Physiological Final Ch 2

Front 1

What is the order of transmission of information within a neuron?
arrange: cell body, dendrite, axon

Back 1

dendtrite, cell body, axon

Front 2

What are the two kinds of cells in the nervous system?

Back 2

neurons and glia

Front 3

Neurons differ most strongly from other body cells in their:

Back 3

shape

Front 4

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

Back 4

It stays in the nervous system throughout a person's life

Front 5

Neurons typically have one ____, but many ____.

Back 5

axon, dendrites

Front 6

Glucose enters the brain via:

Back 6

active transport

Front 7

What would a neuron in the pons be called that receives information only from other cells in the pons and sends information only to other cells in the pons?

Back 7

intrinsic

Front 8

What receives excitation from other neurons and conducts impulses to muscle or gland cells?

Back 8

motor neurons

Front 9

Why does the brain need thiamine?

Back 9

To enable it to metabolize glucose the brain needs ________

Front 10

Incoming synapses are primarily found on:

Back 10

dendrites and cell bodies

Front 11

Who is most likely to suffer from a thiamine deficiency?

Back 11

alcoholics

Front 12

Which chemicals flow most freely across a cell membrane?

Back 12

water, oxygen, carbon dioxide

Front 13

A greater amount of branching on dendrites allows them to:

Back 13

dendrites have a larger surface area available for receiving information from other neurons when they have _______.

Front 14

In the brain, an arrangement of endothelial cells:

Back 14

does not allow most molecules to pass because the cells are so tightly packed

Front 15

Chemicals are released by axons:

Back 15

into the junctions between the neurons

Front 16

One type of glia helps synchronize the activity of axons. They are called:

Back 16

astrocytes

Front 17

Where do the metabolic activities occur that provide energy for all of the other activities of the cell?

Back 17

mitochondria does what for the cell?

Front 18

Myelin covers:

Back 18

Some axons in vertebrates and non in invertebrates are covered by _______.

Front 19

What is the main source of nutrition for vertebrate neurons?

Back 19

glucose is the main source of ___________ for neurons

Front 20

Korsakoff's syndrome is marked by:

Back 20

severe memory impairments

Front 21

What are dendrites?

Back 21

branching fibers that get narrower at their ends are called:

Front 22

What leads to Korsakoff's syndrome?

Back 22

A thiamine deficiency caused by alcoholism causes what?

Front 23

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

Back 23

other fuels do not readily cross the blood-brain barrier

Front 24

Ribosomes are the part of a cell that:

Back 24

synthesize new proteins

Front 25

Which of the following is NOT a characteristic of a dendrite?

Back 25

it is in contact with dendrites of other neurons

Front 26

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

Back 26

a blood-brain barrier

Front 27

What is the point from which an axon releases chemicals into the synapse?

Back 27

the presynaptic terminal

Front 28

Compared to passive transport, the major disadvantage of active transport is that it:

Back 28

requires the expenditure of energy

Front 29

Nodes of Ranvier are:

Back 29

the gaps in myelin of axons

Front 30

The insulating material which covers many vertebrate axons is called the:

Back 30

myelin sheath

Front 31

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

Back 31

Schwann Cells

Front 32

What are two requirements for the brain to metabolize glucose?

Back 32

thiamine and oxygen

Front 33

The risk of having part of the brain unprotected by the blood-brain barrier is:

Back 33

Both chemical interference with neurotransmitters and increased risk for viruses and toxic chemicals are correct

Front 34

Glial cells:

Back 34

do not transmit information over long distances

Front 35

The endoplasmic reticulum is a:

Back 35

network of thin tubes that transport newly synthesized proteins

Front 36

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

Back 36

ogliodendrocytes

Front 37

The major disadvantage of a blood-brain barrier is that:

Back 37

certain required chemicals must be actively transported

Front 38

Which of the following is a characteristic of glial cells in the human brain?

Back 38

they are more numerous than neurons

Front 39

The information sender of the neuron, conveying an impulse toward either other neurons or a gland or muscle is called the:

Back 39

the axon

Front 40

In contrast to dendrites, axons:

Back 40

may be covered in myelin

Front 41

Molecules that can cross the blood-brain barrier are usually:

Back 41

molecules that can dissolve in the fats of the capillary walls

Front 42

Many dendrites contain short outgrowths called spines which:

Back 42

increase the surface area available for synapses

Front 43

Some dendrites contain additional short outgrowths. What are these outgrowths called?

