Question 1

The pathway leading to the perception of sound by mammals begins with the

Accepted Answer

A)  hair cells of the organ of Corti, which rests on the basilar membrane, coming in contact with the tectorial membrane.
B)  hair cells of the organ of Corti, which rests on the tympanic membrane, coming in contact with the tectorial membrane.
C)  hair cells of the organ of Corti, which rests on the tectorial membrane, coming in contact with the basilar membrane.
D)  hair cells of the organ of Corti coming in contact with the tectorial membrane as a result of fluid waves in the cochlea causing vibrations in the round window.
E)  hair cells on the tympanic membrane that stimulate the tectorial membrane neurons, leading to the auditory section of the brain.F) All of the above
G) B) and E)

Question 2

Mechanoreceptors that react to low frequency waves are part of the

Accepted Answer

A)  human sense of taste.
B)  pain receptors in birds.
C)  human sense of smell.
D)  lateral line systems in fish.
E)  eyes in arthropods.F) None of the above
G) B) and E)

Question 3

Calcium ions initiate sliding of filaments in skeletal muscles by

Accepted Answer

A)  breaking the actin-myosin cross-bridges.
B)  binding to the troponin complex, which then relocates tropomyosin.
C)  transmitting action potentials across the neuromuscular junction.
D)  spreading action potentials through the T tubules.
E)  reestablishing the resting membrane potential following an action potential.F) B) and D)
G) None of the above

Question 4

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) ?

Accepted Answer

A)  acetylcholine release
B)  conformational change in troponin
C)  depolarization of the muscle cell
D)  release of Ca²⁺ from the sarcoplasmic reticulum
E)  binding of actin to myosinF) D) and E)
G) A) and E)

Question 5

The olfactory bulbs are located

Accepted Answer

A)  in the nasal cavity.
B)  in the anterior pituitary gland.
C)  in the posterior pituitary gland.
D)  in the brain.
E)  in the brainstem.F) B) and E)
G) B) and C)

Question 6

Myasthenia gravis is a form of muscle paralysis in which

Accepted Answer

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)  the spinal cord is infected with a virus that attacks muscle stretch receptors.
E)  troponin molecules become unable to bind calcium ions.F) A) and E)
G) D) and E)

Question 7

The calcium ions released into the cytosol during excitation of skeletal muscle bind to

Accepted Answer

A)  troponin.
B)  tropomyosin.
C)  actin.
D)  myosin.
E)  transverse tubules.F) A) and E)
G) C) and E)

Question 8

Muscle cells are stimulated by neurotransmitters released from the synaptic terminals of

Accepted Answer

A)  T tubules.
B)  motor neuron axons.
C)  sensory neuron axons.
D)  motor neuron dendrites.
E)  sensory neuron dendrites.F) A) and D)
G) D) and E)

Question 9

A skeletal muscle with abnormally low levels of calcium ions would be impaired in

Accepted Answer

A)  ATP hydrolysis.
B)  the initiation of an action potential.
C)  maintaining its resting membrane potential.
D)  initiating contraction.
E)  its ability to sustain glycolysis.F) C) and E)
G) None of the above

Question 10

Tastes and smells are similar in that

Accepted Answer

A)  both types of stimuli are present in thousands of different chemicals.
B)  both types of stimuli must be dissolved in a body fluid before they can be detected.
C)  both types of stimuli are proteins (that is, molecules of very large size and high molecular weight) .
D)  both types of stimuli evoke action potentials in the cells to which they bind.
E)  any given stimulus for one system evokes a response from the other system.F) A) and E)
G) A) and D)

Question 11

Lateral inhibition via amacrine cells in the mammalian retina

Accepted Answer

A)  underlies habituation of vision.
B)  enhances visual contrast.
C)  prevents bleaching in bright light.
D)  is required for colour vision to occur.
E)  recycles neurotransmitter molecules.F) All of the above
G) C) and D)

Question 12

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

Accepted Answer

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)  The otoliths are unable to press on the hairs protruding into the gel in the inner ear.
E)  The utricle is damaged.F) B) and E)
G) A) and C)

