Deck 30: Nervous and Sensory Systems

Question 1

A myelin sheath

A) stores sodium ions.
B) acts as an electrical conductor.
C) acts as an insulator.
D) contains action potentials.

Answer 1

C

Question 2

A reflex arc

A) has only sensory neurons and interneurons.
B) is composed of three interneurons.
C) has a sensory neuron,an interneuron,and a motor neuron.
D) has an interneuron between two motor neurons.

Answer 2

C

Question 3

Which of the following best describes the flow of signals in our nervous system?

A) from motor neurons to sensory neurons to interneurons
B) from sensory neurons to interneurons to motor neurons
C) from interneurons to sensory neurons to motor neurons
D) from sensory neurons to motor neurons to interneurons

Answer 3

B

Question 4

Although many people worry about their sodium intake from salty foods,it would be unwise to eliminate sodium from one's diet completely.Which of the following problems would occur if there were no sodium in the body?

A) The myelin sheath of the neurons would begin to break down.
B) Axons would be unable to create the action potential necessary for rapid signal movement.
C) The synapses between neurons and their adjacent cells would collapse.
D) The speed of the neuron's action potential would increase to a dangerously high level.

Question 5

Which of the following is an example of a reflex arc?

A) After reading all the possible answers to this question,you choose answer A.
B) The pupils of your eyes increase in diameter when you walk into a dark room.
C) A cell in your body releases insulin in response to the intake of food.
D) On a hot day,your body releases sweat.As the sweat evaporates,your body cools.

Question 6

The branched receiving ends of a nerve cell are called

A) dendrites.
B) axons.
C) neurons.
D) synapses.

Question 7

Action potentials move faster in myelinated nerve fibers because

A) sodium ions can leap from node to node.
B) dendrites do not need to connect directly to axons.
C) sodium ions can pass through myelin faster than they do across the plasma membrane of a neuron.
D) action potentials leap from node to node.

Question 8

How does the central nervous system recognize how important a particular stimulus is?

A) by the frequency at which the action potentials are created by the stimulus
B) by the overall strength of the action potential produced by the stimulus
C) by the number of neurotransmitters that reach the brain through the circulatory system
D) by the amount of hormone that the stimulus releases from endocrine glands

Question 9

Axons transmit information in the form of

A) resting potentials.
B) sodium channels.
C) action potentials.
D) myelin sheaths.

Question 10

Initially,when a neuron receives a stimulus,

A) sodium diffuses out of the neuron.
B) neurotransmitters are released from axon terminals.
C) sodium channels close.
D) sodium enters the neuron.

Question 11

Neurotransmitters carry a signal from a stimulated nerve cell to another nerve cell across a gap known as a

A) synaptic cleft.
B) target.
C) receptor.
D) cytokinin.

Question 12

Botulism is a type of paralysis (inability to move muscles)caused by a specific type of bacteria.The bacteria release a toxin that prevents the release of acetylcholine (a neurotransmitter)from the neurons that form synapses with muscle cells.Why might botulism toxin cause paralysis?

A) Without acetylcholine,action potentials never get to muscle cells because they cannot move from one node of Ranvier to the next.
B) Since acetylcholine is responsible for establishing the concentration gradient of sodium ions,action potentials cannot form in the neurons of individuals with botulism.
C) If acetylcholine is not released,action potentials that stimulate muscle contraction cannot be transmitted across the synaptic cleft to muscle cells.
D) In the absence of acetylcholine,sensory neurons are unable to communicate with motor neurons,so motor neurons never receive the signal to cause muscle contraction.

Question 13

An action potential travels in only one direction because

A) the nodes of Ranvier are open only at the site of the action potential.
B) only the sodium channels "downstream" are open.
C) only the sodium channels at the site of the action potential remain open.
D) sodium ions can move only between the nodes of Ranvier.

Question 14

If a stimulus is strong enough to reach a threshold level,

A) an action potential is shut down.
B) an action potential occurs.
C) sodium channels in the myelin open.
D) the resting potential is restored.

Question 15

At resting potential,the charge outside the neuron's plasma membrane is

A) positive because of the movement of myelin out of a neuron.
B) negative because of the sodium ions being pumped out of a neuron.
C) positive because sodium channels open in the axon but not in the cell body.
D) negative because sodium channels close in the dendrite but not in the axon.

Question 16

Which of the following statements about axons is FALSE?

A) Action potentials travel quickly in myelinated axons.
B) Axons transmit signals in two directions.
C) Axons are a long extension of a neuron.
D) Axons have a terminus that transmits signals to other cells.

Question 17

Which of the following is the pathway an action potential would travel in a neuron?

A) cell body to axon to dendrite
B) axon to dendrite to cell body
C) dendrite to axon to cell body
D) dendrite to cell body to axon

Question 18

The figure below illustrates how a neuron with a myelinated axon transmits signals.

What is happening in Region A of this figure?