Back 43

dendritic spines

Front 44

As a general rule, where do axons convey information?

Back 44

away from their own cell body

Front 45

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:

Back 45

efferent neurons

Front 46

The structure that contains the chromosomes is called the:

Back 46

nucleus

Front 47

A presynaptic terminal is also known as:

Back 47

an end bulb

Front 48

Chemicals than cannot flow freely across a cell membrane enter a neuron through:

Back 48

specialized protein channels

Front 49

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

Back 49

dendrites

Front 50

the most important consideration in developing a drug that will act in the brain is:

Back 50

if the drug will cross the blood-brain barrier

Front 51

Radial glia:

Back 51

guide the migration of neurons in embryonic development

Front 52

Which function is NOT performed by glia?

Back 52

transmitting information

Front 53

Glial cells

Back 53

occupy the same total space as do neurons

Front 54

Protein channels, allow ____ to cross the cell membrane.

Back 54

small charged molecules

Front 55

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

Back 55

microglia

Front 56

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

Back 56

-70mV

Front 57

Which of the following events would increase the concentration gradient of sodium?

Back 57

Increased activity of the sodium potassium pump

Front 58

Which feature of a neuron limits the number of action potentials it can produce per second?

Back 58

the absolute refractory period

Front 59

Which of the following actions would depolarize a neuron?

Back 59

Increasing membrane permeability to sodium

Front 60

When a neuron's membrane is at rest, which of the following molecules crosses through it MOST slowly?

Back 60

potassium

Front 61

In a myelinated axon, where are sodium gates abundant?

Back 61

Nodes of Ranvier

Front 62

If there is a depolarizing effect on a neuron, the result will be that the neuron will fire:

Back 62

only if it reaches threshold

Front 63

If you were to stub your toe and feel the pressure a second or two before you feel the pain, then which of the following statements is most likely true?

Back 63

pressure sensitive neurons are large and myelinated

Front 64

Which of the following is TRUE of local neurons?

Back 64

they have short dendrites and axons

Front 65

What are the nodes of Ranvier?

Back 65

Gaps in the myelin sheath

Front 66

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

Back 66

the cell is prepared to respond quickly to any stimulus

Front 67

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.

Back 67

out of, into

Front 68

The sodium-potassium pump, repeatedly transports three ____ ions out of the cell while drawing two ____ ions into it.

Back 68

Sodium, potassium

Front 69

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

Back 69

sodium gates in the membrane close

Front 70

When the neuron is at rest, what is responsible for moving sodium ions out of the cell?

Back 70

the sodium potassium pump

Front 71

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.

Back 71

into, into

Front 72

What disease is related to the destruction of myelin sheaths?

Back 72

multiple sclerosis

Front 73

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

Back 73

resting potential

Front 74

Which of the following describes selective permeability?

Back 74

only certain molecules are allowed to cross the membrane freely

Front 75

At the peak of the action potential, the electrical gradient:

Back 75

pushes potassium out of the cell

Front 76

Which of the following would produce a hyperpolarization of a neuron?

Back 76

applying a negative charge inside the neuron with a micro electrode

Front 77

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

Back 77

depolarization of the membrane

Front 78

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

Back 78

the sodium potassium pump

Front 79

In what way is a myelinated axon that has lost its myelin (through disease) different from an axon that was never myelinated?

Back 79

it lacks sodium gates along parts of its surface

Front 80

How is the speed of an action potential down an unmyelinated axon BEST described?

Back 80

faster in thicker axons than thinner axons

Front 81

The neuron will produce an action potential only if the depolarization exceeds what level?

Back 81

the threshold of excitation

Front 82

In what direction does a local neuron transmit information?

Back 82

equally well in any direction

Front 83

Concentration gradients lead to what kind of movements?

