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Anatomy > Nervous Tissue and Physiology II: Lecture 19 > Flashcards

Nervous Tissue and Physiology II: Lecture 19 Flashcards

1
Q

voltage

A

measure of potential energy by separate electrical charges

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2
Q

current

A

flow of charge from one point to another

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3
Q

resistance

A

hindrance to flow of electrical charge

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4
Q

relationship between current, voltage, and resistance

A

greater voltage = greater current
less resistance = greater current

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5
Q

Na+/K+ pump

A

3 Na+ out, 2 K+ in
more positive ions moving out than in on average

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6
Q

K/Na leak channels

A

both Na+ and K+ diffuse through leak channels down concentration gradients
many more K leak channels than Na leak channels

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7
Q

neuron resting membrane potential

A

-70 mV
difference in charge between inside and outside of neuron at rest

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8
Q

polarized neuron membrane

A

outside pos charged
inside neg charged

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9
Q

neuron cell cytosol ionic composition

A

lower conc of Na+
higher conc of K+

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10
Q

neuron extracellular fluid ionic compostion

A

cations balanced out by Cl- ions

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11
Q

neural plasma membrane permeability

A

K+ diffuse out of the cell more easily than Na+
allows internal portion of the cell to become more negative

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12
Q

graded potential

A

incoming signals over a short distance

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13
Q

action potential

A

long distance signaling

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14
Q

depolarization

A

decrease in membrane potential
inside becomes less negative

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15
Q

hyperpolarization

A

increase in membrane potential
inside becomes more negative

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16
Q

graded depolarization

A

sodium ions (+) enter the cell

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17
Q

graded hyper-polarization

A

chloride ions (-) enter the cell

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18
Q

basis of neural signaling

A

converting local potentials to action potentials is the basis of neural signaling

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19
Q

graded potential v action potential

A

graded: magnitude varies with signal strength
action: do not decay with distance, excitable membranes

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20
Q

action potential generation

A

resting state: all gated Na+ and K+ channels closed
depolarization: Na+ channels open, reach threshold level, self generating
repolarization: Na+ channels are inactivating, K+ channels open
hyperpolarization: K+ channels remain open and Na+ channels reset

