What are nerve cells and nerve impulses? - Exams 1b

Questions

Question 1

Neurons differ most strongly from other body cells in their ____.

1. mitochondria
2. shape
3. temperature
4. osmotic pressure

Question 2

The two basic kinds of cells in the nervous system are _____.

1. dendrites and axons
2. neurons and axons
3. neurons and glia
4. ribosomes and lyosomes

Question 3

Water, oxygen, and ____ most freely flow across a cell membrane.

1. calcium
2. carbon dioxide
3. magnesium
4. positively charged ions

Question 4

Which scientific work did Cajal apply to his study of infant brains?

1. Galileo's invention of the telescope
2. Camillo Golgi's cell staining method
3. Charles Sherrington's study of refelxes
4. Perves & Hadley's dye injection method

Question 5

The structure that contains a cell’s chromosomes is called the ____.

1. nucleus
2. mitochondrion
3. endoplasmic reticulum
4. ribosome

Question 6

What do neurons have that other cells do not?

1. protein channels
2. large, branching extensions
3. an endoplasmic reticulum
4. a plasma membrane

Question 7

Small, charged molecules can cross the cell membrane through ____.

1. diffusion
2. protein channels
3. mitochondria
4. ribosomes

Question 8

Santiago Ramon y Cajal demonstrated that ____.

1. action potentions follow the all-or-none law
2. neurons are seperate from one another
3. at rest, the neuron has a negative charge inside its membrane
4. neurons communicate at specialized junctions called synapses

Question 9

What structure is composed of two layers of fat molecules that are free to flow around one another?

1. the membrane
2. a ribosome
3. the endoplasmic reticulum
4. a mitochondrion

Question 10

The cell membrane is composed of two layers of _____.

1. protein
2. plasma
3. carbohydrate
4. fat

Question 11

Dendrites ____.

1. ​are thin fibers of constant diameter
2. are branching fibers that get narrower near their ends
3. ​are an insulating material that cover an axon ​
4. contain the nucleus, ribosomes, and other structures found in most cells

Question 12

The branching fibers that form the information-receiving pole of the nerve cells are called _____.

1. sensory neurons
2. motor neurons
3. dendrites
4. axons

Question 13

Many dendrites contain short outgrowths called spines that _____.

1. eliminate cell waste products
2. increase the speed of transmission
3. ​increase the surface area available for synapses
4. ​increase the symmetry of the cel.

Question 14

Protein channels allow ____ molecules to cross the cell membrane.

1. small charged
2. large charged
3. small uncharged
4. large uncharged

Question 15

As compared to dendrites, axons usually ____.

1. are shorter in length​
2. are covered with myelin
3. ​form the information-receiving pole of the neuron​
4. taper in diameter toward their periphery

Question 16

The surface of a dendrite is lined with specialized junctions through which the dendrite receives information from other neurons. What are these junctions called?

1. axons
2. synaptic receptors
3. sybaptic hillocks
4. glia

Question 17

The endoplasmic reticulum is a ____.

1. structure that seperates the inside of the cell from the outside
2. ​site where the cell synthesizes new protein molecules
3. network of thin tubes that transport newly synthesized proteins
4. structure that contains the chromosomes

Question 18

The insulating material that covers many vertebrate axons is called the ____.

1. cell body or soma
2. dendrite
3. myelin sheath
4. presynaptic terminal

Question 19

The tree-like branches of a neuron that receive information from other neurons are called _____.

1. dendrites
2. axons
3. soma
4. myelin

Question 20

Ribosomes are the part of a cell that ____.

1. breaks down harmful chemicals
2. transport proteins
3. performs metabolic activities
4. synthesizes new proteins

Question 21

Nodes of Ranvier are ____.

1. responsible for cell metabolism
2. gaps in the myelin of axons
3. ​spiny outgrowths on dendrites
4. ​also known as myelin sheath

Question 22

If you were to accidentally touch a hot stove with your hand, you would quickly pull your hand away. The information carried to the muscles in your arm to make them contract was carried by ____.