Back 83

the movements of ions to areas of their lowest concentration

Front 84

The all-or-none law applies to:

Back 84

axons

Front 85

During the relative refractory period:

Back 85

the sodium gates are returning to their usual state

Front 86

When the potential across a membrane reaches threshold, the sodium channels:

Back 86

open to let sodium enter the cell rapidly

Front 87

The presence of an all-or-none law suggests that neurons can only convey different messages by changing their:

Back 87

rate or pattern of action potentials

Front 88

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

Back 88

a continuing concentration gradient and the opening of the potassium pumps

Front 89

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

Back 89

fat molecules; proteins

Front 90

If depolarization is less than the cell's threshold:

Back 90

sodium crosses the membrane only slightly more than usual

Front 91

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

Back 91

if the plasma membrane were generally permeable

Front 92

What is the result if a stimulus shifts the potential inside a neuron from the resting potential to a potential slightly closer to zero?

Back 92

depolarization

Front 93

When you state that the neuron's membrane is polarized, you are referring to a difference in electrical potential between:

Back 93

the inside and outside of the membrane

Front 94

Local anesthetic drugs, such as Novocain, work by:

Back 94

blocking the sodium gates

Front 95

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

Back 95

permeability

Front 96

Stimulus A depolarizes a neuron just barely above the threshold. Stimulus B depolarizes a neuron to 10 mV beyond threshold. What can we expect to happen?

Back 96

Stimulus A and Stimulus B will produce the same response in the neurons

Front 97

A drug that decreases the flow of potassium through the potassium gates of the membrane would:

Back 97

slow the return of the membrane to its resting potential

Front 98

To what does saltatory conduction refer?

Back 98

the transmission of an impulse along a myelinated axon

Front 99

Which of the following represents the all-or-none law?

Back 99

the size of the action potential is independent of the strength of the stimulus that initiated it

Front 100

The membrane of a neuron is specialized to:

Back 100

control the exchange of chemicals between the inside and outside of the cell

Front 101

During the entire course of events from the start of an action potential until the membrane returns to its resting potential, what is the net movement of ions?

Back 101

sodium in potassium out

Front 102

Ordinarily, stimulation of a neuron takes place:

Back 102

at the synapse

Front 103

Saltatory conduction ____ the velocity of action potentials, and ____ the amount of energy used by the neuron.

Back 103

increases, decreases

Front 104

The selectivity of a neuron membrane is analogous to?

Back 104

the blood-brain barrier

Front 105

At what point do the sodium gates start to allow sodium into the neuron?

Back 105

in response to any depolarization

Front 106

What happens once an action potential starts?

Back 106

it is regenerated at other points along the axon

Front 107

A drug that blocks the sodium gates of a neuron's membrane would:

Back 107

block the action potential

Front 108

In the normal course of an action potential:

Back 108

sodium remains much more concentrated on the outside than inside of the neuron

Front 109

What is the result if a stimulus shifts the potential inside a neuron from the resting potential to a more negative potential?

Back 109

hyperpolarization

Front 110

Negatively charged ions like ____ are mostly located outside the cell.

Back 110

chloride

Front 111

Electrical gradients lead to what kind of movements?

Back 111

the movement of ions to areas having the opposite charge

Front 112

Suppose we applied a drug to a neuron that caused its sodium gates to suddenly open wide. What would happen?

Back 112

an action potential

Front 113

Which of the following is NOT governed by the all-or-none law?

Back 113

local neurons

Front 114

Just after the peak of the action potential, what movement of ions restores the membrane to approximately the resting potential?

Back 114

potassium ions leave the cell

Front 115

The presence of myelin and the diameter of the axon:

Back 115

affect the speed of the action potential

Front 116

Why are local neurons more difficult to study?

Back 116

they are so small

Front 117

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

Back 117

sodium ions entering the cell

Front 118

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

Back 118

absolute refractory period

Front 119

What is meant by the term "concentration gradient" with respect to neurons?

Back 119

sodium and potassium ions are more concentrated on opposite sides of the membrane

Front 120

A neuron's sodium gates are firmly closed and the membrane cannot produce an action potential during:

Back 120

the absolutely refractory period

Front 121

The function of a myelin sheath is to:

Back 121

increase the velocity of the action potential along an axon

Front 122

The resting potential of a neuron refers to:

Back 122

the net negative charge on the inside of the neuron

Front 123

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

Back 123

the signal decreases in strength as it travels

Front 124

When the neuronal membrane is at rest, the sodium channels:

Back 124

are closed

Front 125

What will affect the speed of an action potential?

Back 125

the resistance of the membrane

Front 126

Where do most action potentials begin?

Back 126

at the axon hillock