LAB Final Part 2 (Nervous system) Flashcards Preview

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Flashcards in LAB Final Part 2 (Nervous system) Deck (108)
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1
Q

nerve cells that transfer information within the body

A

neurons

2
Q

what are the two types of signals that neurons use to communicate?

A

electrical signals (long-distance) and chemical signals (short-distance)

3
Q

what happens in the ganglia (clusters of neurons) and a more complex organization of neurons the brain?

A

processing of information

4
Q

what does neuron organization and structure reflect?

A

function in information transfer

5
Q

what does the neuron (cell) exempllify?

A

close fit between form and function

6
Q

where are most of the neuron’s organelles?

A

in the cell body

7
Q

what do most neurons have and what are they?

A

dendrites, highly branched extensions that receive signals from neurons

8
Q

what is the much longer extension that transmits signals to cells at synapses?

A

the axon

9
Q

the cone-shaped base of an axon

A

axon hillock

10
Q

the synaptic terminal of one axes passes information across the synapse in the form of chemical messengers

A

neurotransmitters

11
Q

a junction between an axon and another cell

A

synapse (synaptic cleft)

12
Q

how is information transferred?

A

from a presynaptic cell (a neuron) to a postsynaptic cell (a neuron, muscle or gland cell)

13
Q

what are most neurons nourished or insulated by?

A

cells called glia or glial cells

14
Q

what do sensors detect external stimuli and internal conditions and transmit information along?

A

sensory neurons

15
Q

where do sensory information get sent to the brain or ganglia?

A

where interneurons integrate the information

16
Q

what does the motor output leave the brain by and what does that trigger?

A

motor neurons, triggers muscle or gland activity

17
Q

what establishes the resting potential of a neuron?

A

ion pumps and ion channels

18
Q

the membrane potential of a neuron no sending signals

A

resting potential

19
Q

how do changes in membrane potential act act as?

A

signals, transmitting and processing information

20
Q

three stages of how the Nervous system processes information (SIM)

A

1) sensory output
2) integration
4) motor output

21
Q

where integration takes place, this includes the brain

A

central nervous system (CNS)

22
Q

carries information into and out of the CNS

A

peripheral nervous system (PNS)

23
Q

what does the neurons of the PNS when bundled together form?

A

nerves

24
Q

in a mammalian neuron at resting potential what concentration is the highest inside the cell and what is the highest outside the cell?

A

inside: K+
outside: Na+

25
Q

what does sodium-potassium pumps use the energy of ATP to maintain?

A

K+ and Na+ gradients across the plasma membrane

26
Q

what do the concentrations K+ and Na+ gradients represent?

A

chemical potential energy

27
Q

what do ion channels in the plasma membrane convert chemical potential into?

A

electrical potential

28
Q

characteristics of a neuron at resting potential(3) (MFK)

A

1) many open K+ channels
2) fewer open Na+ channels
3) K+ diffuses out of the cell

29
Q

what is the major source of membrane potential?

A

the resulting buildup of negative charge within the neuron

30
Q

types of ion channels (3) (SPS)

A

1) sodium/potassium pump
2) potassium (K+) channels
3) Sodium (Na+) channels

31
Q

what type of ion channel is sodium/potassium pump?

A

active

32
Q

characteristics of the ion channel, potassium (K+) channels (3) (PSS)

A

1) passive
2) some are always open
3) some are gated and closed when resting

33
Q

characteristics of the ion channel, Sodium (Na+) channels

A

1) passive

2) gated and closed when resting (only open for certain circumstances like membrane potential)

34
Q

what can resting potential be modeled by?

A

an artificial membrane that separates the two chambers

35
Q

charactertistics of the resting potential modeled by an artificial membrane (3) (CKN)

A

1) the concentration of KCI is higher in the inner chamber and lower in the outer chamber
2) K+ diffuses down its gradient to the outer chamber
3) negative charge (CI) builds up in the inner chamber

36
Q

what gradients are balanced at equilibrium?

