Cholinesterase is an enzyme that breaks down acetylcholine in the synapse. What would be the result if acetylcholine was released at a synapse, but no cholinesterase was present? O a. The postsynaptic neuron would not be stimulated. Ob. A single nerve impulse would be generated in the postsynaptic neuron. Oc. The acetylcholine would diffuse more rapidly across the synaptic cleft. d. The postsynaptic neuron would remain in a constant state of depolarization.

Cholinesterase is an enzyme that breaks down acetylcholine in the synapse. What would be the result if acetylcholine was released at a synapse, but no cholinesterase was present? O a. The postsynaptic neuron would not be stimulated. Ob. A single nerve impulse would be generated in the postsynaptic neuron. Oc. The acetylcholine would diffuse more rapidly across the synaptic cleft. d. The postsynaptic neuron would remain in a constant state of depolarization.

Human Physiology: From Cells to Systems (MindTap Course List)

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter4: Principles Of Neural And Hormonal Communication

Section: Chapter Questions

Problem 4TAHL: Assume presynaptic excitatory neuron A terminates on a postsynaptic cell near the axon hillock and...

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Assume presynaptic excitatory neuron A terminates on a postsynaptic cell near the axon hillock and presynaptic excitatory neuron B terminates on the same postsynaptic cell on a dendrite located on the side of the cell body opposite the axon hillock. Explain why rapid firing of presynaptic neuron A could bring the postsynaptic neuron to threshold through temporal summation, thus initiating an action potential, whereas firing of presynaptic neuron B at the same frequency and the same magnitude of EPSPs may not bring the postsynaptic neuron to threshold.
If an excitatory synapse and inhibitory synapse generate postsynaptic potentials on the same neuron what can happen? a. The generated potentials will sum up to make a larger postsynaptic potential. b. Nothing will happen, because inhibitory neurons will not form synapses on the same neurons as excitatory neurons. c. The postsynaptic potential generated by the inhibitory synapse will shunt the excitatory synapse, leading to a reduction in the postsynaptic potential. d. None of the above
In the hippocampus, when glutatmate is released into the synaptic cleft, but the postsynaptic cell is NOT depolarized, there is only a small postsynaptic response. Why is this the case? A. Ca++ ions block the NMDA ion channel B. Mg++ ions block the NMDA ion channel C. Glutamate is an inhibitory amino acid neurotransmitter D. There are no NMDA receptors on the postsynaptic cell
Organophosphate pesticides inhibit the action of acetylcholinesterase. What effect does this have in the cell? Select one: a. It prevents synthesis of ACh in the presynaptic terminal causing less neurotransmitter release b. It prevents breakdown of ACh in the synapse causing increased activity at the postsynaptic cell c. It prevents reuptake of ACh into the presynaptic terminal causing increased activity at the postsynaptic cell d. It prevents binding of ACh on the postsynaptic cell causing less activity e. It prevents reuptake of ACh into the presynaptic terminal causing less neurotransmitter synthesis.
What statement about synapse activity is false? A.The input of sodium ions by AMPA receptors is triggered by glutamate binding to the same receptors.B.Calcium entering the dendritic spine during synaptic transmission activates proteins that can potentiate synapse.C.Depolarization of the membrane caused by the arrival of calcium ions makes it possible to eject sodium blocking NMDA receptors.D.Glutamate can be released by the pre-synaptic button following the arrival of an action potential via the axon.
Given the steps shown below, which of the following is the correct sequence for transmission at a chemical synapse? 1. neurotransmitter binds with receptor 2. sodium ions rush into neuron's cytoplasm 3. action potential depolarizes the presynaptic membrane 4. ion channel opens to allow particular ion to enter cell 5. synaptic vesicles release neurotransmitter into the synaptic cleft O 1, 2, 3, 4, 5 O 5, 1, 2, 4, 3 O 2, 3, 5, 4, 1 O4, 3, 1, 2, 5 O 3, 2, 5, 1, 4
The nerve impulses always travel in one direction from dendrites to axon terminals. What prevents an action potential from travelling backward? a. Hyperpolarization of the neuron makes the membrane more positive and prevents another action potential. b. After repolarization, the refractory period occurs, where the sodium ions are found outside the cell. c. After repolarization, the reversal of ions prevents another action potential as there would not be enough sodium ions outside the cell to rush in. d. The refractory period prevents another action potential by lowering the threshold potential.
An undisclosed drug (Drug A) is a drug that can block voltage-gated K+ channels when being introduced into the bloodstream. Explain the effects of Drug A on the action potentials produced by a neuron. If Drug A could be applied selectively to a presynaptic neuron that releases an excitatory neurotransmitter, analyse how would it alter the synaptic effect of the neurotransmitter on the presynaptic cell. Remark: The word count limit (250 words only), no less than 100 words
The axon hillock of a neuron reaches the threshold of excitation and the membrane potential becomes completely reversed. Then, suddenly, the membrane potential begins to return to resting membrane potential. What is the event that triggers this return to resting potential? A. Na+ channels close in a voltage-dependent manner B. Na+ channels close in a time-dependent manner C. Na+ channels close in a chemically-dependent manner D. Na+ channels open in a voltage-dependent manner
Arrange the events that occur during synaptic transmission. Use letters A-F to denote the correct sequence. Use the diagram on the right as a clue. Example: SENDING NEURON vescJes B 1. lon channel opens Synepto SYNAPSE 1. lon channel opens 2. Neurotransmitter is released into synaptic cleft SYNAPTIC CLEFT RECEMNG NEURC4 Neurotransmitter To us 3. Vesicle fuses with plasma membrane Jon chzn nels Neurotrensmitter Feptor Neurotrensmitter broen down zna selaesed 4. Neurotransmitter binds to receptor tOnS 5. Action potential arrives 辦 6. lon channel closes
I have stimulated a neuron with dopamine for a second followed by treating it with cocaine and calcium chelating agent (which chelates out all calcium from the system making them unavailable for function), what will be the effect of such impulse on generating an action potential in the post-synaptic neuron? Will it be different if I pretreat the set of nerve cells with cocaine and calcium chelating agent followed by stimulating the neuron with dopamine? Justify your answer with proper reasoning in brief.
Which of the following neuronal changes is associated with short term synaptic strength? O a. Changes in the size of neural spines o b. Changes in the shape of neural spines с. Increased production of neurotransmitter vesicles in the presynaptic cell o d. Increased buildup of Ca²+ in the terminal knob of the presynaptic axon О е. Increased expression of postsynaptic neurotransmitter receptors