1. afferent neurons​
2. efferent neurons
3. ​intrinsic neurons​
4. sensory neurons

Question 23

A presynaptic terminal is also known as ____.

1. a node of Ranvier
2. an end bulb
3. myelin
4. a spine

Question 24

What type of neuron in the pons receives information only from other cells in the pons and sends information only to other cells in the pons?

1. afferent
2. efferent
3. intrinsic
4. inter-synaptic

Question 25

Neurons typically have one ____, but many ____.

1. dendrite; axons
2. axon; dendrites​
3. cell body; axons
4. ​dendrite; cell bodies

Question 26

An axon has many branches, each of which swells at its tip. These are known as ____.

1. efferent axons​
2. afferent axons
3. ​presynaptic terminals
4. ​intrinsic neurons

Question 27

Gaps in the insulating material that surrounds axons are known as ____.

1. ​nodes of Ranvier​
2. interpeduncular nuclei
3. ​presynaptic terminals​
4. myelin synapses

Question 28

As a general rule, axons convey information ____.

1. to surrounding glia
2. ​away from their own cell body
3. ​toward dendrites of their own cell​
4. toward their own cell body

Question 29

If all of a neuron's dendrites or axons were contained within the spinal cord, it would be considered a(n) ____ neuron.

1. ​efferent​
2. afferent
3. ​intrinsic
4. Purkinje

Question 30

Chemicals are released by axons ____.

1. into the junction between neurons
2. ​into the presynaptic terminal
3. through the efferent terminals​
4. to the mitochondria

Question 31

____ in the brain and spinal cord and ____ in the periphery are specialized types of glia that build the myelin sheaths that surround neurons.

1. Schwann cells; oligodendrocytes​
2. Oligodendrocytes; Schwann cells​
3. Microglia; oligodendrocytes​
4. Radial glia; Schwann cells

Question 32

Which type of glia remove waste material in the nervous system?

1. radial glia
2. Schwann cells
3. astrocytes
4. oligodendrocytes

Question 33

What type of glial cells myelinate axons in the brain and spinal cord?

1. radial glia
2. Schwann cells
3. astrocytes
4. oligodendrocytes

Question 34

Which type of glia release chemicals that modify the activity of neighboring neurons?

1. radial glia
2. Schwann cells
3. astrocytes
4. oligodendrocytes

Question 35

Glial cells ____.

1. ​are less numerous than neurons in the human brain.

2. occupy about ten times more space in the brain than do neurons.

3. ​transmit information over long distances within the central nervous system.

4. are smaller but more numerous than neurons in the human brain.

Question 36

Which type of glia builds myelin sheaths around axons in the periphery of the body?

1. radial glia
2. Schwann cells
3. astrocytes
4. oligodendrocytes

Question 37

Glial cells whose function most closely resembles that of the immune system are called ____.

1. Schwann cells​
2. oligodendrocytes​
3. microglia​
4. radial glia

Question 38

Radial glia ____.

1. Synchronize the activity of axons
2. wrap around the presynaptic terminals of several axons
3. ​guide the migration of neurons during embryonic development
4. build the myelin sheats that surround and insulate certain axons

Question 39

What type of glia helps to synchronize the activity of axons?

1. radial glia
2. Schwann cells
3. astrocytes
4. oligodendrocytes

Question 40

What mechanism prevents or slows some chemicals from entering the brain, while allowing others to enter?

1. a threshold
2. a blood-brain barrier
3. an endoplasmic wall
4. a differential-drug inhibiter

Question 41

Why do neurons rely so heavily on glucose as their source of nutrition?

1. ​Glucose is the only fuel that can be used even in the absence of vitamins.
2. ​Glucose is not used extensively by other parts of the body.
3. ​Neurons lack the enzymes necessary to metabolize other fuels.​
4. Other fuels do not readily cross the blood-brain barrier.