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21
Q

action potential threshold

A

must reach -55 mV
all or nothing; reached and does not happen

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22
Q

propagation

A

spreads from point of origin

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23
Q

frequency of AP

A

frequency of AP determines the stimulus intensity

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24
Q

AP refractory period

A

neurons cannot respond until the Na+ channels reset
elevated threshold level

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25
saltatory conduction
myelinated axons, jumps from node to node
26
continuous conduction
unmyelinated, every section of axolemma must propagate action potential, slows conduction speed
27
conduction velocity facors
axon diameter, degree of myelination
28
fiber group a
largest diameter thick myelin sheath somatic sensory and motor fibers 300+ mph
29
fiber group b
intermediate diameter light myelin sheath ANS 30 mph
30
fiber group c
smallest diameter non-myelinated ANS 2 mph
31
AP trigger zone
axon hillock
32
AP summary
1. large concentration of voltage-gated Na+ channels in axon hillock 2. local potential arrives, voltage-gated Na+ channels open and start pos feedback loop, massive depolarization 3. Na channels inactivated, K channels activated 4. Na channels return to resting state, K channels slowly close 5. after brief hyperpolarization, both channels return to resting state
33
synapses
junction that mediates information transfer from one neuron to the next
34
presynaptic neuron
transmitting the signal
35
postsynaptic neuron
receiving the signal
36
axodendritic neurons
synapses between axon endings and dendrites
37
axosomatic synapses
synapses between cell body and axon
38
synaptic transmission
transfer of chemical or electrical signals between neurons at synapse fundamental process for most functions of nervous system
39
chemical synapses
make up majority of synapses in nervous system, allow for release of neurotransmitters
40
synaptic vesicles
filled with chemical messengers transmit signals from presynaptic to postsynaptic neurons at chemical synapse
41
synaptic cleft
small ECF-filled space separates presynaptic and postsynaptic neurons in chemical synapses prevents direct stimulation
42
axon terminal
contain synaptic vesicles containing neurotransmitter
43
receptor region
located on cell body or dendrites
44
reuptake
taken in by astrocytes of presynaptic terminal
45
degradation
broken down by enzymes
46
diffusion
moves away from receptors
47
synapse delay
signal must wait for chemicals to diffuse slowest/ rate-limited step
48
chemical synapse info transfer summary
-action potential arrives at terminal -voltage-gated Ca2+ channels open and calcium enters axon terminal -Ca2+ entry causes release of neurotransmitter via exocytosis -neurotransmitter diffuses across synaptic cleft and binds to receptors -binding opens ion channels creating a graded potential (local or action) -neurotransmitter effects terminated -delay
49
excitatory synapses
binding of neurotransmitter opens chemically gated ion channels excitatory postsynaptic potentials occur
50
inhibitory synapses
reduces the ability to produce an AP -allows Cl- to move into cell inhibitory postsynaptic potentials
51
postsynaptic potentials
local potentials in membranes of postsynaptic neuron excitatory- membrane potential of postsynaptic neuron moves closer to threshold (EPSP) inhibitory- membrane potential of postsynaptic neuron moves farther away from threshold (IPSP)
52
integration
summations, synaptic potentiation, presynaptic inhibition
53
summation
temporal: presynaptic neurons send impulses rapidly spatial: large stimulation event facilitated: partially depolarized, more easily excited
54
synaptic potentiation
-repeated or continuous use enhances synapse's ability to be excited
55
presynaptic inhibition
-one neuron can inhibit the impulse of another
56
neurotransmitter
-chemical substance produced by the neurons -causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other target structure
57
neurotransmitter function
excitatory- depolarization inhibitory- hyperpolarization direct-open ion channels indirect- secondary messenger systems
58
neurotransmitter receptors
channel-linked: ligand-gated ion channels G-protein linked receptors: indirect and slow, activate secondary messenger systems
59
catecholamines
-dopamine -norepinephrine -epinephrine
60
indolamines
-serotonin -histamine
61
amino acids
-glutamate -aspartate -glycine -gamma aminobutyric acid (GABA)
62
peptides
neuropeptides -substance P -endorphins -gut-brain peptides
63
purines
-ATP -adenosine
64
gases and lipids
-gasotransmitters -endocannabinoids -tetrahydrocannabinol (THC)
65
acetylcholine
in neuromuscular junction within brain and spinal cord and within autonomic nervous system
66
norepinephrine
(noradrenalin) influences heart rate, blood pressure, and digestion; in CNS regulates sleep/wake cycle, attention, and feeding behaviors
67
epinephrine
(adrenalin) similar functions as norepinephrine, more widely used as hormone by endocrine system
68
dopamine
movement coordination, emotion and motivation
69
serotonin
mood regulation, emotions, attention, feeding behaviors
70
histamine
regulation of arousal and attention
71
glutamate
most important excitatory neurotransmitter in CNS; opens channels that allow flow of both Na and Cl ions, generate EPSPs in postsynaptic neuron
72
Glycine/GABA
major inhibitory, induce IPSPs; hyperpolarize axolemma
73
substance P
pain and temperature
74
opioids
include endorphins, enkephalins, and dynorphins; all elicit pain relief; nervous system depressants
75
neuropeptide Y
feeding behaviors; may mediate hunger or feeling full
76
black widow neurotoxin
toxin causes massive release of neurotransmitter; causes repetitive stimulation of postsynaptic neuron symptoms: muscle hyperexcitability, sweating, nausea and vomiting, and difficulty breathing
77
bark scorpion neurotoxin
most lethal; venom prevents postsynaptic sodium channels from closing; membrane remains polarized; continues to fire action potentials
78
neuronal pools
functioning groups of neurons stimuli highest at center of pool
79
serial processing
step by step transmission of impulse reflexes/reflex arcs
80
parallel processing
segregated input simultaneous input to different pathways
81
types of circuits
patterns of connection divergent, convergent, reverberating, parallel after-discharge

Anatomy (23 decks)

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