Question 13

The cellular membrane across which ion flow varies during auditory transduction is the

Accepted Answer

A)  tectorial membrane.
B)  tympanic membrane.
C)  round-window membrane.
D)  hair cell membrane.
E)  basilar membrane.F) A) and B)
G) B) and C)

Question 14

The perceived pitch of a sound depends on

Accepted Answer

A)  which part of the tympanic membrane is being vibrated by sound waves.
B)  which part of the oval window produces waves in the cochlear fluid.
C)  which region of the basilar membrane was set in motion.
D)  whether or not the sound moves the incus, malleus, and stapes.
E)  the listener having had training in music.F) All of the above
G) B) and D)

Question 15

Sensory-transducing cells that fire both graded potentials and action potentials are found in

Accepted Answer

A)  vision.
B)  gustation.
C)  olfaction.
D)  audition.E) All of the above
F) B) and C)

Question 16

Sensory transduction of light/dark information in the vertebrate retina is accomplished by

Accepted Answer

A)  ganglion cells.
B)  amacrine cells.
C)  bipolar cells.
D)  horizontal cells.
E)  rods and cones.F) B) and E)
G) A) and C)

Question 17

The transduction of sound waves into action potentials takes place

Accepted Answer

A)  within the tectorial membrane as it is stimulated by the 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 becomes more permeable to sodium ions and depolarizes, initiating an action potential in a sensory neuron.
D)  as the basilar membrane vibrates at different frequencies in response to the varying volume of sounds.
E)  within the middle ear as the vibrations are amplified by the malleus, incus, and stapes.F) B) and E)
G) C) and D)

Question 18

What would happen to people exposed to a chemical warfare agent that blocked acetylcholine from binding to muscle receptors?

Accepted Answer

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.
E)  There would be no effect on the individual's muscles.F) C) and D)
G) A) and D)

Question 19

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

Accepted Answer

A)  thermoreceptors
B)  mechanoreceptors
C)  chemoreceptors
D)  electroreceptors
E)  neuroreceptorsF) B) and C)
G) D) and E)

Question 20

Corneal surgery is now routinely performed to change the shape of the cornea and improve vision.Why is this surgery beneficial?

Accepted Answer

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
E)  decreases the pressure in the eyeF) A) and B)
G) B) and E)

Exam 50: Sensory and Motor Mechanisms

What would happen to people exposed to a chemical warfare agent that blocked acetylcholine from binding to muscle receptors?

Correct AnswerverifiedShow Answer

The transduction of sound waves into action potentials takes place

Correct AnswerverifiedShow Answer

Muscle cells are stimulated by neurotransmitters released from the synaptic terminals of

Correct AnswerverifiedShow Answer

The calcium ions released into the cytosol during excitation of skeletal muscle bind to

Correct AnswerverifiedShow Answer

The olfactory bulbs are located

Correct AnswerverifiedShow Answer

Lateral inhibition via amacrine cells in the mammalian retina

Correct AnswerverifiedShow Answer

Corneal surgery is now routinely performed to change the shape of the cornea and improve vision.Why is this surgery beneficial?

Correct AnswerverifiedShow Answer

Tastes and smells are similar in that

Correct AnswerverifiedShow Answer

The cellular membrane across which ion flow varies during auditory transduction is the

Correct AnswerverifiedShow Answer

Sensory transduction of light/dark information in the vertebrate retina is accomplished by

Correct AnswerverifiedShow Answer

Calcium ions initiate sliding of filaments in skeletal muscles by

Correct AnswerverifiedShow Answer

The pathway leading to the perception of sound by mammals begins with the

Correct AnswerverifiedShow Answer

A skeletal muscle with abnormally low levels of calcium ions would be impaired in

Correct AnswerverifiedShow Answer

The perceived pitch of a sound depends on

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Mechanoreceptors that react to low frequency waves are part of the

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Sensory-transducing cells that fire both graded potentials and action potentials are found in

Correct AnswerverifiedShow Answer

Myasthenia gravis is a form of muscle paralysis in which

Correct AnswerverifiedShow Answer

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) ?

Correct AnswerverifiedShow Answer

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