Midterm 2 Testbank

Question 1

24. 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.

Answer 1

D. There are four different chromophore molecules in the retina.

Question 2

22. 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.

Answer 2

C. Myopia is a condition in which the lens focuses light from distant objects behind the retina.

Question 3

22. Regarding psychoactive drugs,
    A. they can be taken to relieve altered states of consciousness.
    B. they can be taken to experience altered states of consciousness.
    C. they may stimulate neuronal activity in the “reward” areas of the brain.
    D. both “they can be taken to experience altered states of consciousness” and “they may stimulate neuronal activity in the ‘reward’ areas of the brain” are correct.
    E. All of the choices are correct.

Answer 3

All correct.

Question 4

15. Which of the following statements regarding the brain areas that direct emotion is not true?
    A. The hypothalamus is the site of the conscious feeling of emotion.
    B. The hypothalamus integrates emotional behaviors.
    C. The limbic system delivers information about emotion from the cerebral cortex to the hypothalamus.
    D. The cerebral cortex is responsible for control over emotions.
    E. None of the choices are true.

Answer 4

A. The hypothalamus is the site of the conscious feeling of emotion.

Question 5

39. Conceptual aphasia is a result of damage to 
A. the mouth and vocal cords.
B. the cerebellum.
C. broca's area.
D. wernicke's area.
E. the primary visual cortex.

Answer 5

D. wernicke’s area.

Question 6

If you were to record your own EEG activity while concentrating very hard on this exam, the most prominent EEG pattern would be

Answer 6

B. beta rhythm.

Question 7

29. Which of the following statements about different kinds of skeletal-muscle fibers is TRUE?
    A. Slow-oxidative fibers have a greater abundance of glycogen than do fast-glycolytic fibers.
    B. Fast-glycolytic fibers have a greater abundance of myoglobin than do slow-oxidative fibers.
    C. A fast-glycolytic fiber can generate greater tension than a slow-oxidative fiber.
    D. Fast-glycolytic fibers and slow-oxidative fibers are innervated by alpha motor neurons of the same diameter.
    E. To generate ATP, fast-glycolytic fibers depend mainly on oxidative phosphorylation while slow-oxidative fibers depend mainly on glycolysis.

Answer 7

C. A fast-glycolytic fiber can generate greater tension than a slow-oxidative fiber.

Question 8

37. Damage to that part of the brain known as Wernicke’s area is likely to
    A. cause difficulty in recognizing faces.
    B. be associated with impairment of procedural memory.
    C. impair comprehension of language.
    D. impair one’s ability to speak.
    E. cause blindness.

Answer 8

C. impair comprehension of language.

Question 9

42. Which of the following statements regarding contraction in skeletal and smooth muscle is TRUE?
    A. In skeletal muscle, calcium initiates contraction by binding to troponin, while in smooth muscle calcium initiates contraction by binding directly to myosin.
    B. In skeletal muscle, calcium ions bind to a regulatory protein on thin filaments; in smooth muscle, calcium ions bind to a regulatory protein on thick filaments.
    C. In skeletal muscle, calcium initiates contraction by binding to myosin light-chain kinase, while in smooth muscle calcium initiates contraction by binding directly to tropomyosin.
    D. In skeletal muscle, calcium initiates contraction by binding to troponin, while in smooth muscle calcium initiates contraction by binding to calmodulin.
    E. All of the choices are true.

Answer 9

D. In skeletal muscle, calcium initiates contraction by binding to troponin, while in smooth muscle calcium initiates contraction by binding to calmodulin.

Question 10

7. During paradoxical sleep,
   A. brain neurotransmitter activity in the pathways regulating states of consciousness is similar to that in the awake state.
   B. brain oxygen consumption is lower than when awake.
   C. skeletal muscle tension is dramatically increased.
   D. the person is easily aroused.
   E. All of the choices occur.

Answer 10

A. brain neurotransmitter activity in the pathways regulating states of consciousness is similar to that in the awake state.

Question 11

16. 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.

Answer 11

A. All somatic sensory information that reaches the cerebral cortex is first processed in the thalamus.

Question 12

19. During an isometric twitch in a skeletal muscle:

Answer 12

C. sarcomeres do not significantly shorten.

Question 13

19. Schizophrenia is most strongly associated with excessive production of or sensitivity to 
A. dopamine.
B. acetylcholine.
C. norepinephrine.
D. enkephalin.
E. lithium carbonate.

Answer 13

Dopamine

Question 14

50. Which dietary supplement is most likely to contribute to greater skeletal muscle ATP availability in the first few seconds of skeletal muscle contraction?
    A. fatty acids
    B. sports drinks with electrolytes and mineral spirits
    C. sugar
    D. protein
    E. creatine

Answer 14

e. creatine

Question 15

45. 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.

Answer 15

B. When stimulated, their signaling pathway sends action potentials directly to the limbic system.

Question 16

1. Which best describes a “myofibril?”
   A. It is a single skeletal-muscle cell.
   B. It is a cylindrical cellular organelle composed of myofilaments.
   C. It is a hollow membranous structure that stores calcium.
   D. It is composed of a single type of protein and forms cross-bridges.
   E. It is a fibrous junction between a muscle cell and a tendon.