Question 42

Molecules that can cross the blood-brain barrier are usually ____.

1. neurotransmitters, such as dopamine
2. large, uncharged molecules, such as lactose
3. large, charged molecules
4. molecules that can dissolve in the facts od the capillary walls

Question 43

The membrane of a neuron is composed of ____ with ____ embedded in them.

1. enzene molecules; carbohydrates
2. proteins; neurotransmitters
3. ​fat molecules; proteins
4. ​carbohydrates; purines

Question 44

Why does the brain need thiamine?

1. ​as a source of fuel in case there is not enough glucose
2. to enable glucose to cross the blood-brain barrier
3. as a building block for making proteins
4. to enable it to metabolize glucose

Question 45

What happens to a virus that manages to cross the blood-brain barrier and enter the brain?

1. It is quickly destroyed by natural killer cells
2. It gets trapped in a neuron, and then both are destroyed by natural killer cells
3. It gets trapped in a glial cell, and then both are destoryed by natural killer cells
4. ​It remains there and may cause negative effects several years later.

Question 46

Korsakoff's syndrome ____.

1. is due to a breakdown of the blood-brain barrier
2. is marked by severe memory impairments
3. ​results from lack of oxygen to the brain
4. ​results from too much thiamine

Question 47

What is the main source of nutrition for vertebrate neurons?

1. sodium
2. complex carbohydrates
3. glucose
4. fats

Question 48

Glucose enters the brain via which type of transport?

1. indirect transport
2. ​direct transport
3. active transport
4. passive transport

Question 49

The major disadvantage of a blood-brain barrier is that ____.

1. ​many chemicals can easily diffuse into the brain
2. ​certain required chemicals must be actively transported
3. ​so much glucose is required to maintain it
4. viruses cannot escape

Question 50

What leads to Korsakoff's syndrome?

1. ​glial cells that over-reproduce and increase pressure in the brain
2. viruses that manage to cross the blood-brain barrier
3. ​thiamine deficiency due to chronic alcoholism
4. ​glucose deficiency due to chronic alcoholism

Question 51

What term describes the difference in voltage that typically exists between the inside and the outside of a neuron?

1. resting potential
2. shock gradient
3. generator potential
4. concentration gradient

Question 52

Which of the following describes selective permeability?

1. Only certain molecules are allowed to cross the membrane freely.
2. Only certain types of stimulation will result in an action potential.
3. Ions can only travel in certain directions across the membrane.
4. ​All molecules must pass through designated channels.

Question 53

When the neuronal membrane is at rest, the sodium channels ____.

1. allow sodium to leak out as a steady, continuous drip
2. ​are closed, so there is almost no flow of sodium
3. ​permit sodium ions to pass quickly and easily
4. ​are at equilibrium with potassium channels

Question 54

The resting potential is mainly the result of ____.

1. ​negatively charged proteins outside the cell
2. negatively charged proteins inside the cell
3. ​positively charged proteins outside the cell
4. ​positively charged proteins inside the cell

Question 55

When a neuron’s membrane is at rest, the concentration gradient tends to move sodium ____ the cell and the electrical gradient tends to move it ____ the cell.

1. into; into
2. into; out of
3. out of; into
4. out of; out of

Question 56

The resting potential of a neuron refers to the ____.

1. movement of ions to the outside of the neuron
2. ​net positive charge on the inside of the neuron
3. ​net negative charge on the inside of the neuron
4. ​ions which rest in one place in the cell

Question 57

When the neuronal membrane is at rest, the potassium channels ____.

1. permit potassium ions to pass quickly and easily
2. ​prohibit any movement of potassium ions
3. ​permit potassium ions to pass slowly
4. ​help to open up the sodium channels

Question 58

The idea that a neuron's membrane is polarized refers to a difference in electrical potential between ____.

