Chapter 7 Pt. 2 Flashcards
The neuron membrane is specialized for ____________
communication
What are nerve impulses or action potentials?
an electrochemical signal caused by sodium ions (NA+) and potassium ions (K+) crossing the neuron’s membrane to enter and leave the cell
What are ion channels?
pores in the membrane that are able to pass through without using cellular energy
True or False: sodium channels allow the passage of ONLY sodium ions, and potassium channels allow ONLY potassium ions
True
What are sodium-potassium pumps?
special proteins in the cell membrane that actively transport sodium and potassium ions across the membrane
sodium-potassium pumps se cellular energy in the form of _____
ATP
Each sodium-potassium pump ejects __ sodium ions form within the cell while bringing in __ potassium ions
3
2
Each sodium-potassium pump ejects 3 _______ ions form within the cell while bringing in 2 _________ ions
sodium
potassium
What is resting potential?
keeping the inside surface more negative than the outside one
a neuron that is not transmitting an action potential is known as ______
resting
What is an action potential?
nerve impulse; a sudden reversal in the charge difference across the membrane, followed by the restoration of the original charge difference
What is the process of action potential?
1) sodium ions (Na+) enter the axon via depolarization
2) potassium (K+) ions leave the axon via repolarization
What is the difference between depolarization and repolarization?
depolarization-reduction of the change difference across the membrane
repolarization- restoration of the charge difference across the membrane
What is refractory period?
immediately after an action potential occurs, the neuron cannot be stimulated again for a brief instant
_________ _______ is the reason that nerve impulses cannot reverse and go backward toward the cell body
refractory period
Increasing the strength of a ________ will increase the _________ of impulses
stimulus
frequency
Once initiated an action potential sweeps to the end of the _____ without diminishing in ________
axon
strength
What is a neurotransmitter?
the chemical released from the axon’s tip
____________ diffuse across the gap and conveys the message to the adjacent cell
Neurotransmitters
What is a synapse?
the junction between a neuron and another cell
What is a synaptic cleft?
the gap between the cells
What is a synaptic knob?
a small bulblike swelling at the end of each branch
What is the difference between a presynaptic neuron and a postsynaptic neuron?
presynaptic neuron-the neuron sending the message
postsynaptic neuron-the neuron receiving the message
The process of releasing neurotransmitters and opening ion channels:
1)
2) synaptic knobs release packets of neurotransmitter into the synaptic cleft
3) neurotransmitter diffuses across the synaptic cleft
4) neurotransmitter binds with receptors on the membrane of the postsynaptic neuron
5) when a neurotransmitter binds to its receptor, an ion channel is opened
6) sodium ions enter the postsynaptic neuron, causing depolarization and possible action potential
1) the nerve impulse reaches the axon ending of the presynaptic neuron
The process of releasing neurotransmitters and opening ion channels:
1) the nerve impulse reaches the axon ending of the presynaptic neuron
2)
3) neurotransmitter diffuses across the synaptic cleft
4) neurotransmitter binds with receptors on the membrane of the postsynaptic neuron
5) when a neurotransmitter binds to its receptor, an ion channel is opened
6) sodium ions enter the postsynaptic neuron, causing depolarization and possible action potential
2) synaptic knobs release packets of neurotransmitter into the synaptic cleft
The process of releasing neurotransmitters and opening ion channels:
1) the nerve impulse reaches the axon ending of the presynaptic neuron
2) synaptic knobs release packets of neurotransmitter into the synaptic cleft
3)
4) neurotransmitter binds with receptors on the membrane of the postsynaptic neuron
5) when a neurotransmitter binds to its receptor, an ion channel is opened
6) sodium ions enter the postsynaptic neuron, causing depolarization and possible action potential
3) neurotransmitter diffuses across the synaptic cleft
The process of releasing neurotransmitters and opening ion channels:
1) the nerve impulse reaches the axon ending of the presynaptic neuron
2) synaptic knobs release packets of neurotransmitter into the synaptic cleft
3) neurotransmitter diffuses across the synaptic cleft
4)
5) when a neurotransmitter binds to its receptor, an ion channel is opened
6) sodium ions enter the postsynaptic neuron, causing depolarization and possible action potential
4) neurotransmitter binds with receptors on the membrane of the postsynaptic neuron
The process of releasing neurotransmitters and opening ion channels:
1) the nerve impulse reaches the axon ending of the presynaptic neuron
2) synaptic knobs release packets of neurotransmitter into the synaptic cleft
3) neurotransmitter diffuses across the synaptic cleft
4) neurotransmitter binds with receptors on the membrane of the postsynaptic neuron
5)
6) sodium ions enter the postsynaptic neuron, causing depolarization and possible action potential
5) when a neurotransmitter binds to its receptor, an ion channel is opened
The process of releasing neurotransmitters and opening ion channels:
1) the nerve impulse reaches the axon ending of the presynaptic neuron
2) synaptic knobs release packets of neurotransmitter into the synaptic cleft
3) neurotransmitter diffuses across the synaptic cleft
4) neurotransmitter binds with receptors on the membrane of the postsynaptic neuron
5) when a neurotransmitter binds to its receptor, an ion channel is opened
6)
6) sodium ions enter the postsynaptic neuron, causing depolarization and possible action potential
__________ is the combined effects of excitatory and inhibitory effects on a neuron at any given moment determines whether an ______ _________ is generated
Summation
action potential
Summation is the combined effects of ________ and _________ effects on a neuron at any given moment determines whether an action potential is generated
excitatory
inhibitory
True or False: After being released into a synapse, neurotransmitters are quickly removed, so their effects are temporary
True
Depending on the neurotransmitter, disposal is accomplished in one of what 2 ways?
1) enzymes can deactivate a neurotransmitter
2) the neurotransmitter may be actively pumped back into the presynaptic knob
____________, __________, and ____________ are neurotransmitters used in both peripheral and central nervous system.
Acetylcholine
epinephrine
norepinephrine
Acetylcholine, epinephrine, and norepinephrine are neurotransmitters used in both _________ and ______ _______ system.
peripheral
central nervous
Both ___________ and ____________ have either excitatory or inhibitory effects
Acetylcholine
norepinephrine
Both Acetylcholine and norepinephrine have either ________ or ________ effects
excitatory
inhibitory
Which neurotransmitter is this: stimulates most organs but inhibits certain others
norepinephrine
Which neurotransmitter is this: will have the opposite of Acetylcholine
norepinephrine
Which neurotransmitter is this: mood regulation
norepinephrine
Which neurotransmitter is this: pleasure system
norepinephrine
Which neurotransmitter is this: arousal
norepinephrine
Which neurotransmitter is this: essential in hunger, thirst, and sex drive
norepinephrine
Which neurotransmitter is this: triggers contraction of voluntary (skeletal) muscle
Acetylcholine
Which neurotransmitter is this: promote a generalized feeling of well-being
serotonin
Which neurotransmitter is this: helps regulate emotions
dopamine
Which neurotransmitter is this: used in pathways that control complex movements
dopamine
What is myasthenia gravis?
an autoimmune disease in which the body’s defense mechanisms attack the acetylcholine receptors at neuromuscular junctions
Postsynaptic cells integrate _________ and ________ input from many cells
excitatory
inhibitory