Answer 16

B. It is a cylindrical cellular organelle composed of myofilaments.

Question 17

33. Damage to which of the following brain structures is most likely to result in difficulty in being able to remember meeting new people? 
A. thalamus
B. hippocampus
C. hypothalamus
D. corpus callosum
E. broca's area

Answer 17

B. Hippocampus

Question 18

12. 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.

Answer 18

E. Convergence of afferent neurons onto common ascending pathways increases acuity.

Question 19

17. Regarding schizophrenia,
    A. It is a family of mental disorders that involves disturbances of thinking, perceiving and control of motor activity.
    B. Its symptoms can include paranoid delusions and hallucinations.
    C. It probably has a hereditary component.
    D. Both “it is a family of mental disorders that involves disturbances of thinking, perceiving and control of motor activity” and “its symptoms can include paranoid delusions and hallucinations” are correct.
    E. All of the choices are correct.

Answer 19

All correct

Question 20

51. Myasthenia gravis is a collection of muscle disorders that cause muscle fatigue and weakness. What is the major mechanism?
    A. overproduction of acetylcholinesterase
    B. autoimmune destruction of nicotinic acetylcholine receptors
    C. demyelination of axons in motor pathways
    D. autoimmune destruction of L-type Ca2+ channels.
    E. a tumor that overproduces acetylcholine

Answer 20

B. autoimmune destruction of nicotinic acetylcholine receptors

Question 21

8. 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.

Answer 21

B. They integrate multiple types of sensory information and are responsible for complex processing of sensory information.

Question 22

20. 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.

Answer 22

C. lens flattens.

Question 23

30. Fast-glycolytic muscle fibers differ from slow-oxidative fibers in that:

Answer 23

C. fast-oxidative fibers can generate greater maximal tension than slow-oxidative fibers.

Question 24

38. Which of the following statements is FALSE?
    A. Synaptic input onto skeletal muscle cells is always excitatory, whereas inputs to smooth muscle cells may be either excitatory or inhibitory.

Answer 24

C. Contractile activity of smooth-muscle cells does not normally require Ca2+.

Question 25

40. Which of the following statements regarding higher brain functions is true?
    A. A person with damage only to Broca’s area of the brain will understand spoken or written speech but will have difficulty speaking.
    B. A person with damage only to Wernicke’s area of the brain will have motor aphasia.
    C. A person with damage only to Wernicke’s area of the brain will lose the ability to recognize faces.
    D. Both “a person with damage only to Broca’s area of the brain will understand spoken or written speech but will have difficulty speaking” and “a person with damage only to Wernicke’s area of the brain will have motor aphasia” are true.
    E. Both “a person with damage only to Broca’s area of the brain will understand spoken or written speech but will have difficulty speaking” and “a person with damage only to Wernicke’s area of the brain will lose the ability to recognize faces” are true.

Answer 25

A. A person with damage only to Broca’s area of the brain will understand spoken or written speech but will have difficulty speaking.

Question 26

28. Compared to type I (slow oxidative) skeletal muscle fibers, how are type II b (fast-glycolytic) skeletal-muscle fibers different?

Answer 26

B. Type II b fibers fatigue more readily.

Question 27

6. 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.

Answer 27

C. Specific pathways for olfaction synapse in the limbic system.

Question 28

Selective attention is facilitated, enhanced and improved by way of the \_\_\_\_\_ of the brain stem, which acts as the origin point of neurons which project to the cerebral cortex and release \_\_\_\_\_\_\_\_ neurotransmitter(s).
A. pons, acetylcholine
B. basal nuclei, dopamine
C. hypothalamus, serotonin
D. locus coeruleus, norepinephrine
E. thalamus, melatonin

Answer 28

D. locus coeruleus, norepinephrine

Question 29

21. Bipolar disorders

Answer 29

E. both “involve both mania and depression” and “are an exaggeration of normal changes in mood” are correct.

Question 30

1. 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.

Answer 30

C. The term, “sensory unit,” refers to a group of receptors that receive a particular stimulus and the afferent neuron associated with those receptors.

Question 31

14. A laboratory rat has an electrode implanted in its brain. By pressing a metal bar in its cage, the animal can activate the electrode. Which of the following is most likely to be true?
    A. If the animal presses the bar repeatedly, then the electrode is probably in an area associated with appetitive motivation.
    B. If the animal presses the bar once, then never touches it again, then the electrode is probably in an area associated with aversive motivation.
    C. Such an experiment has no relevance to emotional states in humans or human behavior.
    D. Both if the animal presses the bar repeatedly, then the electrode is probably in an area associated with appetitive motivation and if the animal presses the bar once, then never touches it again, then the electrode is probably in an area associated with aversive motivation are correct.
    E. All of the choices are correct.

Answer 31

D. Both if the animal presses the bar repeatedly, then the electrode is probably in an area associated with appetitive motivation and if the animal presses the bar once, then never touches it again, then the electrode is probably in an area associated with aversive motivation are correct.

