) thermoreceptors
B) mechanoreceptors
C) chemoreceptors
D) electroreceptors

Question 7

The conversion of a stimulus into an action potential by a receptor cell is called ________.

A) integration
B) transmission
C) transduction
D) amplification

Question 8

Artificial electrical stimulation of a human's menthol-sensitive neurons would likely produce the sensation of ________.

A) cold temperature
B) hot temperature
C) odor of pepper
D) deep pressure

Question 9

The correct sequence of sensory processing is ________.

A) sensory adaptation → stimulus reception → sensory transduction → sensory perception
B) stimulus reception → sensory transduction → sensory perception → sensory adaptation
C) sensory perception → stimulus reception → sensory transduction → sensory adaptation
D) stimulus reception → sensory perception → sensory adaptation → sensory transduction

Question 10

During an auditory transduction, ion flow varies across the ________.

A) tectorial membrane
B) round-window membrane
C) hair cell membrane
D) basilar membrane

Question 11

Use the figure to answer the following question.

The structure diagrammed in the figure is the ________.

A) neuromast
B) statocyst
C) ommatidium
D) olfactory bulb

Question 12

Statocysts contain cells that are ________.

A) mechanoreceptors used to detect orientation relative to gravity
B) chemoreceptors used in selecting migration routes
C) photoreceptors used in setting biological rhythms
D) thermoreceptors used in prey detection

Question 13

Artificial electrical stimulation of a human's capsaicin-sensitive neurons would likely produce the sensation of ________.

A) cold temperature
B) hot temperature
C) tactile stimulus
D) deep pressure

Question 14

Partial or complete loss of hearing (deafness) can be caused by damage to the ________.
I)axons of the neurons associated with each hair cell that carry information to the brain
II)hair cells (the sensory receptors) in the cochlea
III)tympanic membrane, or eardrum

A) only II
B) only III
C) only I and II
D) I, II, and III

Question 15

The round window ________.
I)dampens fluid vibrations
II)collects sound pressure waves
III)detects the frequency of sounds

A) only I
B) only II
C) only III
D) only II and III

Question 16

The structure of the mammalian middle ear is adapted to convert ________.

A) air pressure waves to fluid pressure waves
B) fluid pressure waves to air pressure waves
C) air pressure waves to nerve impulses
D) fluid pressure waves to nerve impulses

Question 17

Elephants hear sounds that are too low for humans to hear. This sensitivity is primarily due to the differences in the ________.

A) arrangement and shape of the ossicles
B) flexibility of the basilar membrane in the cochlea
C) size and flexibility of the tympanic membrane (eardrum)
D) size and shape of the outer ear

Question 18

The 11 pairs of appendages projecting from the rostral area of star-nosed moles are ________.

A) chemosensory structures
B) tactile structures
C) olfactory structures
D) gustatory structures

Question 19

A person able to hear only low-frequency sounds would probably have which of the following structural problems in the ear?

A) The tympanum is damaged because of chronic ear infections.
B) The basilar membrane is stiffened along its entire length.
C) The ear ossicles are abnormally thickened.
D) There is a loss of hair cell function in the area closest to the oval window.

Question 20

When the mammalian brain compares the actual temperature of the body to the preferred temperature of the body, which general component is being used?

A) sensor
B) effector
C) integrator
D) motor

Question 21

Sensory transduction of light in the vertebrate retina is accomplished by ________.

A) ganglion cells
B) amacrine cells
C) bipolar cells
D) rods and cones

Question 22

Umami perception would be stimulated by ________.

A) chocolate milk
B) a slice or roast beef
C) acidic orange juice
D) salt water

Question 23

In the odorant cells of mammals, specific odorants are detected by binding to ________.

A) G protein-coupled receptors.
B) ligand-gated ion channels
C) acetylcholine receptors
D) glutamate receptors

Question 24

Corneal surgery is now routinely performed to change the shape of the cornea and improve vision. This surgery is beneficial because it ________.

A) improves the circulation of nutrients to the eye
B) improves the focusing of light onto the retina
C) decreases the amount of light entering the eye
D) increases the sensitivity of the photoreceptors

Question 25

What structures would neurobiologists look for if they are interested in determining if an animal can see in color?

A) opsins
B) electroreceptors
C) pupil
D) lens

Question 26

Methyl jasmonate is a plant-derived compound that blocks mosquito carbon dioxide receptors. What would you expect to happen if you applied this compound to your skin and then exposed yourself to a swarm of mosquitos?

A) The mosquitos would be repelled and fly as far away as possible from you.
B) The mosquitos would lack an important piece of sensory information for finding a host, and so would be less likely to bite you.
C) You would be a more attractive host for the mosquitos.
D) There would be no difference in the behavior of the mosquitos; they rely on visual cues to find their hosts.