1. the inside and the outside of the membrane
2. the axon hillock and the cell body
3. ​sodium ions and potassium ions
4. ​the axons and the dendrites

Question 59

When a neuron’s membrane is at rest, the concentration gradient tends to move potassium ____ the cell and the electrical gradient tends to move it ____ the cell.

1. into; into
2. into; out of
3. out of; into
4. out of; out of

Question 60

What is the approximate resting potential of the inside of a neuron's membrane, relative to the outside?

1. -70 millivolts
2. +10 millivolts
3. 0 millivolts
4. +90 millivolts

Question 61

Electrical gradients lead to the ____.

1. ​movement of ions to areas having opposite electrical charges
2. ​movement of ions to areas having the same electrical charges
3. general movement of ions out of the neuron
4. ​general movement of ions into the neuron

Question 62

Which event will increase the concentration gradient of sodium?

1. ​increasing membrane permeability to sodium ions
2. ​increasing membrane permeability to chloride ions
3. ​decreasing permeability to potassium ions
4. ​increasing activity of the sodium potassium pump

Question 63

The concentration gradient for potassium tends to ____.

1. ​push potassium out of the cell
2. push sodium out of the cell
3. push chloride out of the cell
4. ​draw potassium into the cell

Question 64

What is one major cause for the resting potential of a neuron's membrane?

1. ​a high permeability of the membrane to water molecules
2. ​a difference in size between axons and dendrites
3. the refractory period of the membrane
4. the sodium-potassium pump

Question 65

When the neuron is at rest, what is primarily responsible for moving potassium ions OUT of the cell?

1. a concentration gradient
2. an electrical gradient
3. both a concentration gradient and an electrical gradient
4. the sodium-potassium pump

Question 66

The concentration gradient refers to the ____.

1. difference in distribution for various ions between the inside and outside of the membrane
2. negatively charged proteins inside the cell
3. ​fact that the concentration of ions is greater on the outside of a neuron
4. ​fact that the concentration of ions is greater on the inside of a neuron

Question 67

Under which conditions would the sodium-potassium pump likely be far less effective in creating a concentration gradient?

1. if the glia-to-neuron ratio were higher
2. if dendrites were generally longer than axons
3. if selective permeability of the membrane did not exist
4. if it were an active transport system that required energy

Question 68

When a neuron is at rest, what is primarily responsible for moving potassium ions into the cell?

1. a concentration gradient
2. an electrical gradient
3. ​the sodium-potassium pump
4. both the sodium-potassium pump and electrical gradient

Question 69

The net effect of each cycle of the sodium-potassium pump is to ____.

1. decrease the number of positively charged ions outside the cell
2. ​decrease the number of positively charged ions within the cell
3. ​increase the number of positively charged ions within the cell
4. ​increase the number of negatively charged ions within the cell

Question 70

When a membrane is at rest, what attracts potassium ions to the inside of the cell?

1. an electrical gradient
2. a concentration gradient
3. both an electrical gradienr and a concentration gradient
4. neither an electrical gradient nor a concentration gradient

Question 71

When a membrane is at rest, what attracts sodium ions to the inside of the cell?

1. an electrical gradient
2. a concentration gradient
3. both an electrical gradienr and a concentration gradient
4. neither an electrical gradient nor a concentration gradient

Question 72

Which action will produce a hyperpolarization of a neuron?

1. ​applying a negative charge inside the neuron with a microelectrode
2. applying a positive charge inside the neuron with a microelectrode
3. ​increasing the membrane's permeability to sodium
4. ​decreasing the membrane's permeability to potassium

Question 73

Which action would depolarize a neuron?

1. decreasing membrane permeability to calcium
2. ​increasing membrane permeability to potassium
3. decreasing membrane permeability to sodium
4. ​increasing membrane permeability to sodium

Question 74

Ordinarily, stimulation of a neuron takes place ____.

1. ​at the synapse
2. ​through hyperpolarization
3. ​in the mitochondria
4. in the endoplasmic reticulum

Question 75

What action tends to open the sodium gates across a neuron's membrane?

