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Physiology > Chapter 06: Neuronal Signaling > Flashcards

Chapter 06: Neuronal Signaling Flashcards

0
Q

What are varicosities?

A

A series of bulging areas along the axon that release neurotransmitters

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1
Q

What are collaterals?

A

Branches that stem off of the axon

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2
Q

What are the myelin-forming cells of the CNS?

A

Oligodendrocytes

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3
Q

What are the myelin-forming cells of the PNS?

A

Schwann cells

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4
Q

How many axons can oligodendrocytes myelinate and connect to?

A

Up to 40

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5
Q

How may axons can Schwann cells myelinate and connect to?

A

Just one

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6
Q

What is the gap between areas of myelinated axon sheath called?

A

Nodes of Ranvier

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7
Q

Kinesin proteins bond __________ to the microtubule in the axon chain.

A

secretory vesicles

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8
Q

Dynein proteins bond _________ to the microtubule in the axon chain.

A

recycled membrane vesicles

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9
Q

Neurons make up _____% of the cells in the CNS but compose ____% of the volume.

A

10% of CNS cells, 50% CNS volume

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10
Q

What are the four types of neuroglial cells?

A

Oligodendrocytes, astrocytes, microglia, and ependymal cells

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11
Q

What are microglia?

A

Macrophage-like cells that perform immune function for CNS

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12
Q

What are the functions of astrocytes?

A

Regulate composition of extracellular fluid, stimulate formation of tight junctions that compose blood-brain barrier, provide glucose and remove ammonia for neurons

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13
Q

What are ependymal cells?

A

Producers and regulators of CSF that line the fluid filled cavities of the CNS

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14
Q

What is the growth cone?

A

Specialized enlargement that forms tip of extending axons that is involved in finding correct route and final destination

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15
Q

What are the growth factors for neural tissue called?

A

Neurotrophic factors

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16
Q

What is apoptosis?

A

Programmed self-destruction of cell

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17
Q

What percentage of newly formed neurons and synapses go through apoptosis?

A

50-70%

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18
Q

current (n.)

A

the movement of electric charge

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19
Q

resistance (n.)

A

hindrance to the flow of electric charge/current

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20
Q

What is the equation for Ohm’s Law?

A

I = V/R

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21
Q

membrane potential (n.)

A

the state of the negative charge of the inside of a cell relative to the outside

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22
Q

What is the range of resting membrane potentials for all cells?

A

-5 to -100 mV

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23
Q

What is the range for RMP in neurons?

A

-40 to -90 mV

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24
Q

What is average RMP for neurons?

A

-70 mV

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25
Q

What are the general permeabilities of K+, Na+, and Cl-?

A 
P(K+) = 1
P(Na+) = 0.04
P(Cl-) = 0.45
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26
Q

What is the ionic flow of the Na+/K+ ATPase pump?

A

3 Na+ out, 2 K+ in

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27
Q

leak channel (n.)

A

open channel, the flow of which follows concentration gradient

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28
Q

What are the stages of the firing of an action potential?

A

Depolarization, overshoot, repolarization, hyperpolarization, afterhyperpolarization

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29
Q

What is plasticity?

A

The remodeling of neural tissue in response to stimulation or injury

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30
Q

What is the rate of axon regrowth?

A

1 mm/day

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31
Q

electrical potential (n.)

A

the potential of opposite, separated electrical charges to do work if brought together

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32
Q

Which ion has a high concentration intracellularly?

A

K+

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33
Q

Which ion has a high concentration extracellularly?

A

Na+ (also Cl-)

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34
Q

electrogenic pump (n.)

A

pump that moves net charge across a membrane and contributes directly to membrane potential

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35
Q

excitability (n.)

A

the ability of a cell to generate an action potential

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36
Q

inactivation gate (n.)

A

part of a voltage-gated Na+ channel that blocks flow shortly after the channel opens

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37
Q

What is the threshold level for most neurons?

A

-55 mV

38
Q

relative refractory period (n.)

A

period during afterhyperpolarization in which only a very strong stimuli will generate an AP

39
Q

graded potential (n.)

A

change in potential of variable amplitude and duration that is conducted incrementally (no threshold/refractory period) and has a decremental flow of current

40
Q

What is a threshold stimulus?

A

A stimulus that generates a change in potential ~15 mV more positive than RMP

41
Q

absolute refractory period (n.)

A

period in which the VG-Na+ channels are open or inactivated; during this period, no stimuli will generate an AP

42
Q

equilibrium potential (n.)

A

the electrical potential at a membrane at which there is no net flux of the ion

43
Q

What is equilibrium potential for Na+?

A

+60 mV

44
Q

What does the Nernst equation calculate?

A

Equilibrium membrane potential for a single ion species based solely on concentration, measured in mV

45
Q

What is the threshold level for most neurons?

A

-55 mV

46
Q

What is the Nernst equation?

A

E = 60/Z * log (C(o)/C(i))

47
Q

What is equilibrium potential for K+?

