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Questions and Answers
What can activate chemo receptors in the gastrointestinal nervous system?
What can activate chemo receptors in the gastrointestinal nervous system?
What can stimulation of chemo receptors lead to in the gastrointestinal nervous system?
What can stimulation of chemo receptors lead to in the gastrointestinal nervous system?
What type of secretions can specific glands release in the gastrointestinal nervous system?
What type of secretions can specific glands release in the gastrointestinal nervous system?
What can fatty chyme stimulate in the gastrointestinal nervous system?
What can fatty chyme stimulate in the gastrointestinal nervous system?
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What can be stimulated to release cholecystokinin (CCK) in the gastrointestinal nervous system?
What can be stimulated to release cholecystokinin (CCK) in the gastrointestinal nervous system?
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What can glucose stimulate in the gastrointestinal nervous system?
What can glucose stimulate in the gastrointestinal nervous system?
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What can autonomously respond to chemical and stretch sensations in the gastrointestinal nervous system?
What can autonomously respond to chemical and stretch sensations in the gastrointestinal nervous system?
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What does the sympathetic nervous system oppose in the gastrointestinal tract?
What does the sympathetic nervous system oppose in the gastrointestinal tract?
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Where is the myenteric plexus located?
Where is the myenteric plexus located?
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What are the components of the enteric nervous system?
What are the components of the enteric nervous system?
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What is the function of the myenteric plexus?
What is the function of the myenteric plexus?
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What can influence the activity of the enteric nervous system?
What can influence the activity of the enteric nervous system?
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What are the components of the alimentary canal?
What are the components of the alimentary canal?
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What is the role of the submucosal plexus?
What is the role of the submucosal plexus?
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What do chemo receptors in the alimentary canal respond to?
What do chemo receptors in the alimentary canal respond to?
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What can the enteric nervous system be stimulated by to regulate GI motility?
What can the enteric nervous system be stimulated by to regulate GI motility?
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What is the role of short reflex arcs and long reflex arcs?
What is the role of short reflex arcs and long reflex arcs?
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What does the myenteric plexus release in response to stretch receptors?
What does the myenteric plexus release in response to stretch receptors?
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What is the histological composition of the alimentary canal?
What is the histological composition of the alimentary canal?
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What is the primary function of the reuptake protein mentioned in the text?
What is the primary function of the reuptake protein mentioned in the text?
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What is the specific name of the reuptake protein for serotonin mentioned in the text?
What is the specific name of the reuptake protein for serotonin mentioned in the text?
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What is the consequence of inhibiting the reuptake protein for serotonin?
What is the consequence of inhibiting the reuptake protein for serotonin?
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What is the purpose of incorporating neurotransmitters back into vesicles in the axon terminal?
What is the purpose of incorporating neurotransmitters back into vesicles in the axon terminal?
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Where does protein synthesis take place in neurons?
Where does protein synthesis take place in neurons?
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What is responsible for releasing neurotransmitters to communicate with other neurons or target cells?
What is responsible for releasing neurotransmitters to communicate with other neurons or target cells?
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Which part of the neuron is involved in the transmission of electrical signals generated by the cell body to the axon terminal?
Which part of the neuron is involved in the transmission of electrical signals generated by the cell body to the axon terminal?
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What determines whether an action potential will be initiated and propagated along the axon?
What determines whether an action potential will be initiated and propagated along the axon?
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Where are synthesized proteins, such as neurotransmitters, packaged into vesicles?
Where are synthesized proteins, such as neurotransmitters, packaged into vesicles?
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What is the role of the dendrites in neuronal function?
What is the role of the dendrites in neuronal function?
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What is the function of the axon in a neuron?
What is the function of the axon in a neuron?
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Where does the process of DNA transcription occur in neurons?
Where does the process of DNA transcription occur in neurons?
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What is the main function of the axon terminal in a neuron?
What is the main function of the axon terminal in a neuron?
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Where are synaptic vesicles containing neurotransmitters released from?
Where are synaptic vesicles containing neurotransmitters released from?
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What is the role of the cell bodies in a neuron?
What is the role of the cell bodies in a neuron?
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What is the function of dendrites in a neuron?
What is the function of dendrites in a neuron?
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What determines whether an action potential will be initiated and propagated along the axon in a neuron?
What determines whether an action potential will be initiated and propagated along the axon in a neuron?
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What is the role of EPSPs in a neuron?
What is the role of EPSPs in a neuron?
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What is the function of the axon terminal in a neuron?
What is the function of the axon terminal in a neuron?
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What is the role of IPSPs in a neuron?
What is the role of IPSPs in a neuron?
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What is the location where the cell body narrows and goes into the axon called?
What is the location where the cell body narrows and goes into the axon called?
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What are graded potentials involved in?
What are graded potentials involved in?
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What is the elongated portion between the cell body and axon terminal called?
What is the elongated portion between the cell body and axon terminal called?
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What are EPSPs and IPSPs collectively known as?
What are EPSPs and IPSPs collectively known as?