Question 27

Lateral inhibition via horizontal cells in the mammalian retina ________.

A) underlies habituation of vision
B) enhances visual contrast
C) prevents bleaching in bright light
D) recycles neurotransmitter molecules

Question 28

Hair cells in the vertebrate ear are responsible for transducing sound pressure waves. Ion channels in the hair cell membrane open when ________.

A) a chemical ligand binds to the ion channel
B) light is absorbed by a molecule in the membrane
C) the cell membrane reaches a threshold voltage
D) the membrane is distorted mechanically

Question 29

The blind spot in the human retina is the location that has the collected axons of ________.

A) ganglion cells
B) bipolar cells
C) primary visual cortex
D) lateral geniculate nuclei

Question 30

It can be very difficult to select an angle for sneaking up to a grasshopper to catch it because grasshoppers have ________.

A) excellent hearing for detecting predators
B) compound eyes with multiple ommatidia
C) eyes with multiple fovea
D) a camera-like eye with multiple fovea

Question 31

Tastes and smells are distinct kinds of environmental information where ________.

A) neural projections from taste receptors reach different parts of the brain than the neural projections from olfactory receptors
B) the single area of the cerebral cortex that receives smell and taste signals can distinguish tastes and smells by the pattern of action potentials received
C) tastant molecules are airborne, whereas odorant molecules are dissolved in fluids
D) distinguishing tastant molecules requires learning, whereas smell discrimination is an innate process

Question 32

How could you genetically modify an animal so that it would distinguish more shades of green?

A) Induce genes to produce a greater number of cone cells in the fovea.
B) Introduce genes for different opsins that respond in the green region of the spectrum.
C) Introduce genes to produce green fluid in the eyeball, because green fluids will not absorb green light.
D) Induce increased production of cGMP to increase opening of cGMP-gated sodium channels.

Question 33

Two students studying physiology taste a known "bitter" substance, and both report sensing bitterness. They then sample another substance. Student A reports sensing both a bitter taste and a salty taste, but student B reports only a salty taste. What is the most logical explanation?

A) Student A had an allergic reaction to the food, causing him to perceive the food as being bitter.
B) Student A has normal "bitter" taste buds; student B has defective "bitter" taste buds that result in lower sensitivity to bitterness.
C) Student A has a protein receptor capable of detecting a bitter molecule found in that substance, whereas student B lacks that particular protein receptor.
D) Student A has normal saliva, whereas student B's saliva is more alkaline than normal.

Question 34

Experiments with genetically altered mice showed that the mice would consume abnormally high amounts of bitter-tasting compounds in water after their ________.

A) hormone receptors for digestive hormones were reduced or eliminated, showing that bitter tastes are reinforced by digestive responses
B) salt-taste cells were altered to express receptors for bitter tastants, suggesting that animals have unregulated salt appetites
C) visual sense was reduced or eliminated, suggesting that mice learn visual cues about bitter tastes
D) sweet-taste cells were altered to express receptors for bitter tastants, suggesting that the sensation of taste depends only on which taste cell is stimulated

Question 35

Most of the chemosensory neurons arising in the nasal cavity have axonal projections that terminate in the ________.

A) gustatory complex
B) olfactory bulb
C) occipital lobe
D) posterior pituitary gland

Question 36

In a mammalian visual system, visual information is integrated at ________.
I)the lens
II)the retina
III)the optic nerve
IV)the visual cortex

A) I and II
B) only II
C) II, III, and IV
D) II and IV

Question 37

The umami receptor in the sense of taste detects ________.

A) glucose
B) potassium ions
C) hydrogen ions
D) monosodium glutamate

Question 38

Which of the following sensory receptors is correctly paired with its category?

A) hair cell-mechanoreceptor
B) muscle spindle-electromagnetic receptor
C) taste receptor-mechanoreceptor
D) rod-chemoreceptor

Question 39

Rods exposed to light will ________.

A) depolarize due to the opening of sodium channels
B) hyperpolarize due to the closing of sodium channels
C) depolarize due to the opening of potassium channels
D) hyperpolarize due to the closing of potassium channels

Question 40

Compared to viewing a distant object, a human viewing an object held within five centimeters of the eye requires a lens that ________.

