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Physiology-Exam 2 > Neural tissue > Flashcards

Neural tissue Flashcards

1
Q

The ____ is the part of the neuron where the action potential begins

A

axon hillock

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2
Q

The ____ is the difference in charge across plasma membrane

A

membrane potential

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3
Q

The membrane potential is controlled by regulation of _____ across the plasma membrane

A

ion movement

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4
Q

Intracellular fluids are ____ (charge) and extracellular fluids are (charge)

A

neutral; neutral

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5
Q

The membrane potential is a result of what 2 things?

A

the immediate inside of the membrane is negatively charged and the immediate outside of the membrane is positively charged

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6
Q

The Na+/K+ pumps actively transport ions from ___ to ___ concentration

A

low to high

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7
Q

The extracellular space has a higher concentration of ___

A

Na+

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8
Q

The intracellular space has a higher concentration of ___

A

K+

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9
Q

__Na+ move out of the cell and __K+ move into the cell

A

3;2

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10
Q

In the plasma membrane, there are nongated ___ and ___ channels called leak channels, which allow ___ to leak out of the cell

A

K+ and Cl-; K+

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11
Q

The movement of K+ out of the cell causes what to happen

A

the cytoplasm immediately inside the plasma membrane to be negative

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12
Q

___ are repelled by negatively charged proteins inside the cell and are attracted to the Na+ ions outside the cell

A

Cl-

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13
Q

___ occurs when the difference in charge between the inside and outside of the cell becomes less negative/more positive

A

depolarization

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14
Q

____ occurs when the difference in charge between the inside and outside of the cell becomes more negative/less positive

A

hyperpolarization

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15
Q

The membrane potential is changed by decreasing or increasing the movement of ions across the plasma membrane by changing the ______ to the ions

A

membrane permeability

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16
Q

If the membrane becomes more permeable to Na+, then more Na+ diffuses into the cell resulting in depolarization

A

depolarization

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17
Q

If the membrane becomes more permeable to K+, then more K+ diffuses out of the cell resulting in

A

hyperpolarization

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18
Q

A ____ is caused by a stimulation that changes the permeability of the plasma membrane. This could be caused by chemical signals binding to receptor proteins, mechanical stimulation, temperature changes, absorption of light, or a change in voltage across the membrane

A

graded potential

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19
Q

Graded potentials occur on the ____ and _____ of the neurons

A

dendrites and cell bodies

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20
Q

Graded potentials spread over the _____ and the initial stimulus causes a change in permeability in one area

A

plasma membrane

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21
Q

Graded potentials spread in a _____ fashion–the magnitude ___ as they move farther from the site of the initial stimulus

A

decremental;decreases

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22
Q

Action potentials require ___-gated ion channels; threshold is the level required to open the channels

A

voltage

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23
Q

Voltaged-gated ion channels are on the ____ of the neurons

A

axons

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24
Q

Graded potentials vary in ___ depending on the strength of a stimulus; the amount of change in permeability is how much potential is created

A

magnitude

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25
Q

____ is when the magnitudes of graded potentials can be added to each other

A

summation

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26
Q

A depolarization of the postsynaptic membrane caused by an increase in the membrane permeability to Na+ is called an ____; it brings the membrane potential closer to the threshold

A

EPSP

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27
Q

A hyperpolarization of the plasma membrane caused by an increase in the membrane permeability of K+ is called an ____; it takes the membrane potential further from the threshold

A

IPSP

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28
Q

The RMP is typically about __

A

-70

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29
Q

Once the threshold value, ____, is reached, an AP will occur

A

-50

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30
Q

The depolarization phase of an action potential occurs when the membrane potential changes from ___ to ___

A

-50 to 20

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31
Q

The repolarization phase of an action potential occurs when the membrane potential changes from ___ to ___

A

20 to -70

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32
Q

There is a hyperpolarization after the repolarization of an action potential which is called the ____

A

afterpotential

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33
Q

When the cell is resting, the gated K+ channels are ___, the activation gates of Na+channels are ___, and the inactivation gates are ___

