Peripheral Nervous System And Synaptic Pharmacology 3: The Synapse
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Lecture 3
Questions and Answers
- 1.
Neuron-neuron and neuron-target organ communication occurs at the synapse.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because synapses are the junctions between neurons where communication occurs. Neurons transmit signals to other neurons or target organs through these synapses. At the synapse, electrical signals from the transmitting neuron are converted into chemical signals, which then travel across the synapse and are received by the next neuron or target organ. This communication is crucial for the functioning of the nervous system and the coordination of various physiological processes.Rate this question:
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- 2.
In the human nervous system there are around 10^14 synapses.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The human nervous system contains an incredibly large number of synapses, estimated to be around 10^14. Synapses are the connections between neurons that allow for communication and transmission of signals. This vast number of synapses is crucial for the complex functioning of the nervous system, enabling the processing and integration of information throughout the body.Rate this question:
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- 3.
Excitatory synapses cause a repolarisation of a neuronal membrane potential.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
E. synapses cause depolarisation of a neuronal membrane potential.Rate this question:
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- 4.
Some synapses are inhibitory, in that they cause hyperpolarisation of the neuronal membrane potential.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Some synapses are inhibitory, meaning that when they are activated, they actually cause the neuronal membrane potential to become more negative, a process known as hyperpolarization. This inhibitory effect reduces the likelihood of the neuron firing an action potential, thus decreasing neuronal activity. Therefore, the statement that some synapses cause hyperpolarization of the neuronal membrane potential is true.Rate this question:
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- 5.
A convergent pathway is where one synapse communicates with many neurons.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
A divergent pathway is one where a single synapse communicates with many neurons.Rate this question:
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- 6.
Specialised synapses are in certain tissues.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Specialized synapses refer to synapses that are specifically adapted to carry out specific functions in certain tissues. These synapses have unique characteristics and structures that enable them to efficiently transmit signals between neurons. Therefore, the statement "Specialized synapses are in certain tissues" is true, as these synapses are indeed found in specific tissues where their specialized functions are required.Rate this question:
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- 7.
Chemical synapses...
- A.
Communicate via gap junctions.
- B.
Communicate via neurotransmitters.
Correct Answer
B. Communicate via neurotransmitters.Explanation
Chemical synapses are specialized junctions between neurons where communication occurs through the release and binding of neurotransmitters. Neurotransmitters are chemical messengers that transmit signals across the synapse from the presynaptic neuron to the postsynaptic neuron. This process allows for the transmission of information and coordination of neuronal activity in the nervous system. Gap junctions, on the other hand, are direct channels between cells that allow for the passage of ions and small molecules, but they are not involved in the transmission of signals between neurons.Rate this question:
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- 8.
Electrical synapses...
- A.
Communicate via gap junctions.
- B.
Communicate via neurotransmitters.
Correct Answer
A. Communicate via gap junctions.Explanation
Electrical synapses refer to the direct transfer of electrical signals between cells through specialized channels called gap junctions. These gap junctions allow for the passage of ions and small molecules, enabling the rapid and synchronized transmission of electrical impulses. In contrast, communication via neurotransmitters involves the release and binding of chemical messengers to transmit signals between neurons. Therefore, the correct answer is that electrical synapses communicate via gap junctions.Rate this question:
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- 9.
Neurotransmitter is only removed by being broken down by enzymes in the synaptic cleft.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Neurotransmitter may also be removed from the synaptic cleft via reabsorption into the synapse.Rate this question:
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- 10.
The first stage of synaptic transmission of a chemical signal across a synapse is...
- A.
Neurotransmitter is released by exocytosis into the synaptic cleft
- B.
Ca2+ enters the synaptic knob/presynaptic terminal
- C.
An action potential is propagated to the terminal of a presynaptic membrane
Correct Answer
C. An action potential is propagated to the terminal of a presynaptic membraneExplanation
The first stage of synaptic transmission is the propagation of an action potential to the terminal of a presynaptic membrane. This action potential is an electrical signal that travels down the axon of the neuron to reach the terminal. Once the action potential reaches the terminal, it triggers the release of neurotransmitters by exocytosis into the synaptic cleft. The neurotransmitters then bind to receptors on the postsynaptic membrane, initiating the transmission of the chemical signal across the synapse. The entry of Ca2+ into the synaptic knob is an important step in the release of neurotransmitters, but it occurs after the propagation of the action potential.Rate this question:
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- 11.
The second stage of synaptic transmission of a chemical signal across a synapse is...
- A.
Neurotransmitter is released by exocytosis into the synaptic cleft
- B.
Ca2+ enters the synaptic knob/presynaptic terminal
- C.
An action potential is propagated to the terminal of a presynaptic membrane
Correct Answer
B. Ca2+ enters the synaptic knob/presynaptic terminalExplanation
In the second stage of synaptic transmission, Ca2+ enters the synaptic knob/presynaptic terminal. This is an important step because the influx of Ca2+ triggers the release of neurotransmitters by exocytosis into the synaptic cleft. This release of neurotransmitters allows for the chemical signal to be transmitted from the presynaptic neuron to the postsynaptic neuron. The entry of Ca2+ is necessary for the proper functioning of synaptic transmission and plays a crucial role in the communication between neurons.Rate this question:
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- 12.
The third stage of synaptic transmission of a chemical signal across a synapse is...
- A.
Neurotransmitter is released by exocytosis into the synaptic cleft
- B.
Ca2+ enters the synaptic knob/presynaptic terminal
- C.