A

-90 mV

48
Q

What percentage of RMP is contributed by the Na+/K+ATPase pump? What is the charge?

A

Up to 20%, about -15 mV

49
Q

Where is the first place in the neuron that an action potential can occur?

A

Axon hillock

50
Q

Where are action potentials found in the neuron?

A

The axon hillock and along the axon

51
Q

anterograde conduction (n.)

A

conduction away from the soma/dendrite of the neuron towards the axon terminal

52
Q

retrograde conduction (n.)

A

conduction away from the axon terminal towards the soma/dendrites

53
Q

At what stage of the conduction of an action potential is the relative refractory period?

A

Afterhyperpolarization

54
Q

reaction time (n.)

A

delay between stimulus and response (reflex or voluntary)

55
Q

synaptic delay (n.)

A

the amount of time it takes to release and bind neurotransmitters and depolarize the membrane to threshold in the postsynaptic axon hillock

56
Q

How large are neuronal synaptic clefts?

A

roughly 10-20 nm

57
Q

How long is the synaptic delay?

A

~ 200 ms (0.2 sec)

58
Q

What protein mediates final fusion of vesicles to the synaptic membrane?

A

Synaptotagmin

59
Q

What does the Goldman equation calculate?

A

Equilibrium membrane potential for several ions based upon concentration and permeability, measured in mV

60
Q

What is the signal pathway for all parasympathetic innervation?

A

Preganglionic neuron > nicotinic receptor > postganglionic neuron > muscarininc receptor > gland or smooth muscle

61
Q

What is the signal pathway for most sympathetic innervation?

A

Preganglionic neuron > nicotinic receptor > postganglionic neuron > adrenergic receptor > glands and visceral organs

62
Q

What is the less common signaling pathway for sympathetic innervation?

A

Preganglionic neuron > nicotinic receptor > postganglionic neuron > muscarinic receptor > sweat glands and blood vessels

63
Q

What type of receptor is between the preganglionic and postganglionic neurons in the ANS?

A

Nicotinic receptors

64
Q

What is the signaling pathway in somatic nervous innervation?

A

Lower motor neuron > nicotinic receptor > skeletal muscle

65
Q

sensation (n.)

A

sensory information that reaches the consciousness

66
Q

perception (n.)

A

a person’s understanding of the sensation’s meaning

67
Q

sensory information (n.)

A

information process by the sensory system, regardless of whether the information reaches consciousness

68
Q

What kind of receptor does norepinephrine bind to?

A

Adrenergic

69
Q

What neurotransmitter is released by postganglionic sympathetic neurons?

A

Norepinephrine

70
Q

What neurotransmitter is released by postganglionic parasympathetic neurons?

A

Acetylcholine

71
Q

What neurotransmitter is released by preganglionic sympathetic neurons?

A

Acetylcholine

72
Q

Which type of receptor that binds acetylcholine released by the parasympathetic system is commonly found on cells of effector organs?

A

Muscarinic

73
Q

What do mechanoreceptors respond to?

A

Mechanical stimuli (e.g., touch-pressure)

74
Q

What do thermoreceptors respond to?

A

Sensations of cold and warm

75
Q

What do photoreceptors do?

A

Convert light energy into graded potentials

76
Q

What do chemoreceptors respond to?

A

Respond to binding of chemicals to specific receptors on membrane (used in smell, taste, blood O2 and CO2)

77
Q

What do nociceptors respond to?

A

Respond to a number of painful stimuli including heat and tissue damage

78
Q

What are the five general classes of sensory receptors?

A

Mechanoreceptors, thermoreceptors, photoreceptors, chemoreceptors, and nociceptors

79
Q

stimulus transduction (n.)

A

transformation of energy into electrical signal

80
Q

sensory adaptation (n.)

A

decrease in receptor sensitivity with constant stimulation

81
Q

What do Meissner’s corpuscles sense?

A

Light touch

82
Q

What do Merkle’s corpuscles detect?

A

Medium touch

83
Q

What do free nerve endings detect?

A

Pain

84
Q

What do lamellated (Pacinian) corpuscles detect?

A

Deep pressure

85
Q

What do Ruffini corpuscles detect?

A

Warmth

86
Q

What are nociceptors?

A

Unspecialized free nerve endings that detect various “painful” stimuli

87
Q

What neurotransmitter would be increasingly released by post-ganglionic sympathetic cells in fight or flight?

A

Norepinephrine

88
Q

What neurotransmitter would be increasingly released by pre-ganglionic sympathetic cells in fight or flight?

A

Acetylcholine

89
Q

What does relative refractory period prevent?

A

Retrograde movement of action potentials

90
Q

What does binding ACh to nicotinic receptors in a single synapse cause in a post-synaptic cell?

A

Excitatory Post-Synaptic Potential (EPSP)

91
Q

What molecule directly causes GABA exocytosis from a pre-synaptic axon terminal?

A

Calcium

92
Q

What type of ion channel is associated with the production of graded potentials?

A

Voltage-gated channel

Physiology (9 decks)

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