A) has been flattened, as a result of contraction of the ciliary muscles
B) has been made more spherical, as a result of contraction of the ciliary muscles
C) has been flattened, as a result of relaxation of the ciliary muscles
D) has been made more spherical, as a result of relaxation of the ciliary muscles

Question 41

Use the following information to answer the question.
"Marine cone snails from the genus Conus are estimated to consist of up to 700 species. These predatory molluscs have devised an efficient venom apparatus that allows them to successfully capture polychaete worms, other molluscs, or in some cases fish as their primary food sources. ?. . . conotoxins from Australian species of Conus . . . have the capacity to inhibit specifically the nicotinic acetylcholine receptors in higher animals." (B. G. Livett, K. R. Gayler, and Z. Khalil. 2004. Drugs from the sea: Conopeptides as potential therapeutics. Current Medicinal Chemistry 11:1715-23.)
What is the adaptive value of this toxin?
I)It would cause muscle spasms in the prey.
II)It would result in paralysis of the skeletal muscle of the prey.
III)It would stimulate digestive tract smooth muscle to cause nausea and vomiting of the prey.

A) only I
B) only II
C) only III
D) only I and II

Question 42

Myasthenia gravis is a form of muscle paralysis in which ________.

A) motor neurons lose their myelination and the ability to rapidly fire action potentials
B) acetylcholine receptors are destroyed by an overactive immune system
C) ATP production becomes uncoupled from mitochondrial electron transport
D) troponin molecules become unable to bind calcium ions

Question 43

Use the following information to answer the question.
"Marine cone snails from the genus Conus are estimated to consist of up to 700 species. These predatory molluscs have devised an efficient venom apparatus that allows them to successfully capture polychaete worms, other molluscs, or in some cases fish as their primary food sources.? . . . conotoxins from Australian species of Conus . . . have the capacity to inhibit specifically the nicotinic acetylcholine receptors in higher animals." (B. G. Livett, K. R. Gayler, and Z. Khalil. 2004. Drugs from the sea: Conopeptides as potential therapeutics. Current Medicinal Chemistry 11:1715-23.)
This particular conotoxin inhibits acetylcholine receptors that are located ________.

A) along the motor neuron axon
B) on motor neuron dendrites
C) on the presynaptic membrane of the neuromuscular junction
D) on the postsynaptic membrane, on the muscle cell

Question 44

Most of the ATP supplies for a skeletal muscle undergoing one hour of sustained exercise come from ________.

A) creatine phosphate
B) glycolysis
C) substrate phosphorylation
D) oxidative phosphorylation

Question 45

A patient is hospitalized with muscle spasms caused by failure of back muscles to relax after contraction. Which of the following would be most likely to help?

A) Inject calcium into the muscle cell, because it is not being released from the sarcoplasmic reticulum.
B) Induce tropomyosin and troponin to bind to the myosin binding sites on actin.
C) Increase the amount of acetylcholine at the synapses between motor neurons and muscle cells.
D) Depolarize the motor neurons to send an action potential to the muscle cells.

Question 46

An endoskeleton is the primary body support for the ________.

A) annelids, including earthworms
B) insects, including beetles
C) cartilaginous fishes, including sharks
D) bivalves, including clams

Question 47

Action potentials in the heart move from one contractile cell to the next via ________.

A) chemical synapses using acetylcholine
B) chemical synapses using norepinephrine
C) intercalated disks
D) non-myelinated motor neurons

Question 48

Among these choices, the most energetically efficient locomotion per unit mass is likely ________.

A) running by a 50-gram rodent
B) running by a 40-kilogram ungulate
C) flying by a 100-gram bird
D) swimming by a 100-kilogram tuna (bony fish)

Question 49

The leg muscles of a sprinter would differ from a marathon runner in that ________.

A) per gram, the sprinter's muscles would have more mitochondria than the marathon runner's muscles
B) per gram, the marathon runner's muscles would contain more myoglobin than the sprinter's muscles
C) the marathon runner's muscles would have a greater rate of contraction than the sprinter's muscles
D) per gram, the sprinter's muscles would use more oxygen than the marathon runner's muscles

Question 50

Compared to oxidative skeletal muscle fibers, those classified as glycolytic typically have ________.

A) a higher concentration of myoglobin
B) a higher density of mitochondria
C) a smaller diameter
D) less resistance to fatigue

Question 51

The venom of cobras contains a mixture of substances that have a variety of physiological effects. One substance in the venom works by preventing acetylcholine from binding to muscle receptors. How does the venom affect the prey of the cobra?

A) Action potentials would be continuously generated, causing convulsive muscle contractions.
B) Muscle contractions would be prevented, causing paralysis.
C) Muscle contractions could still occur, but relaxation of the muscle would be impaired.
D) Action potentials would be continuously generated, causing convulsive muscle contractions; muscle contractions would then be prevented, causing paralysis.

Question 52

The motor unit in vertebrate skeletal muscle refers to ________.