Question 32

19. 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 32

B. contraction of the ciliary muscles.

Question 33

This part of the brain is thought to control the various states of consciousness.
A. cerebral cortex
B. reticular activating system
C. thalamus
D. cerebellum
E. hippocampus

Answer 33

B. reticular activating system

Question 34

34. Which of the following is an example of declarative memory?
    A. recognition of a person’s face and matching a name to it
    B. remembering how to ride a bicycle
    C. being able to recall a phone number for only a short period of time
    D. being given a specific address and being able to recall it several days or weeks later
    E. responding to the sight, smell, taste, or thought of one’s favorite food with salivation and hunger pangs

Answer 34

A. recognition of a person’s face and matching a name to it

Question 35

40. Which of the following is not a function of the tensor tympani and stapedius muscles?

Answer 35

B. protection of the delicate inner ear from sudden intermittent loud sounds

Question 36

10. In sleep apnea
    A. a person with the disorder experiences symptoms of sleep deprivation.
    B. periodic bouts of respiratory failure are experienced throughout the night.
    C. slow-wave and REM sleep predominate in sleep cycling.
    D. seriously low blood O2 levels result.
    E. All of the choices are correct.

Answer 36

All correct

Question 37

1. An electroencephalogram

Answer 37

B. records the potential difference between two points on the scalp’s surface.

Question 38

42. Shaking your head "no" mainly activates hair cells in the: 
A. cochlea. 
B. utricle. 
C. semicircular canals. 
D. olfactory mucosa. 
E. tectorial membrane.

Answer 38

C. Semicircular canals.

Question 39

3. 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.
   c

Answer 39

C. a single afferent neuron and all its receptor endings.

Question 40

3. The alpha rhythm is the most prominent EEG pattern when an adult is

Answer 40

C. awake and relaxed with eyes open.

Question 41

36. In most people, all of the following functions are lateralized to the left hemisphere except
    A. arithmetic ability.
    B. the ability to read and write.
    C. the ability to speak.
    D. the ability to recognize faces and read maps.
    E. None of these choices; all of these functions are lateralized to the left hemisphere.

Answer 41

D. the ability to recognize faces and read maps.

Question 42

14. 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 42

D. The frequency of action potentials in neuron Y will be greater than that in neurons X and Z.

Question 43

40. Which is a TRUE statement about smooth muscle?
    A. Smooth muscle is striated.
    B. Smooth muscle does not have thick and thin filaments.
    C. Smooth muscle does not use troponin-tropomyosin to regulate cross-bridge activity.
    D. Changes in cytosolic calcium do not regulate cross-bridge activity in smooth muscle.
    E. The myosin in smooth muscle requires phosphorylation before it can bind to ATP.

Answer 43

D. Changes in cytosolic calcium do not regulate cross-bridge activity in smooth muscle.

Question 44

47. The prolonged electrical depolarization of cardiac muscle cells that occurs during contraction is due primarily to the persistent influx of what ion? 
A. sodium 
B. calcium 
C. nitrate 
D. chloride 
E. potassium

Answer 44

B. calcium

Question 45

27. The plasma membranes of rod and cone cells are:

Answer 45

C. depolarized in the dark and hyperpolarized in the light.

Question 46

23. The optimal length (Lo) of a skeletal muscle cell is:

Answer 46

A. the length at which the muscle can generate its maximum tetanic tension.

Question 47

46. Which of the following choices lists a correct sequence of events following the depolarization of transverse tubules in excitation-contraction coupling in cardiac muscle?

Answer 47

E. calcium ion influx through sarcolemma, calcium release into cytosol, actin and myosin attach, thin myofilaments slide toward the middle of sarcomeres

Question 48

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

Answer 48

D. ganglion cells.

Question 49

13. Regarding its role as a neurotransmitter in the CNS, norepinephrine

Answer 49

both “is secreted by brain stem neurons in response to sensory stimulation” and “is important for maintaining directed attention” are correct.

Question 50

35. The incus, malleus, and stapes of the middle ear

Answer 50

D. serve to amplify the pressure of sound vibrations from the air in the outer ear to the fluid in the inner ear.

Question 51

36. The actual receptors for hearing are called:

Answer 51

C. Hair cells.

Question 52

39. Which of these is a major difference between smooth muscle and skeletal muscle?
    A. Myosin is the main regulatory protein in smooth muscle.
    B. Myosin is the main regulatory protein in skeletal muscle.
    C. Skeletal muscle usually exhibits spontaneous activity, while smooth muscle cannot contract spontaneously.
    D. Only skeletal muscle requires increased calcium ion concentration in the cytosol for contraction.
    E. Only skeletal muscle has both actin and myosin.

Answer 52

A. Myosin is the main regulatory protein in smooth muscle.

Question 53

7. Which occurs FIRST as a result of ATP binding to myosin?
   A. cross-bridge heads are cocked into an “energized” state
   B. actin dissociates from from myosin
   C. Ca2+ is released from the sarcoplasmic reticulum
   D. actin binds to myosin
   E. cross-bridges rotate, sliding past the thin filament

Answer 53

B. actin dissociates from from myosin

Question 54

23. Regarding psychoactive drugs,

Answer 54

E. both “the phenomenon of ‘tolerance’ to and the symptoms of ‘withdrawal’ from a psychoactive drug can be explained by the positive feedback effect of the drug on the production of the endogenous neurotransmitter/neuromodulator for which the drug is an agonist” and “use of psychoactive drugs may result in physical dependence upon them” are correct.

Question 55

7. 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.