1. hyperpolarization of the membrane
2. depolarization of the membrane
3. increase in the sodium concentration outside the neuron
4. passing the peak of the action potential and entering the refractory period

Question 76

Which of the following is an advantage of having a resting potential?

1. The toxic effects of sodium are minimized inside the cell.
2. No energy is required to maintain it.
3. ​The cell is prepared to respond quickly to a stimulus.
4. All of the ions are maintained in equal concentrations throughout the cytoplasm.

Question 77

What occurs when depolarization is less than the cell's threshold?

1. ​Sodium is prevented from crossing the membrane.
2. Sodium crosses the membrane only slightly more than usual.
3. ​Potassium is prevented from crossing the membrane.
4. ​The cell will still produce an action potential.

Question 78

A membrane produces an action potential whenever the potential across it reaches what level?

1. the resting potential
2. -90 mV
3. the threshold of excitation
4. the refractory period

Question 79

What occurs when a stimulus shifts the potential inside a neuron from the resting potential to a more negative potential?

1. an action potential
2. depolarization
3. hyperpolarization
4. a threshold

Question 80

The action potential of a neuron depends mostly on what movement of ions?

1. ​sodium ions leaving the cell
2. sodium ions entering the cell
3. ​​potassium ions leaving the cell
4. potassium ions entering the cell

Question 81

At what point do the sodium gates begin to close, shutting out further entry of sodium into the cell?

1. ​at the peak of the action potential
2. ​when the threshold is reached
3. at the end of the relative refractory period
4. ​when the concentration gradient for sodium is eliminated

Question 82

When the potential across a membrane reaches threshold, the sodium channels ____.

1. ​open to let sodium enter the cell rapidly
2. close to prevent sodium from entering the cell
3. ​open to let sodium exit the cell rapidly
4. ​close to prevent sodium from exiting the cell

Question 83

After the peak of an action potential, what prevents sodium ions from continuing to enter the cell?

1. ​There is no longer a concentration gradient for sodium.
2. The sodium-potassium pump greatly increases its rate of activity.
3. All the available sodium ions have already entered the cell.
4. The sodium gates in the membrane close.

Question 84

In the normal course of an action potential, ____.

1. ​sodium channel remain open for long periods of time
2. the concentration of sodium equalizes across the membrane
3. sodium remains much more concentrated outside than inside the neuron
4. subthreshold stimulation intensifies the action potential

Question 85

What causes potassium ions to leave the axon just after the peak of the action potential?

1. ​a continuing concentration gradient and the opening of the potassium gates
2. ​an increase in the concentration gradient across the membrane
3. an increased tendency of the sodium-potassium pump to push potassium out
4. binding of potassium ions to proteins that leave at this time

Question 86

A drug will prevent an action potential if it ____.

1. ​lowers the threshold of the membrane​

2. blocks the movement of potassium across the membrane

3. blocks the movement of sodium across the membrane

4. increases the movement of sodium across the membrane

Question 87

Voltage-activated channels are channels for which a change in the voltage across the membrane alters their ____.

1. permeability
2. number
3. length
4. threshold

Question 88

A drug that blocks the sodium gates of a neuron's membrane will ____.

1. ​decrease the threshold

2. block the action potential

3. cause repeated action potentials

4. eliminate the refractory period

Question 89

At the peak of the action potential, the electrical gradient of potassium ____.

1. is the same as during the resting potential
2. ​pushes potassium out of the cell
3. ​pulls sodium into the cell
4. ​pulls potassium into the cell

Question 90

Local anesthetic drugs attach to the sodium channels of the membrane, which ____.

1. ​allows sodium ions to enter and stop action potential
2. ​prevents potassium ions from entering and stopping action potential
3. ​allows potassium ions to enter and stop action potential
4. ​prevents sodium ions from entering and stopping action potential

Question 91

The speed of an action potential down an unmyelinated axon is best described as ____.