A

closed; closed; open

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34
Q

Once a cell reaches threshold, activation gates of multiple Na+ channels ____ and Na+ diffuses into the cell; The K+ channels ____ but more slowly than the Na+ channels

A

open; open

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35
Q

In depolarization more ___ ions move into the cell than ___ ions move out so the difference in charge across the membrane becomes more positive

A

Na+; K+

36
Q

As the membrane potential approaches its maximum (20), the change in potential causes the inactivation of the Na+ channels to ___ and Na+ stops moving into the cell, while the K+ channels continue to ___ and more K+ moves out of the cell; K+ ions move out of the cell and the differences in charge across the membrane becomes more negative

A

close; open

37
Q

In the beginning of the afterpotential, the K+ channels remain ___ and more K+ moves out of the cell, the difference in charge across the membrane becomes more negative than the RMP, the activation gates of the Na+ channels ___ and the inactivation gates ___

A

open; close; open

38
Q

As the membrane potential approaches its minimum during the afterpotential, the K+ channels ___ and K+ stops moving out of the cell, and then the Na+/K+ pumps and leak channels return the cell to the RMP

A

close

39
Q

The ______ occurs once a cell is depolarized to the threshold level, an AP occurs, and another stimulus will not cause a greater action potential; during the repolarization, the inactivation gates of Na+ channels are closed and further stimulation will not cause another action potential

A

absolute refractory period

40
Q

The ____ occurs during the afterpotential, the inactivation gates of Na+ channels open, but the activation gates are closed; also, K+ channels are still open and causing hyperpolarization; a stimulus would have to be large enough to depolarize the cell to threshold while the K+ channels are still open

A

Relative refractory period

41
Q

An action potential is an all-or-none change in membrane permeability that can travel over the plasma membrane without decreasing the magnitude; the change in voltage across the membrane causes what?

A

more voltage-gated ion channels to open

42
Q

Neuron diameter affects the speed of propagation, meaning that a larger diameter will conduct an AP faster than a small since there is a larger surface area resulting in what?

A

more ion channels

43
Q

In myelinated neurons, ion channels are located where?

A

at nodes of ranvier

44
Q

In unmyelinated neurons, ion channels are located where?

A

all the way down the membrane

45
Q

At all of the ion channels on a neuron, ___ enters

A

Na+

46
Q

The ______ is directly proportional to the stimulus strength and the size of a graded potential

A

action potential frequency

47
Q

The nervous system is _____, which means that the frequency of action potentials determines the strength of the signal

A

frequency-modulated

48
Q

The endocrine system is ____, which means that the concentration of the hormone determines the strength of the signal

A

amplitude-modulated

49
Q

All action potentials have an equal magnitude (true/false)

A

true

50
Q

How is the strength of a sensory stimulus perceived?

A

the frequency of AP sent to the CNS by the neuron

51
Q

What does the strength of a muscle contraction depend on?

A

the frequency of AP sent to the muscle by the neuron

52
Q

The amount of gland secretion depends on what?

A

the frequency of AP sent to the gland by the neuron

53
Q

The number of action potentials that can occurs is limited (true/false)

A

true

54
Q

The action potential frequency is dependent on what?

A

the length of the absolute refractory period

55
Q

A subsequent AP cannot occur until the inactivation gates of the Na+ channels are ____ at the end of the repolarization phase

A

opened

56
Q

____ summation is when two or more presynaptic neurons stimulate one postsynaptic neuron and two graded potentials in two different areas of the cell are summed together

A

spatial

57
Q

___ summation is when one presynaptic neuron transmits two or more AP in close succession and the release of neurotransmitter is increased which causes two graded potentials in one area of the cell to be summed together (they occur close enough in time)

A

temporal

58
Q

In a ____ pathway, multiple presynaptic cells synapse on a few number of postsynaptic cells

A

convergent

59
Q

In a ____ pathway, a smaller number of presynaptic cells synapse on a larger number of postsynaptic cells