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What do dendrites have that are involved in the formation of EPSPs and IPSPs?
What do dendrites have that are involved in the formation of EPSPs and IPSPs?
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What is the circular structure with various components inside called in a neuron?
What is the circular structure with various components inside called in a neuron?
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What do IPSPs do to the cell's charge?
What do IPSPs do to the cell's charge?
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What is the bulbous structure at the end of the neuron called?
What is the bulbous structure at the end of the neuron called?
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What is the primary function of the axon?
What is the primary function of the axon?
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Which motor protein is responsible for anterograde axonal transport?
Which motor protein is responsible for anterograde axonal transport?
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What does retrograde axonal transport involve?
What does retrograde axonal transport involve?
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What is the role of dynein in axonal transport?
What is the role of dynein in axonal transport?
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What is the function of kinesin in axonal transport?
What is the function of kinesin in axonal transport?
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What do action potentials involve?
What do action potentials involve?
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What is the involvement of dynein in retrograde axonal transport?
What is the involvement of dynein in retrograde axonal transport?
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What substances does kinesin transport from the cell body to the axon terminal?
What substances does kinesin transport from the cell body to the axon terminal?
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What is the clinical relevance of axonal transport and the function of the axon?
What is the clinical relevance of axonal transport and the function of the axon?
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How does the axon conduct action potentials?
How does the axon conduct action potentials?
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What substances does dynein transport from the axon terminal to the cell body?
What substances does dynein transport from the axon terminal to the cell body?
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What are microtubules in the axon responsible for carrying?
What are microtubules in the axon responsible for carrying?
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What is the role of dyneins in axonal transport?
What is the role of dyneins in axonal transport?
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What can pathogens like polio and rabies viruses do in relation to axonal transport?
What can pathogens like polio and rabies viruses do in relation to axonal transport?
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What stimulates voltage-gated calcium channels in the axon terminal?
What stimulates voltage-gated calcium channels in the axon terminal?
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What is the function of snare proteins in the axon terminal?
What is the function of snare proteins in the axon terminal?
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What occurs through re-uptake and degradation in the synapse?
What occurs through re-uptake and degradation in the synapse?
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What is the crucial role of the axon terminal?
What is the crucial role of the axon terminal?
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Why is understanding axonal transport and axon terminal function essential?
Why is understanding axonal transport and axon terminal function essential?
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What is the consequence of inhibiting the reuptake protein for serotonin?
What is the consequence of inhibiting the reuptake protein for serotonin?
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Where does the process of DNA transcription occur in neurons?
Where does the process of DNA transcription occur in neurons?
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What is the primary function of the axon?
What is the primary function of the axon?
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What is the location where the cell body narrows and goes into the axon called?
What is the location where the cell body narrows and goes into the axon called?
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What is the elongated portion between the cell body and axon terminal called?
What is the elongated portion between the cell body and axon terminal called?
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Which motor proteins are involved in axonal transport?
Which motor proteins are involved in axonal transport?
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What is the role of dyneins in axonal transport?
What is the role of dyneins in axonal transport?
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What stimulates the release of neurotransmitters into the synapse from the axon terminal?
What stimulates the release of neurotransmitters into the synapse from the axon terminal?
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What is the function of v-snares and t-snares in the axon terminal?
What is the function of v-snares and t-snares in the axon terminal?
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What occurs through re-uptake or degradation of neurotransmitters in the synapse?
What occurs through re-uptake or degradation of neurotransmitters in the synapse?
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What is the primary role of the axon terminal in a neuron?
What is the primary role of the axon terminal in a neuron?
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What is essential for comprehending the mechanisms of nerve signaling and the pathogenesis of certain viral infections?
What is essential for comprehending the mechanisms of nerve signaling and the pathogenesis of certain viral infections?
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What is the consequence of inhibiting the re-uptake protein for neurotransmitters?
What is the consequence of inhibiting the re-uptake protein for neurotransmitters?
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What is the secretory region where neurotransmitters are released?
What is the secretory region where neurotransmitters are released?
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What is the role of kinesins in axonal transport?
What is the role of kinesins in axonal transport?
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What can pathogens like polio and rabies do by hijacking axonal transport?
What can pathogens like polio and rabies do by hijacking axonal transport?
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What is the consequence of calcium influx into the axon terminal?
What is the consequence of calcium influx into the axon terminal?
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Study Notes
Gastrointestinal Nervous System and its Modulation
- Certain chemical substances can activate chemo receptors
- Stimulation of chemo receptors can lead to activation of submucosal plexus neurons
- Stimulation can lead to release of certain chemicals that stimulate specific glands
- Glands can release secretions rich in bicarbonate
- Stimulation can also lead to dilation of blood vessels, increasing absorption
- Fatty chyme can stimulate submucosal plexus to release substances
- Specific cells called I cells can be stimulated to release cholecystokinin (CCK)
- CCK can cause gall bladder contractions and enhance pancreatic secretion
- Glucose can stimulate K cells to release glucose insulinotropic peptide (GIP)
- GIP can stimulate insulin production and inhibit gastric motility
- Intrinsic nervous system can autonomously respond to chemical and stretch sensations
- Sympathetic nervous system opposes motility, secretions, absorption, and blood flow in the GI tract
Enteric Nervous System and GI Motility
- The enteric nervous system is sometimes not included as part of the autonomic nervous system, but it is a gut brain with the same number of neurons as the entire spinal cord.