A) one actin binding site and its myosin partner
B) one sarcomere and all of its actin and myosin filaments
C) one myofibril and all of its sarcomeres
D) one motor neuron and all of the muscle fibers on which it has synapses

Question 53

The contraction of skeletal muscles is based on ________.

A) myosin filaments coiling up to become shorter
B) actin and myosin filaments both coiling up to become shorter
C) actin cross-bridges binding to myosin and transitioning from a high-energy to a low-energy state
D) myosin cross-bridges binding to actin and transitioning from a high-energy to a low-energy state

Question 54

A skeletal muscle deprived of adequate ATP supplies will ________.

A) immediately relax
B) enter a state where actin and myosin are unable to separate
C) fire many more action potentials than usual and enter a state of "rigor"
D) sequester all free calcium ions into the sarcoplasmic reticulum

Question 55

The muscles of a recently deceased human can remain in a contracted state, termed rigor mortis, for several hours, due to the lack of ________.

A) ATP needed to break actin-myosin bonds
B) calcium ions needed to bind to troponin
C) oxygen supplies needed for myoglobin
D) sodium ions needed to fire action potentials

Question 56

Which of the following is the correct sequence that describes the excitation and contraction of a skeletal muscle fiber?
1) Tropomyosin shifts and unblocks the cross-bridge binding sites.
2) Calcium is released and binds to the troponin complex.
3) Transverse tubules depolarize the sarcoplasmic reticulum.
4) The thin filaments are ratcheted across the thick filaments by the heads of the myosin molecules using energy from ATP.
5) An action potential in a motor neuron causes the axon to release acetylcholine, which depolarizes the muscle cell membrane.

A) 1 → 2 → 3 → 4 → 5
B) 2 → 1 → 3 → 5 → 4
C) 2 → 3 → 4 → 1 → 5
D) 5 → 3 → 2 → 1 → 4

Question 57

A ball-and-socket joint connects ________.

A) the radius to the ulna
B) the radius to the humerus
C) the ulna to the humerus
D) the humerus to the scapula

Question 58

The hydrostatic skeleton of the earthworm allows it to move around in its environment by ________.

A) walking on its limbs
B) swimming with its setae
C) using peristaltic contractions of its circular and longitudinal muscles
D) alternating contractions and relaxations of its flagella

Question 59

Which of the following are present in high densities in both smooth and skeletal muscle cells?
I)cilia
II)mitochondria
III)nuclei
IV)intercalated disks

A) only I
B) only II
C) III and IV
D) I, II, and III

Question 60

When an action potential from a motor neuron arrives at the neuromuscular junction (NMJ), a series of events occurs that leads to muscle contraction. Which of the following events will occur last (that is, after all of the others listed below)?

A) acetylcholine (ACh) release
B) conformational change in troponin
C) depolarization of the muscle cell
D) release of Ca²⁺ from the sarcoplasmic reticulum

Question 61

Although some sharks close their eyes just before they bite, their bites are on target. Researchers have noted that sharks often misdirect their bites at metal objects and that they can find batteries buried under sand. This evidence suggests that sharks keep track of their prey during the split second before they bite in the same way that

A) a rattlesnake finds a mouse in its burrow.
B) an insect avoids being stepped on.
C) a star-nosed mole locates its prey in tunnels.
D) a platypus locates its prey in a muddy river.

Question 62

During the contraction of a vertebrate skeletal muscle fiber, calcium ions

A) break cross-bridges as a cofactor in hydrolysis of ATP.
B) bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed.
C) transmit action potentials from the motor neuron to the muscle fiber.
D) spread action potentials through the T tubules.

Question 63

Which of the following sensory receptors is incorrectly paired with its category?

A) hair cell-mechanoreceptor
B) snake pit organ-thermoreceptor
C) taste receptor-chemoreceptor
D) olfactory receptor-electromagnetic receptor

Question 64

Chitin is a major component of the ________.

A) skeleton of mammals
B) hydrostatic skeletons of earthworms
C) exoskeleton of insects
D) body hairs of mammals

Question 65

The middle ear converts

A) air pressure waves to fluid pressure waves.
B) air pressure waves to nerve impulses.
C) fluid pressure waves to nerve impulses.
D) pressure waves to hair cell movements.

Question 66

Which sensory distinction is not encoded by a difference in neuron identity?

A) white and red
B) red and green
C) loud and faint
D) salty and sweet

Question 67

The transduction of sound waves into action potentials occurs

A) in the tectorial membrane as it is stimulated by hair cells.
B) when hair cells are bent against the tectorial membrane, causing them to depolarize and release neurotransmitter that stimulates sensory neurons.
C) as the basilar membrane vibrates at different frequencies in response to the varying volume of sounds.
D) within the middle ear as the vibrations are amplified by the malleus, incus, and stapes.