Answer 55

B. interneurons that receive synaptic input from different kinds of sensory units.

Question 56

8. Which of the following most accurately describes the state of consciousness known as REM sleep?
   A. EEG tracings show large amplitude, low frequency waves; subject has very low muscle tone; if awakened will usually report dreaming
   B. EEG tracings show low amplitude, high frequency activity; subject has normal muscle tone; if awakened will usually report dreaming
   C. EEG tracings show low amplitude, high frequency activity; subject has very low muscle tone; if awakened will usually report dreaming
   D. EEG tracings show low amplitude, high frequency activity; subject has normal muscle tone; if awakened will not usually report dreaming
   E. EEG tracings show large amplitude, low frequency waves; subject has normal muscle tone; if awakened will usually report dreaming

Answer 56

C. EEG tracings show low amplitude, high frequency activity; subject has very low muscle tone; if awakened will usually report dreaming

Question 57

12. What is the definition of a “motor unit?”

Answer 57

A. a single motor neuron plus all the muscle fibers it innervates

Question 58

29. 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

Answer 58

D. cone

Question 59

43. 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

Answer 59

D. Hair cells in the cochlea

Question 60

17. 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.

Answer 60

E. Substance P is released by neurons descending from the brain, and it inhibits activation of ascending pain pathways.

Question 61

15. Which of the following would NOT be categorized as a "somatic" sensation? 
A. pressure 
B. cold and warmth 
C. sound 
D. proprioception 
E. kinesthesia

Answer 61

C. sound

Question 62

5. 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.

Answer 62

D. A decrease in receptor sensitivity despite continuation of a stimulus.

Question 63

34. Which of the following statements regarding hearing is TRUE?
    A. The pitch of sounds is conveyed by the intensity 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. Conduction deafness is a result of damage to the hair cells of the inner ear.
    E. The loudness of a sound is conveyed by the frequency of action potentials generated in the cochlear nerve.

Answer 63

E. The loudness of a sound is conveyed by the frequency of action potentials generated in the cochlear nerve.

Question 64

41. Which is a TRUE statement about excitation-contraction coupling?
    A. In skeletal muscle cells, it requires the influx of extracellular calcium ion.
    B. In smooth muscle cells, it must be preceded by an action potential in the cell membrane.
    C. In all kinds of muscle it requires the entry of calcium from the extracellular fluid.
    D. Calcium-induced calcium-release plays a role in cardiac muscle cells, as well as in some smooth muscle cells.
    E. In skeletal muscle cells, EC coupling begins when an action potential propagates along the sarcoplasmic reticulum membrane.

Answer 64

D. Calcium-induced calcium-release plays a role in cardiac muscle cells, as well as in some smooth muscle cells.

Question 65

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.

Answer 65

B. different frequencies of sounds stimulate different regions of the basilar membrane in the cochlear duct.

Question 66

49. Which best describes a role of L-type Ca2+ channels in cardiac muscle cells?
    A. They function exactly the same in cardiac muscle cells as they do in skeletal muscle.
    B. They are directly responsible for making cardiac muscle fatigue resistant.
    C. They are responsible for preventing tetanic contractions.
    D. They cause the absolute refractory period to be very brief.
    E. They act as non-conducting voltage sensors that mediate excitation-contraction coupling.

Answer 66

C. They are responsible for preventing tetanic contractions.

Question 67

9. Rigor mortis is caused by:

Answer 67

D. lack of ATP.

Question 68

31. Which of the following is NOT a determinant of whole-muscle tension?
    A. the number of muscle fibers contracting
    B. the tension produced by each contracting fiber
    C. the numbers of motor units recruited
    D. the frequency of motor neuron stimulation
    E. the proportion of the muscle fibers within each motor unit that are contracting at any given time

Answer 68

E. the proportion of the muscle fibers within each motor unit that are contracting at any given time

Question 69

10. 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 69

C. The region of the brain to which one receptor pathway leads is different from the region to which the other pathway leads.

Question 70

4. 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.

Answer 70

E. The area of the body that, when stimulated, leads to activity in that particular afferent neuron.

Question 71

2. What protein is the principle component of skeletal muscle thick filaments? 
A. actin 
B. myosin 
C. troponin 
D. calmodulin 
E. tropomyosin

Answer 71

B. myosin

Question 72

4. Which of the following statements regarding contraction of a skeletal-muscle fiber is TRUE?
   A. Thick filaments shorten when muscle cells contract.
   B. Some contractions occur without cross-bridge activation.
   C. Contracting muscle fibers do not always shorten.
   D. Contraction does not always require the occurrence of an action potential.
   E. Contraction only occurs following summation of action potentials from many motor neurons.

Answer 72

C. Contracting muscle fibers do not always shorten.

Question 73

36. John is a sprinter who specializes in quick and powerful bursts of speed followed by periods of rest. Jim is a marathon runner who specializes in long, steady runs. Compared to John’s muscles, how are Jim’s most likely to differ?
    A. Jim’s muscles will have more glycogen stored in his type II b muscle fibers.
    B. Jim’s muscles will have more mitochondria in his type I and II a muscle fibers.
    C. Jim’s muscles will have less myoglobin in his type I muscle fibers.
    D. Jim’s type II b fibers will be larger in diameter.
    E. Jim will have a greater proportion of type II muscle fibers and a lower proportion of type I fibers than John.