A) An action potential is moving between two nodes of Ranvier.
B) Neurotransmitters are rapidly diffusing between two nodes of Ranvier.
C) An electric charge is moving rapidly between two nodes of Ranvier.
D) Myelin is carrying sodium ions between two nodes of Ranvier.

Question 19

A strong stimulus produces

A) stronger action potentials.
B) more action potentials.
C) both more and stronger action potentials.
D) more nodes of Ranvier.

Question 20

A person with vitamin B deficiency often exhibits a "slow" nervous system.For example,his or her knee-jerk reflex is much slower than normal.Which of the following might explain why this is the case?

A) The neurons of people with vitamin B deficiency have more sodium channels in the plasma membranes of their neurons than normal.
B) People with a vitamin B deficiency produce less myelin than normal people do.
C) Axons are slightly longer in a person with vitamin B deficiency,so the distance between transmitting and receiving cells is shorter.
D) People with vitamin B deficiencies produce weaker action potentials than normal people do.

Question 21

After a signal has been transmitted to a receiving cell,neurotransmitters are rapidly removed from the synaptic cleft because

A) if even one neurotransmitter escapes from the synaptic cleft,it will produce action potentials in other neurons.
B) if neurotransmitters are not removed,they will enter the receiving cell and stimulate action potentials in organelle membranes.
C) neurotransmitters that remain in the synaptic cleft continue to bind to receptors in the receiving cell,potentially initiating new action potentials.
D) making neurotransmitters from scratch is energetically expensive,so the cell must recycle them.

Question 22

The largest,most visible part of the human brain is the

A) hippocampus.
B) cerebrum.
C) hypothalamus.
D) thalamus.

Question 23

As you read this question,your eyes are moving to project the image of each word on your

A) pupil.
B) lens.
C) rods.
D) fovea.

Question 24

A drug that decreases your ability to taste and smell might inhibit the function of

A) photoreceptors.
B) thermoreceptors.
C) mechanoreceptors.
D) chemoreceptors.

Question 25

The human skin has numerous sensory receptors that take in information about our environment,and these receptors are concentrated in areas where detailed information on touch is needed.Which of the following body areas is likely to have the smallest number of sensory receptors?

A) fingertips
B) the face
C) buttocks
D) feet

Question 26

As you complete this exam,which part of the brain is helping you decide which answer is correct?

A) the cerebellum
B) the pons
C) the thalamus
D) the cerebral cortex

Question 27

Researchers have suggested a fifth taste in humans known as umami and attribute the taste to the compound glutamate.Which of the following would support the belief that umami is a real taste?

A) identifying a chemoreceptor in the nasal cavity that glutamate can bind to
B) the isolation of a sensory neuron that creates nerve impulses in response to pressure from glutamate
C) finding chemoreceptors in a taste bud that create nerve impulses in response to an interaction with glutamate
D) identification of glands in the oral cavity that release saliva in response to the presence of glutamate

Question 28

The distance between an axon terminal and the receiving cell must be very small because

A) the plasma membranes of the two cells must be almost touching for action potentials to pass from one to the other.
B) neurons use the diffusion of neurotransmitters to transmit stimuli between cells,and diffusion is only rapid over short distances.
C) the short distance creates a large surface area so that the receiving cell can receive a large number of neurotransmitters at once,ensuring rapid signal transmission.
D) the short distance allows sodium to be exchanged between the two cells,ensuring that the receiving cell has enough sodium to create an action potential.

Question 29

Which area of our brain acts as a "traffic manager"?

A) the thalamus
B) the cerebral cortex
C) the pons
D) the cerebellum

Question 30

The cerebral cortex of the human brain is much more highly and intricately folded than the same region in other animals.Why might this be the case?

A) The folds create more surface area for the production and release of the hormones that allow the human nervous system to interact with the endocrine system.
B) The folds are the remnants of the compression of the brain that occurs during childbirth.
C) The folds increase the surface area available for the complex thoughts and processing that occur in that region of the human brain.
D) Evolution has caused the brain to increase in size faster than the skull has increased in size.Folding allows our larger brain to more easily fit into our skull.

Question 31

Which of the following is NOT one of the three major regions of the human brain?

A) the medulla
B) the forebrain
C) the midbrain
D) the hindbrain

Question 32

In the eyes of animals that are primarily active at night,such as raccoons,the retina would

A) contain mostly rods.
B) not have pupils.
C) focus images.
D) lack a fovea.

Question 33

A drug that inhibits the function of mechanoreceptors would affect your sense of

A) touch.
B) light.
C) individuality.
D) smell.

Question 34

Where would you expect to see an absence of neurotransmitters?

A) in a synapse
B) in a myelin sheath
C) in a synaptic cleft
D) in the terminus of an axon

Question 35

The cerebrum has four major lobes.Which of the following is one of these?