1. ​the speed of electricity, regardless of the size of the axon
2. ​less than 1 meter per second, regardless of the size of the axon
3. ​faster in thin axons than in thick ones
4. ​faster in thick axons than in thin ones

Question 92

The function of a myelin sheath is to ____.

1. ​prevent action potentials from traveling in the wrong direction

2. ​increase the velocity of transmission along an axon

3. ​increase the magnitude of an action potential

4. provide a store of nutrients for the neuron

Question 93

The primary feature of a neuron that prevents the action potential from traveling back from where it just passed is the ____.

1. ​concentration gradient

2. ​refractory period

3. ​sodium potassium pump

4. ​phospholipid bilayer

Question 94

According to the all-or-none law, ____.

1. ​all neurons produce an action potential at the same time or none at all
2. ​once an axon reaches threshold, the amplitude and velocity of an action potential are nearly equal each time
3. ​all of the extracellular sodium enters the axon, or none at all
4. ​neurons are either active all the time or not at all

Question 95

What will most affect the speed of an action potential?

1. ​the strength of the stimulus
2. ​the time since the last action potential
3. ​the length of the axon
4. ​the resistance of the membrane

Question 96

In what direction does a local neuron transmit information?

1. ​through its dendrites to cell body to axon​
2. through its axon to cell body to dendrites
3. ​only toward the cell body
4. ​equally well in any direction

Question 97

During the relative refractory period, the ____.

1. ​sodium gates are firmly closed

2. ​sodium gates are reverting to their usual state

3. ​sodium gates are wide open

4. ​potassium gates are firmly closed

Question 98

Which of the following describes the transmission of information in a local neuron?

1. The signal decreases in strength as it travels.​
2. The signal increases in strength as it travels.​
3. Local neurons do not transmit any information.​
4. The signal strength remains constant as it travels.

Question 99

The all-or-none law states that ____.

1. ​a neuron produces an action potential of maximal strength, or none at all

2. ​all neurons fire or none at all

3. ​all neurons in a pathway fire at the same time, or none do

4. ​all ions move in the same direction, or none do

Answers

Question 1

B

Question 2

C

Question 3

B

Question 4

C

Question 5

B

Question 6

B

Question 7

B

Question 8

B

Question 9

A

Question 10

D

Question 11

B

Question 12

C

Question 13

C

Question 14

A

Question 15

B

Question 16

B

Question 17

C

Question 18

C

Question 19

A

Question 20

D

Question 21

B

Question 22

B

Question 23

B

Question 24

C

Question 25

B

Question 26

C

Question 27

A

Question 28

B

Question 29

C

Question 30

A

Question 31

B

Question 32

C

Question 33

D

Question 34

C

Question 35

D

Question 36

B

Question 37

C

Question 38

C

Question 39

C

Question 40

B

Question 41

D

Question 42

D

Question 43

C

Question 44

D

Question 45

D

Question 46

B

Question 47

C

Question 48

C

Question 49

B

Question 50

C

Question 51

A

Question 52

A

Question 53

B

Question 54

B

Question 55

A

Question 56

C

Question 57

C

Question 58

A

Question 59

C

Question 60

A

Question 61

A

Question 62

D

Question 63

A

Question 64

D

Question 65

A

Question 66

A

Question 67

C

Question 68

D

Question 69

B

Question 70

A

Question 71

C

Question 72

A

Question 73

D

Question 74

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Question 75

B

Question 76

C

Question 77

B

Question 78

C

Question 79

C

Question 80

B

Question 81

A

Question 82

A

Question 83

D

Question 84

C

Question 85

A

Question 86

C

Question 87

A

Question 88

B

Question 89

B

Question 90

D

Question 91

D

Question 92

B

Question 93

B

Question 94

B

Question 95

D

Question 96

D

Question 97

B

Question 98

A

Question 99

A