Answer 73

B. Jim’s muscles will have more mitochondria in his type I and II a muscle fibers.

Question 74

17. Myasthenia gravis is an autoimmune disease in which the immune system gradually destroys the receptors for acetylcholine at the neuromuscular junction. Which of the following drugs might initially be useful in treating the symptoms of this disease?

Answer 74

C. Sarcomere length does not change.

Question 75

21. 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.

Answer 75

C. myopia.

Question 76

32. Which of the following statements regarding skeletal muscle is TRUE?
    A. Skeletal muscle fibers have pacemaker activity.
    B. Skeletal muscle fibers are joined together by gap junctions.
    C. A given skeletal muscle fiber will contract when excitatory nervous stimuli sufficiently exceed inhibitory nervous stimuli at the motor end plate
    D. A given skeletal muscle fiber will contract if excitatory synaptic inputs sufficiently exceed inhibitory synaptic inputs on the motor neuron that innervates that fiber and the motor neuron fires an action potential.
    E. Skeletal muscle contraction is inhibited by inhibitory motor neurons that synapse onto skeletal muscle fibers.

Answer 76

D. A given skeletal muscle fiber will contract if excitatory synaptic inputs sufficiently exceed inhibitory synaptic inputs on the motor neuron that innervates that fiber and the motor neuron fires an action potential.

Question 77

30. 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 as the coenzyme required to degrade scotopsin in brightly lit circumstances.
    D. it catalyzes the mitotic generation of light-reflecting epithelial cells which support widely dispersed rod receptors.
    E. it deactivates the photopigment-transducing chemical pathways within cone cells.

Answer 77

A. it is required for the synthesis of the retinal portion of rhodopsin.

Question 78

2. 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.

Answer 78

C. They vary in magnitude with stimulus strength.

Question 79

18. 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 neck be most likely to experience?

Answer 79

C. loss of pressure sense in the right foot and pain in the left foot

Question 80

48. Which membrane protein transport process plays an important role in terminating the contraction of cardiac muscle?
    A. Ca 2+-ATPase pumps move Ca2+ from the T-tubule back into the sarcoplasmic reticulum.
    B. Na+/K+-ATPase pumps move Na+ back into the cytosol and K+ back into the T-tubule lumen.
    C. Ca2+-ATPase pumps move Ca2+ from the cytosol back into the sarcoplasmic reticulum.
    D. Na+/Ca2+-exchangers move Na+ out of the cytosol in exchange for Ca2+ movement into the sarcoplasmic reticulum.
    E. Na+/K+-ATPase pumps move Na+ and K+ back out of the cell.

Answer 80

C. Ca2+-ATPase pumps move Ca2+ from the cytosol back into the sarcoplasmic reticulum.

Question 81

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

Answer 81

A. the relative sensitivity of different receptors to different stimulus energies

Question 82

About 3-5% of school-aged children are diagnosed with attention deficit hyperactivity disorder (ADHD). This neurobehavioral problem is anatomically linked, primarily, to which area of dysfunction in the brain?

Answer 82

E. both basal nuclei and prefrontal cerebral cortex

Question 83

16. How does the chemical curare affect skeletal muscle function?

Answer 83

D. It is a nicotinic acetylcholine antagonist that blocks synaptic transmission at the neuromuscular junction.

Question 84

regarding skeletal-muscle contraction?
A. Only one cross-bridge cycle can occur when the [Ca2+] is elevated in the cytosol; in order to undergo a second cycle, [Ca2+] must be sequestered in the sarcoplasmic reticulum and released again.
B. ATP hydrolysis products must be removed from myosin before it can bind to actin.
C. Binding of myosin to actin takes place when [Ca2+] increases in the cytosol.
D. A single twitch in skeletal muscle lasts the same length of time as the action potential that causes it.
E. The powerstroke of the cross-bridge cycle occurs simultaneously with ATP being hydrolyzed into ADP and Pi.

Answer 84

C. Binding of myosin to actin takes place when [Ca2+] increases in the cytosol.

Question 85

39. 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.

Answer 85

A. occur closer to the oval window.

Question 86

24. Which of the following best explains how the phenomenon of “tolerance” develops with use of psychoactive drugs over time?
    A. Psychoactive drugs can alter blood flow to the brain.
    B. Psychoactive drugs often produce euphoria.
    C. Psychoactive drugs can cross the blood-brain barrier.
    D. Psychoactive drugs can inhibit production of endogenous neurotransmitters.
    E. Psychoactive drugs can up-regulate receptors for endogenous neurotransmitters.

Answer 86

D. Psychoactive drugs can inhibit production of endogenous neurotransmitters.

Question 87

23. A person struggling with a stressful exam question might experience difficulty focusing her eyes because:

Answer 87

E. activation of her sympathetic nerves inhibits contraction of her ciliary muscles.

Question 88

12. Habituation to a stimulus

Answer 88

E. both “is a result of decreased neurotransmitter release secondary to decreased calcium influx at synaptic terminals” and “can be overcome by a stronger stimulus of the same type” are correct.