An action potential is propagated to the terminal of a presynaptic membrane
Correct Answer
A. Neurotransmitter is released by exocytosis into the synaptic cleftExplanation
The third stage of synaptic transmission involves the release of neurotransmitter molecules into the synaptic cleft. This release is achieved through exocytosis, a process by which the neurotransmitter-containing vesicles fuse with the presynaptic membrane and release their contents into the synapse. This allows the neurotransmitter to diffuse across the synaptic cleft and bind to receptors on the postsynaptic membrane, initiating the transmission of the chemical signal to the next neuron or target cell.Rate this question:
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- 13.
The fourth stage of synaptic transmission of a chemical signal across a synapse is...
- A.
Specific ion channels open in the subsynaptic membrane
- B.
Neurotransmitter is removed from the synaptic cleft
- C.
Neurotransmitter binds to specific sites on the postsynaptic neuron
Correct Answer
C. Neurotransmitter binds to specific sites on the postsynaptic neuronExplanation
In the fourth stage of synaptic transmission, the neurotransmitter binds to specific sites on the postsynaptic neuron. This binding allows the neurotransmitter to transmit its signal to the postsynaptic neuron, initiating a response. The binding of the neurotransmitter to these specific sites triggers a series of biochemical events within the postsynaptic neuron, ultimately leading to the transmission of the signal. This stage is crucial for the communication between neurons and the transmission of information in the nervous system.Rate this question:
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- 14.
The fifth stage of synaptic transmission of a chemical signal across a synapse is...
- A.
Specific ion channels open in the subsynaptic membrane
- B.
Neurotransmitter is removed from the synaptic cleft
- C.
Neurotransmitter binds to specific sites on the postsynaptic neuron
Correct Answer
A. Specific ion channels open in the subsynaptic membraneExplanation
In the fifth stage of synaptic transmission, specific ion channels open in the subsynaptic membrane. This allows for the flow of ions into or out of the postsynaptic neuron, which generates an electrical signal. This signal is essential for the transmission of the chemical signal across the synapse. The opening of specific ion channels is a crucial step in the process of synaptic transmission, as it enables the propagation of the signal from the presynaptic neuron to the postsynaptic neuron.Rate this question:
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- 15.
The sixth stage of synaptic transmission of a chemical signal across a synapse is...
- A.
Specific ion channels open in the subsynaptic membrane
- B.
Neurotransmitter is removed from the synaptic cleft
- C.
Neurotransmitter binds to specific sites on the postsynaptic neuron
Correct Answer
B. Neurotransmitter is removed from the synaptic cleftExplanation
In the sixth stage of synaptic transmission, the neurotransmitter is removed from the synaptic cleft. This is an important step to ensure that the signal is not continuously transmitted and that the synapse can be ready for the next signal. The removal of neurotransmitter can occur through various mechanisms such as reuptake by the presynaptic neuron or enzymatic degradation. By removing the neurotransmitter, the synaptic cleft is cleared, allowing for the termination of the signal and preventing overstimulation of the postsynaptic neuron.Rate this question:
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- 16.
The neuromuscular junction is a specialised synapse between a beta-motor neuron and a skeletal muscle fibre at the motor end plate
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
*alpha-motor neuronRate this question:
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- 17.
The neuromuscular junction is...
- A.
The peripheral synapse of the somatic efferent nervous system
- B.
The peripheral synapse of the autonomic afferent nervous system
- C.
The peripheral synapse of the somatic afferent nervous system
- D.
The peripheral synapse of the autonomic efferent nervous system
Correct Answer
A. The peripHeral synapse of the somatic efferent nervous systemExplanation
The neuromuscular junction is the synapse between a motor neuron and a muscle fiber. It is responsible for transmitting signals from the motor neuron to the muscle fiber, allowing for muscle contraction. This process is part of the somatic efferent nervous system, which controls voluntary muscle movements. Therefore, the correct answer is "The peripheral synapse of the somatic efferent nervous system."Rate this question:
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- 18.
The alpha-motor neuron synapses with several different muscle fibres (divergent pathway)
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because the alpha-motor neuron, which is responsible for initiating muscle contractions, can synapse with multiple muscle fibers. This allows for the activation of a group of muscle fibers simultaneously, resulting in coordinated and efficient muscle contractions. This divergent pathway ensures that the alpha-motor neuron can control and coordinate the movements of multiple muscle fibers at once.Rate this question:
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- 19.
The alpha-motor neuron...
- A.
Originates from the CNS with its cell body in the grey matter of the spinal cord or brain stem
- B.
Originates from the PNS with its cell body in the grey matter of the spinal cord or brain stem
- C.
Originates from the PNS with its cell body recieving a signal from an interneuron
- D.
Originates from the CNS with its cell body recieving its signal from another efferent neuron
Correct Answer
A. Originates from the CNS with its cell body in the grey matter of the spinal cord or brain stemExplanation
The alpha-motor neuron originates from the central nervous system (CNS) with its cell body located in the grey matter of the spinal cord or brain stem. This means that the neuron is part of the CNS and its cell body is situated in the regions of the spinal cord or brain stem where the grey matter is present.Rate this question:
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- 20.
The neurotransmitter in a neuromuscular junction is...
- A.
Ethanol
- B.
Dopamine
- C.
Noradrenaline
- D.
Acetylcholine
Correct Answer
D. AcetylcholineExplanation
Acetylcholine is the correct answer because it is the primary neurotransmitter involved in transmitting signals from motor neurons to muscle fibers in the neuromuscular junction. It binds to receptors on the muscle fiber, causing muscle contraction. Ethanol, dopamine, and noradrenaline are not neurotransmitters involved in the neuromuscular junction.Rate this question:
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Nov 10, 2023Quiz Edited by
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Oct 02, 2011Quiz Created by
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