A

both the chemical and electrical

37
Q

charateristics inside a resting potential (2) (CR)

A

1) the currents (net flow) of K+ and Na+ are equal and opposite
2) the resting potential across the membrane remains steady

38
Q

what are action potentials?

A

signals conducted by axons

39
Q

what do neurons contain that causes changes in membrane potential to occur that opens or close in response to a stimuli?

A

gated ion channels

40
Q

when gated K+ channels open what happens?

A

K+ diffuses out, making the inside of the cell more negative (hyperpolarization)

41
Q

increase in magnitude of the membrane potential

A

hyperpolarization

42
Q

what triggers depolarization?

A

opening other types of ion channels

43
Q

a reduction in the magnitude of the membrane potential

A

depolarization

44
Q

what is an example of depolarization?

A

occurs if gated Na+ channels open and Na+ diffuses into the cell

45
Q

changes in polarization where the magnitude of the change varies with the strength of the stimulus

A

graded potentials

46
Q

what are graded potentials NOT and what do they have an effect on?

A

they are not nerve signals that travel along axons and they have an effect on the generation of nerve signals

47
Q

if a depolorization shifts the membrane potential sufficiently what massive change in membrane voltage occurs?

A

action potential (not graded)

48
Q

what do action potentials have and what do they transmit over long distances?

A

they have a constant magnitude and they transmit signals

49
Q

why do action potentials arise?

A

because some ion channels are voltage-gated and open or close when the membrane potential passes a certain level

50
Q

what can an action potential be considered as?

A

a series of stages

51
Q

characteristics of an action potential at resting potential

A
  1. most voltage-gated sodium (Na+) and potassium (K+) channels are closed
52
Q

what happens second when the action potential is generated?

A
  1. voltage-gated Na+ channels open first and Na+ flows into the cell
53
Q

what happens third when the action potential is generated during the rising phase?

A
  1. the threshold is crossed and the membrane potential increases
54
Q

what happens fourth when the action potential is generated during the falling phase?

A
  1. voltage-gated Na+ channels become inactivated; voltage K+ channels open and K+ flows out
55
Q

what happens fifth when the action potential is generated during the undershoot?

A
  1. membrane permeability to K+ is at first higher than at rest, then voltage-gated K+ channels close an resting potential is restored
56
Q

what happens sixth when the action potential is generated during the refractory period?

A
  1. after an action potential, a second potential cannot be initiated
57
Q

what is the refractory period of an action potential a result of?

A

temporary inactivation of the Na+ channels

58
Q

at the site where the action potential is generated (usually the axon hillock) what depolorizes the neighboring region of the axon membrane?

A

an electrical current

59
Q

how do action potentials travel?

A

only in one direction toward the synaptic terminals

60
Q

what does inactivated Na+ channels behind the zone of depolarization prevent?

A

the action potential from traveling backwards

61
Q

what does the speed of an action potential increase with?

A

the axon’s diameter

62
Q

in vertebrates what are axons insulated by and what do they cause?

A

myelin sheath which causes an action potential’s speed to increase

63
Q

what are myelin sheaths made of?

A

glia- oligodendrocytes in the CNS and Schwana cells in the PNS

64
Q

where do neurons communicate with other cells?

A

at synapses

65
Q

what do electrical curren tflows go from one to another through electrical synapses?

A

through gap junctions

66
Q

what does a chemical neuron carry at chemical synapses?

A

information between neurons

67
Q

what are most synapses?

A

chemical synapses

68
Q

where does the presynaptic neuron synthesize and package the neurotransmitter?

A

in synaptic vesicles located in the synaptic terminal

69
Q

what does the action potential cause the release of?

A

the neurotransmitter

70
Q

where does the neurotransmitter diffuse across and what is it received by?

A

across the synaptic cleft and if received by the postsynaptic cell

71
Q

where does direct transmission involve the binding of neurotransmitters to?

A

ligand-gated ion channels

72
Q

where are the ligand-gated ion channels located?

A

in the postsynaptic cell

73
Q

what does neurotransmitter binding cause?