A

divergent

60
Q

In an ______ circuit, cells are arranged in a circular pattern

A

oscillating

61
Q

In a ____ pathway, multiple sensory neurons converge on one neuron in the CNS

A

convergent

62
Q

Some areas of the skin like the fingertips are highly sensitive and one sensory neuron will synapse with one CNS neuron, meaning that they are (convergent/not convergent)

A

not convergent

63
Q

Some areas of the skin like the back are not as sensitive and multiple sensory neurons converge onto one CNS neuron, meaning they are (convergent/not convergent)

A

convergent

64
Q

In a ___ pathway, a smaller number of presynaptic neurons synapse on a larger number of postsynaptic neurons

A

divergent

65
Q

One example of a divergent pathway is when ___ motor neuron controls ___ muscle fiber(s)

A

one; multiple

66
Q

One example of a divergent pathway is when ___ sensory neuron diverges to _____

A

different parts of the CNS

67
Q

Things like ventilation and locomotion are considered ____ pathways since a sensory stimulus can produce a prolonged response because of the circular arrangement until the circuit is fatigued or inhibited

A

oscillating circuit

68
Q

A cell can release a neuromodulator that influences the release of a neurotransmitter from another neuron; in _____ an inhibitory cell releases a neuromodulator that decreases the amount of neurotransmitter secreted by another neuron

A

presynaptic inhibition

69
Q

A cell can release a neuromodulator that influences the release of a neurotransmitter from another neuron; in ____ an excitatory cell releases a neuromodulator that increases the amount of neurotransmitter secreted by the other neuron

A

presynaptic facilitation

70
Q

_____ transport is when kinesin proteins transport from cell body to axon terminal

A

anterograde

71
Q

____ transport is when dynein proteins transport from axon terminal to cell body

A

retrograde

72
Q

The neuroglia located in the PNS and derived from neural crest cells are ____ and ___ cells

A

Schwann and satellite

73
Q

The neuroglia located in the CNS derived from neural tube cells are ___, ____, and ____ cells

A

oligodendrocytes, astrocytes, and ependymal cells

74
Q

The neuroglia located in the CNS derived from hematopoietic stem cells are ____

A

microglia

75
Q

____ help regulate the external chemical environment surrounding the neurons

A

Schwann cells

76
Q

Small cells that surround cell bodies in the PNS are called ____

A

satellite cells

77
Q

What to satellite cells do?

A

help regulate the external chemical environment surrounding neurons

78
Q

_____ are myelinated axons of neurons within the CNS

A

oligodendrocytes

79
Q

What do oligodendrocytes do?

A

regulate the external chemical environment surrounding neurons

80
Q

Astrocytes do what 5 things?

A

1-support neurons and capillaries in the CNS
2-regulate the external chemical environment surrounding neurons
3-guide migration of new neurons and formation of synapses
4-influence neuronal function and participate in information processing
5-storage and breakdown of glycogen

81
Q

How do astrocytes function at the blood-brain-barrier?

A

stimulate formation of tight junctions between capillary endothelial cells

82
Q

How do astrocytes control cerebral blood flow?

A

vasodilate and vasoconstrict arterioles

83
Q

How do astrocytes function in glial scar formation?

A

astroctyes fill in areas where damage to neurons has occurred in the CNS

84
Q

___ are immune cells in the CNS that recognize foreign cells and antigens, phagocytize them, and act as APCs

A

microglia

85
Q

_____ line the ventricles of the brain and the central canal of the spinal cord; they form choroid plexuses with blood capillaries and filter blood plasma to produce CSF

A

ependymal cells

86
Q

____ are the precursors of axons and dendrites that emerge from the cell body; at the ends of axons there are growth cones and dynamic extension and withdrawal of filopodia

A

neurites

87
Q

How are axons regenerated? 4 steps

A

1-axon becomes fragmented at site of injury
2-macrophages phagocytose the dead axon distal to the injury
3-axon grows at rate of 1.5 mm/day through regeneration tube formed by Schwann cells
4-axon regenerates and a new myelin sheath forms

Physiology-Exam 2 (5 decks)

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