A) the parietal
B) the cerebellum
C) the thalamus
D) the medulla oblongata

Question 36

The brain has important interactions with the endocrine system.Which part of the brain directly stimulates the release of hormones from the pituitary gland?

A) the hypothalamus
B) the cerebrum
C) the cerebellum
D) the central cortex

Question 37

To best help it sniff out a fox,a hunting dog probably has a high concentration of

A) chemoreceptors in its nasal cavity.
B) mechanoreceptors in its ears.
C) proprioceptors in its nasal cavity.
D) thermoreceptors in its front paws.

Question 38

Which of the following is FALSE?

A) Both the eye and the camera can adjust their focus to account for how far away an object is located.
B) Both the eye and the camera have lenses that bend light waves.
C) Both the eye and the camera have mechanisms to control the amount of light that enters.
D) Both the eye and the camera focus by changing the distance between the lens and the surface that reacts to light.

Question 39

The area of the brain that filters and sorts signals from the spinal cord also determines which signals require an action without awareness and which signals need to be sent to the conscious perception centers.This area of the brain is known as the

A) cerebrum.
B) pituitary gland.
C) thalamus.
D) cortex.

Question 40

Which of the following would NOT be found in the eyes of a horse?

A) rods
B) lenses
C) proprioceptors
D) pigments

Question 41

The axons of many individual neurons may be bundled together to form communication pathways known as ________.

Question 42

The ________ nervous system ferries signals to and from the central nervous system.

Question 43

As a whole,the nervous system converts stimuli into ________ input-action potentials that convey information about stimuli.

Question 44

A signal-sending neuron releases a ________,a molecule that carries the signal across the synapse between nerve cells.

Question 45

Nodes of Ranvier are found only in ________ neurons.

Question 46

The brain and spinal cord make up the ________ nervous system.

Question 47

Air pressure between the middle and outer ear is equalized by the

A) basilar membrane.
B) eustachian tube.
C) cochlea.
D) organ of Corti.

Question 48

The position of our body is reported by mechanoreceptors called ________.

Question 49

The figure below illustrates the organ of Corti,a part of the cochlea in the human inner ear.

What labeled region of this figure of the organ of Corti is directly stimulated to vibrate in response to the air movements caused by sound?

A) Region A
B) Region B
C) Region C
D) Region D

Question 50

The center of the human retina has a region called the ________ where cones are most densely packed.

Question 51

A person who,as a result of a mutation,could NOT produce one of the pigment molecules found in cones

A) would have difficulty seeing some or all colors.
B) could not see black and white.
C) could see only at night and under low light conditions.
D) would not be able to detect light of any color.

Question 52

The cerebrum has four major lobes: the parietal lobe,the frontal lobe,the temporal lobe,and the ________ lobe.

Question 53

When a signal causes sodium ions to flow into a neuron it becomes ________.

Question 54

We perceive pressure waves in air as ________.

Question 55

Examine the figure below.

The path of the arrows in this figure indicates the movement of ________ through a neuron.

Question 56

In research with mice,scientists found that proper amounts of sleep may help the brain

A) remove cellular waste.
B) enlarge.
C) remove glial cells.
D) react to stimuli more slowly.

Question 57

The figure below depicts a human eye.

When focusing on an object that is far away,the structure indicated by the arrow in the figure above

A) becomes flatter.
B) becomes more spherical.
C) does not change.
D) decreases in diameter.

Question 58

The flow of ions across an axon's plasma membrane generates an electrical impulse known as the ________.

Question 59

Neurotransmitters are released into a synaptic cleft by the process of ________.

Question 60

In vertebrates,special cells produce an insulating sheath of ________ that wraps around the axon of a neuron.

Question 61

An action potential weakens with distance traveled.

Question 62

One interneuron can send signals to the peripheral nervous system and the brain at the same time.

Question 63

When the difference in charge across a neuron's cell membrane decreases,the cell is depolarizing.

Question 64

Action potentials can only occur at the nodes of Ranvier.

Question 65

In regard to the peripheral nervous system (PNS),signals that occur involuntarily are under autonomic control.

Question 66

Brain activity rises during ________ sleep.

Question 67

The cell indicated by the arrow in the figure below directly interacts with environmental stimuli.

Question 68

A neurotransmitter can inhibit the formation of an action potential in a receiving cell.

Question 69

Brain activity is the same in all vertebrates during sleep.

Question 70

In bright light,the openings in the pupils of our eyes become smaller.

Question 71

To respond to an incoming signal,such as your fingertip being burned by a candle's flame,the signal must be transmitted to the brain before your muscles can be told to respond and pull away.

Question 72

Everyone who abuses drugs from an early age will become an addict.

Question 73

A resting neuron is negatively charged inside relative to the outside.

Question 74

Neurotransmitters move from dendrites to cell bodies to axons.

Question 75

Action potentials and resting potentials are the same thing.

Question 76

Action potentials can transmit information rapidly but weaken as they move along a neuron.