A

ion channels to open, generating a postsynaptic potential.

74
Q

two categories of postsynaptic potentials

A

1) excitatory postsynaptic potentials (EPSPs)

2) inhibitory postsynaptic potentials (IPSPs)

75
Q

depolarizations that bring the membrane potential toward threshold

A

excitatory postsnyaptic potential (EPSPs)

76
Q

hyperpolarizations that move membrane potential further from threshold

A

inhibitory postsynaptic potential (IPSPs)

77
Q

where do most neurons have many synapses on?

A

their dendrites and cell body

78
Q

what is a single EPSP usually too small to trigger?

A

an action potential in a postsynaptic neuron

79
Q

what occurs if two EPSPs are produced in rapid succession?

A

an effect called temporal summation occurs

80
Q

EPSPs produced nearly simultanously by different synapses on the same postsynaptic neuron add together

A

spatial summation

81
Q

what can the combination of EPSPs through a spatial and temporal summation trigger?

A

an action potential

82
Q

through summation, what can an IPSP counter?

A

the effect of an EPSP

83
Q

what does the summed effect of EPSP s and IPSPs determine?

A

whether an axon hillock will reach threshold and generate an action potential.

84
Q

in some synapses what does a neurotransmitter bind to?

A

a receptor that is metabotropic

85
Q

if a neurotransmitter binds to a receptor that is metabotropic what does movement of ions through a channel depend on?

A

one ore more metabolic steps

86
Q

what does binding of a neurotransmitter to a metabotropic receptor activate?

A

a signal transduction pathway in the postsynaptic cell involving a second messenger

87
Q

compared to ligand-gated channels what does the effects of the second messenger systems have?

A

a slower onset but lasts longer

88
Q

what may a single neurotransmitter bind specifically to?

A

more than a dozen different receptors

89
Q

when does receptor activation and postsynaptic response cease?

A

when neurotransmitters are cleared from the synaptic cleft

90
Q

what are neurotransmitters removed by? (3) (SIR)

A

1) simple diffusion
2) inactivation by enzymes
3) recapture into the presynaptic neuron

91
Q

a common neurotransmitter in vertebrates and invertebrates

A

acetycholine

92
Q

what is acetycholine involved in? (3) (MML)

A

1) muscle stimulation
2) memory formation
3) learning

93
Q

what disrupts acetycholine neurotransmission?

A

a number of toxins

94
Q

what do the toxins include that disrupts acetycholine neurotransmission?

A

1) nerve gas
2) sarin
3) botulism toxin produced by certain bacteria

95
Q

what is acetycholine just one of?

A

more than 100 known neurotransmitters

96
Q

what 4 classes does the remainder of neurotransmitters fall into? (ABNG)

A

1) amino acids
2) biogenic amines
3) neuropeptides
4) gases

97
Q

what do biogenic amines include? (3) (NDS)

A

1) norepinepherine
2) dopamine
3) serotonin

98
Q

mobilizes brain and body for action, fight or flight

A

norepinephrine

99
Q

reward motivated behavior

A

dopamine

100
Q

mood, appetite and sleep

A

serotonin

101
Q

where are biogenic amines active in?

A

the CNS and PNS

102
Q

what are local regulators in the PNS?

A

gases such as nitric oxide (NO) and carbon minoxide (CO)

103
Q

unlike most neurotransmitters what is not store in cytoplasmic vesicles but is synthesized on demand?

A

nitric oxide (NO)

104
Q

when is nitric oxide (NO) broken down?

A

within a few second of production

105
Q

although inhaling CO can be deadly what does the vertibrate body do?

A

synthesizes small amounts of it, some of which is used as a neurotransmitter

106
Q

where are action potentials formed only at?

A

nodes of Ranvier

107
Q

gaps in the myelin sheath where voltage-gated Na+ channels are found

A

nodes of Ranvier

108
Q

a process where action potentials are myelinated axons jump between the nodes of Ranvier.

A

saltatory conduction