Question 89

Drugs that are used to treat depression increase the levels of this neurotransmitter in the brain.
A. glutamate
B. serotonin
C. GABA
D. acetylcholine
E. dopamine

Answer 89

B. serotonin

Question 90

47. 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

Answer 90

D. glutamate, umami.

Question 91

31. A person with bilateral damage to the hippocampus will probably

Answer 91

C. suffer impairment of consolidation of declarative memory.

Question 92

41. The most nearly correct sequence of activation of brain areas when one responds in writing to a verbal command is:
    A. primary auditory cortex; Wernicke’s area; Broca’s area; supplementary motor cortex; primary motor cortex.
    B. primary auditory cortex; Broca’s area; supplementary motor cortex; Wernicke’s area; primary motor cortex.
    C. primary auditory cortex; Broca’s area; Wernicke’s area; supplementary motor cortex; primary motor cortex.
    D. primary auditory cortex; Broca’s area; Wernicke’s area; primary motor cortex; supplementary motor cortex.
    E. primary auditory cortex; Wernicke’s area; Broca’s area; primary motor cortex; supplementary motor cortex.

Answer 92

A. primary auditory cortex; Wernicke’s area; Broca’s area; supplementary motor cortex; primary motor cortex.

Question 93

16. Damage to the septum of the limbic system causes a tame animal to become vicious, whereas destruction of the amygdala will make the same animal docile again. Which of the following statements may explain this result or correctly follow from it?

Answer 93

B. In a normal animal, the septum may inhibit the amygdala.

Question 94

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.

Answer 94

A. The chromophore retinal undergoes a change of shape.

Question 95

25. Symptoms of withdrawal when drug use is stopped
    A. may result from lower-than-normal secretion of neurotransmitter.
    B. are psychological, not physical.
    C. may be alleviated by taking a drug that interacts with the same receptor as the original drug.
    D. both “may result from lower-than-normal secretion of neurotransmitter” and “may be alleviated by taking a drug that interacts with the same receptor as the original drug” are correct.
    E. All of the choices are correct.

Answer 95

D. both “may result from lower-than-normal secretion of neurotransmitter” and “may be alleviated by taking a drug that interacts with the same receptor as the original drug” are correct.

Question 96

33. 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.

Answer 96

B. Bipolar cells spontaneously depolarize in the absence of input from photoreceptor cells.

Question 97

48. The phenomenon known as referred pain

Answer 97

C. is the projected perception of pain as a sensation being experienced at a site other than that of the actual injured or diseased tissue.

Question 98

9. Which of the descriptions is not descriptive of REM (Rapid Eye Movement) sleep?

Answer 98

C. oxygen consumption decreases by comparison to NREM sleep and in an alert wakeful state

Question 99

13. What is the function of the transverse tubules in a skeletal-muscle fiber?

Answer 99

C. They allow action potentials to propagate deep into the center of skeletal muscle cells.

Question 100

44. 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

Answer 100

D. in the tongue and nose

Question 101

33. Which of these would increase the tension generated in a skeletal muscle?
    A. increasing the frequency of firing in alpha motor neurons innervating the muscle
    B. stretching the muscle to very long lengths
    C. resting the muscle for several weeks
    D. switching off fast-glycolytic motor units and activating an equal number of slow-oxidative motor units
    E. increasing the amplitude of action potentials in the alpha motor neurons that innervate the muscle

Answer 101

A. increasing the frequency of firing in alpha motor neurons innervating the muscle

Question 102

18. Regarding schizophrenia,
    A. People with schizophrenia frequently have disorders of sensory awareness.
    B. Treatment of schizophrenia may result in symptoms of Parkinson’s disease.
    C. Lithium carbonate is the most common drug prescribed for schizophrenia.
    D. Both “people with schizophrenia frequently have disorders of sensory awareness” and “treatment of schizophrenia may result in symptoms of Parkinson’s disease” are correct.
    E. Both “treatment of schizophrenia may result in symptoms of Parkinson’s disease” and “lithium carbonate is the most common drug prescribed for schizophrenia” are correct.

Answer 102

D. Both “people with schizophrenia frequently have disorders of sensory awareness” and “treatment of schizophrenia may result in symptoms of Parkinson’s disease” are correct.

Question 103

of skeletal muscle causes

Answer 103

D. the myosin binding sites on actin to be covered by tropomyosin

Question 104

13. 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.

Answer 104

B. The precision of locating a stimulus is increased by inhibiting signaling along nearby, parallel pathways.

Question 105

22. How is the length of a skeletal muscle cell related to the force it can generate?

Answer 105

E. Skeletal muscle cells generate the most force when the contraction occurs at an intermediate length.

Question 106

38. Damage to that part of the brain known as Broca’s area is likely to

Answer 106

C. impair speech.

Question 107

8. Which best describes “rigor mortis?”

Answer 107

A. Lack of ATP following death causes cross-bridges to remain tightly bound to actin.

Question 108

14. An action potential in the motor end plate rapidly spreads to the interior regions of a muscle cell by means of the:

Answer 108

D. transverse tubules.

Question 109

32. Anterograde amnesia is associated with damage to all of the following structures of the brain, except

Answer 109

D. corpus callosum.

Question 110

3. During concentric isotonic contraction of a skeletal-muscle fiber, which of these occurs? 
A. sarcomeres lengthen 
B. A bands shorten 
C. I bands shorten 
D. A bands lengthen 
E. thin filaments shorten

Answer 110

C. I bands shorten

Question 111

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

Answer 111

E. Receptors in the utricle and saccule detect changes in the position of the head with respect to gravity.

Question 112

35. John is a sprinter who specializes in quick and powerful bursts of speed followed by periods of rest. Jim is a marathon runner who specializes in long, steady runs. Compared to Jim, John is likely to have:
    A. legs with a larger diameter.
    B. legs with a smaller diameter.
    C. hypertrophy of type I muscle fibers.
    D. a higher density of capillaries in his legs.
    E. lower concentrations of glycolytic enzymes in his leg muscles.

