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Neurotransmitters are released from the
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Synaptic terminals/knobs
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The brain and spinal cord comprise the
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Central nervous system
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The ion needed to initiate the release of acetylcholine into the synaptic cleft is
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Calcium.
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During saltatory conduction,action potentials move in all directions along an axon.action potentials occur between successive nodes along the length of the stimulated axon.local currents depolarize adjacent areas of membrane so that action potentials continue to form along the membrane.action potentials produce a local current that is strong enough to spread along the length of the axon.local potentials produce a continuous outward flow of potassium ions.
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Action potentials occur between successive nodes along the length of the stimulated axon.
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The all-or-none principle states that
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All stimuli great enough to bring the membrane to threshold will produce identical action potentials.
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Opening of sodium channels in the membrane of a neuron results in
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Depolarization
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At the normal resting potential of a typical neuron, its ion exchange pump
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Exchanges 3 intracellular sodium ions for 2 extracellular potassium ions
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If the sodium-potassium pumps in the cell membrane fail to function,the extracellular concentration of potassium ions will increase. the intracellular concentration of sodium ions will increase.the membrane will lose its capacity to generate action potentials.the inside of the membrane will have a resting potential that is more positive than normal.all of these will occur.
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All of these
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Tetradotoxin is a toxin that blocks the sodium channels from opening. What effect would this have on the function of neurons?
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The neurons would not be able to propagate action potentials
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The following is a series of events that occur at a typical cholinergic synapse. Place the events in the correct sequence.
1. Calcium ions enter the cytoplasm of the synaptic knob and ACh release occurs. 2. Arriving action potential depolarizes the synaptic knob and the presynaptic membrane. 3. Depolarization ends as ACh is broken down into acetate and choline by AChE. 4. ACh release ceases because calcium ions are removed from the cytoplasm of the synaptic knob. 5. The synaptic knob reabsorbs choline from the synaptic cleft and uses it to resynthesize ACh. 6. ACH diffuses across the synaptic cleft and binds to receptors on the postsynaptic membrane. 7. Sodium channels on postsynaptic surface are activated, producing a graded depolarization. The correct sequence of events is |
2, 1, 6, 7, 4, 3, 5.
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Voluntary control of skeletal muscles is provided by the
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Somatic nervous system
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Cells responsible for information processing and transfer are
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Neurons.
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The axon is connected to the soma or cell body at a region called the
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Hillock
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Branches that sometimes occur along the length of an axon are called
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Collaterals
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The site of intercellular communication between neurons is
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Synapse
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