Answer 112

A. legs with a larger diameter.

Question 113

25. 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.

Answer 113

C. Cones are found in highest density in the fovea; rods are more prevalent near the edges of the retina.

Question 114

26. Of the following substances, which has the greatest potential to cause dependence if used regularly?

Answer 114

a. nicotine

Question 115

46. 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.

Answer 115

B. It is conveyed to nerves that control eye movements.

Question 116

24. In the first few seconds of skeletal muscle contraction, what is the main mechanism by which ATP is replenished?

Answer 116

A. Energy and phosphate are transferred from creatine phosphate to ADP.

Question 117

6. Binding of \_\_\_\_\_\_\_\_ to myosin permits cross-bridge \_\_\_\_\_\_\_\_\_\_\_\_\_ between actin and myosin in skeletal muscle cells. 
A. ATP; attachment
B. ATP; detachment
C. calcium; attachment
D. calcium; detachment
E. actin; detachment

Answer 117

B. ATP; detachment

Question 118

30. The transfer of working memory into long-term memory is
    A. called memory retrieval.
    B. inhibited by such hormones as ACTH, epinephrine and vasopressin.
    C. thought to be caused by a relatively nonspecific “fix” signal.
    D. both called memory retrieval and inhibited by such hormones as ACTH, epinephrine, and vasopressin.
    E. both inhibited by such hormones as ACTH, epinephrine and vasopressin, and thought to be caused by a relatively nonspecific “fix” signal.

Answer 118

E. both inhibited by such hormones as ACTH, epinephrine and vasopressin, and thought to be caused by a relatively nonspecific “fix” signal.

Question 119

11. 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.

Answer 119

D. The frequency of action potentials increases with increasing stimulus intensity.

Question 120

6. Which of the following is not descriptive of REM sleep?
   A. It is the period when dreaming occurs.
   B. It normally occurs only once per night, usually just before waking up.
   C. Postural muscles are virtually paralyzed during REM sleep.
   D. EEG waves that resemble the awake state can be recorded during REM sleep.
   E. Eyes move rapidly back and forth beneath closed lids.

Answer 120

B. It normally occurs only once per night, usually just before waking up.

Question 121

20. Which of the following statements regarding skeletal-muscle contraction is true?
    A. During a lengthening contraction, the tension exerted by the muscle exceeds the load on the muscle.
    B. In every isotonic muscle contraction, the length of the muscle remains constant.
    C. During every muscle contraction, muscle fibers change length.
    D. During every muscle contraction, tension is developed in the muscle.
    E. Cross-bridges cycle faster during isometric contractions than during isotonic contractions.

Answer 121

D. During every muscle contraction, tension is developed in the muscle.

Question 122

27. Which of the following statements regarding myosin in skeletal muscle is TRUE?
    A. Myosin cross-bridge heads contain two binding sites, one for actin and one for tropomyosin.
    B. Myosin is an ATPase.
    C. The rate of ATP hydrolysis by myosin is the same in all types of skeletal muscle.
    D. All of the myosin cross-bridge heads in a thick filament are oriented and rotate in the same direction.
    E. Troponin covers the binding site on myosin molecules until Ca2+ binds to troponin to remove it from its blocking position.

Answer 122

B. Myosin is an ATPase.

Question 123

34. Which of the following statements regarding whole-muscle contraction is TRUE?
    A. The order of recruitment of motor units in a muscle is such that the last units recruited are those that fatigue most readily.
    B. The order of recruitment of motor units in a muscle is such that the first units recruited generate the most tension
    C. Motor units whose motor neurons have large-diameter cell bodies are recruited first, while motor units with smaller-diameter motor neurons are only activated as the level of activation in the spinal cord increases.
    D. The order of motor unit recruitment is independent of the size of the alpha motor neuron that innervates them.
    E. Recruitment of one fast-glycolytic motor unit provides a smaller increment in whole-muscle tension than recruitment of one slow-oxidative motor unit.

Answer 123

A. The order of recruitment of motor units in a muscle is such that the last units recruited are those that fatigue most readily.

Question 124

26.

Why does breathing continue to be rapid and deep for a time after heavy exercise?

Answer 124

A. Extra oxygen is needed to eliminate lactic acid and restore muscle creatine phosphate and glucose concentration.

Question 125

37. The receptors for hearing are found on the:

Answer 125

B. basilar membrane.

Question 126

28. 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. There are six types of opponent color cells in the lateral geniculate nucleus.
    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.

Answer 126

C. The human eye has only one kind of rod photoreceptor.

Question 127

5. Which of the following statements about sleep is correct?
   A. Sleep typically occurs in stages in which a subject goes through progressively deeper stages of sleep and then awakens.
   B. Sleep typically occurs in cycles in which a subject will cycle through various stages of slow-wave sleep punctuated by paradoxical sleep several times during one bout of sleep.
   C. During REM sleep, blood pressure and breathing rate become elevated.
   D. Both “sleep typically occurs in stages in which a subject goes through progressively deeper stages of sleep and then awakens” and “during REM sleep, blood pressure and breathing rate become elevated” are correct.
   E. Both “sleep typically occurs in cycles in which a subject will cycle through various stages of slow-wave sleep punctuated by paradoxical sleep several times during one bout of sleep” and “during REM sleep, blood pressure and breathing rate become elevated” are correct.

Answer 127

E.

Question 128

35. When a person loses consciousness, working memory is interrupted and memories are abolished for all that happened for a variable period of time before the blow that caused unconsciousness. Why?
    A. The traumatic blow to the head caused a concussion through violent displacement of the brain in the skull.
    B. There was a deficiency of adequate blood flow to the brain.
    C. There was an interruption in the constant stream of neuron potentials to memory facilitation brain areas.
    D. Conflicting external interference prevents conversion of short-term to long-term memory.
    E. This is an area of neurological research which has not achieved any satisfying conclusions at the present time.

Answer 128

C. There was an interruption in the constant stream of neuron potentials to memory facilitation brain areas.

Question 129

5. In skeletal muscle cells, calcium initiates contraction by binding to: 
A. tropomyosin. 
B. actin. 
C. troponin. 
D. myosin. 
E. the thick filament.

Answer 129

C. troponin.

Question 130

31. 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?

Answer 130

C. Because rods are more sensitive to light than cones, they gradually become extremely activated in bright light.

Question 131

state, leading to spastic contractions of muscle.
d
17. Myasthenia gravis is an autoimmune disease in which the immune system gradually destroys the receptors for acetylcholine at the neuromuscular junction. Which of the following drugs might initially be useful in treating the symptoms of this disease?
A. a drug that inhibits acetylcholinesterase
B. a drug that inhibits release of acetylcholine
C. curare
D. atropine (a muscarinic acetylcholine receptor antagonist)
E. a nicotinic acetylcholine receptor antagonist
a
18. Which of these occurs during an isometric contraction of a skeletal muscle?
A. The I bands shorten and the A bands stay the same length.
B. The thick and thin filaments slide past each other.
C. Sarcomere length does not change.
D. The A bands shorten and the I bands stay the same length.
E. Cross-bridges lock onto actin, similar to what occurs in rigor mortis.
c
19. During an isometric twitch in a skeletal muscle:
A. tension generated by the muscle always exceeds the load on the muscle.
B. tetanus occurs.
C. sarcomeres do not significantly shorten.
D. the whole muscle shortens.
E. the load on the muscle is always greater than the tension generated.
c
20. Which of the following statements regarding skeletal-muscle contraction is true?
A. During a lengthening contraction, the tension exerted by the muscle exceeds the load on the muscle.
B. In every isotonic muscle contraction, the length of the muscle remains constant.
C. During every muscle contraction, muscle fibers change length.
D. During every muscle contraction, tension is developed in the muscle.
E. Cross-bridges cycle faster during isometric contractions than during isotonic contractions.
d
21. What is the best description of a tetanic contraction in a skeletal muscle cell?

Answer 131

B. Multiple action potentials in the motor neuron cause a sustained contraction.

Question 132

29. Unlike long-term memory, working memory
    A. has unlimited capacity.
    B. exists in the form of either graded or action potentials.
    C. can be disrupted by drugs, electroconvulsive shock or a blow to the head.
    D. Both “have unlimited capacity” and “exist in the form of either graded or action potentials” are correct.
    E. Both “exist in the form of either graded or action potentials” and “can be disrupted by drugs, electroconvulsive shock, or a blow to the head” are correct.

Answer 132

E. Both “exist in the form of either graded or action potentials” and “can be disrupted by drugs, electroconvulsive shock, or a blow to the head” are correct.
e

Question 133

It is believed that the rhythmic patterns of the EEG most likely originate from this structure in the brain.

Answer 133

B. thalamus

Question 134

15. Which of the following statements regarding the motor end plate of a skeletal-muscle fiber is TRUE?

Answer 134

C. Acetylcholinesterase in the end plate membrane catalyzes the breakdown of acetylcholine.

Question 135

45. Which of the following does NOT correctly describe cardiac muscle cells?
    A. They are arranged in layers surrounding hollow cavities in the heart.
    B. They are much shorter than skeletal muscle fibers, and generally have a single nucleus.
    C. Their membranes are depolarized initially by the influx of sodium ions.
    D. They depolarize prior to contraction.
    E. They can contract in the absence of external calcium.

Answer 135

E. They can contract in the absence of external calcium.

Question 136

25. When a muscle has been repeatedly contracting at a moderate intensity for an extended period of time (more than a few minutes), what is the primary source of ATP?

Answer 136

C. oxidative phosphorylation

Question 137

43. Which of the following is FALSE regarding single-unit smooth-muscle cells?
    A. They have an individual neuron innervating of each individual smooth-muscle cell.
    B. They have many gap junctions between cells.
    C. They may have pacemaker activity.
    D. They may respond to stretch by contracting.
    E. They exhibit tone.

Answer 137

A. They have an individual neuron innervating of each individual smooth-muscle cell.