- The enteric nervous system consists of the myenteric plexus and the submucosal plexus, which regulate motility and secretions intrinsically.
- The myenteric plexus, also known as the Auerbach plexus, is located within the muscularis externa and consists of ascending and descending fibers.
- The submucosal plexus, also known as the Meissner plexus, is located within the submucosa and consists of areolar and dense connective tissue with glands.
- The alimentary canal has four basic layers: mucosa, submucosa, muscularis externa, and serosa/adventitia, and is histologically composed of epithelial tissue, lamina propria, and muscularis mucosa.
- The myenteric plexus stimulates circular muscle contraction and longitudinal muscle relaxation in response to stretch receptors, facilitating propulsion of food bolus.
- In response to stretch receptors, the myenteric plexus releases acetylcholine and substance P to stimulate circular muscle and vasoactive intestinal peptide and nitric oxide to inhibit longitudinal muscle.
- Chemo receptors are also present in the alimentary canal and respond to chemicals like fatty acids, glucose, and acidic residues, influencing enteric nervous system activity.
- The enteric nervous system can be stimulated by stretch receptors and chemo receptors to regulate GI motility intrinsically.
- Short reflex arcs and long reflex arcs involve the extrinsic effects of the sympathetic and parasympathetic nervous systems in altering intrinsic enteric nervous system activity.
- The enteric nervous system operates in response to different stimuli, such as food bolus distension, by regulating muscle contraction and relaxation to facilitate movement through the GI tract.
- The enteric nervous system can also be influenced by the release of specific chemicals in response to chemo receptors, affecting its activity in the regulation of GI motility.
The Function of the Axon and Axonal Transport
- The primary function of the axon is to conduct action potentials, involving a depolarizing wave of positive charge followed by a repolarizing wave of negative charge.
- Microtubules in the axon carry motor proteins, such as kinesin and dynein, involved in axonal transport.
- Kinesin is a positive-directed motor protein, responsible for anterograde axonal transport from the cell body to the axon terminal.
- Anterograde axonal transport involves the movement of organelles, neurotransmitters, vesicles, and enzymes from the cell body to the axon terminal.
- Dynein is a minus-directed motor protein, responsible for retrograde axonal transport from the axon terminal to the cell body.
- Retrograde axonal transport involves transporting organelles, such as mitochondria, and bringing up growth factors to the cell body.
- Action potentials involve the opening of voltage-gated sodium channels, leading to a flow of positive charges down the axon, and the opening of voltage-gated potassium channels, leading to a flow of negative charges to cause the cell to rest.
- The involvement of kinesin in axonal transport includes transporting vesicles containing neurotransmitters, membrane proteins, enzymes, and mitochondria.
- Dynein is involved in transporting vesicles and mitochondria that need to be degraded in retrograde axonal transport.
- The axon conducts action potentials through the flow of positive and negative charges, involving voltage-gated sodium and potassium channels.
- Kinesin is responsible for transporting various substances from the cell body to the axon terminal, while dynein is involved in transporting substances from the axon terminal to the cell body.
- Axonal transport and the function of the axon are clinically relevant, as they play a crucial role in the transportation of essential substances within the neuron.
Axonal Transport and Axon Terminal Function
- Axonal transport is the process of transporting materials along the axon using motor proteins, such as dyneins and kinesins.
- Nerve growth factors are transported by dyneins from the axon terminal to the cell body to stimulate gene expression and protein production for repair and growth.
- Pathogens like polio, rabies, herpes simplex, and varicella zoster viruses can hijack axonal transport to reach the cell body and use the nuclear machinery for replication.
- The axon terminal is the secretory region where neurotransmitters are released and re-uptake of neurotransmitters occurs.
- Depolarization of the axon terminal stimulates voltage-gated calcium channels, leading to calcium influx into the axon terminal.
- The vesicles in the axon terminal contain snare proteins (v-snares and t-snares) that are involved in neurotransmitter release.
- Calcium acts as a bridge between v-snares and t-snares, causing vesicle fusion with the axon terminal membrane and neurotransmitter release into the synapse.
- After exerting its effect, neurotransmitters need to be degraded or taken out of the synapse through re-uptake or degradation.
- Re-uptake involves the retrieval of neurotransmitters by the presynaptic neuron, while degradation occurs through enzymes in the synapse.
- The axon terminal plays a crucial role in neurotransmission and synaptic communication between neurons.
- Understanding axonal transport and axon terminal function is essential for comprehending the mechanisms of nerve signaling and the pathogenesis of certain viral infections.
- The proper functioning of axonal transport and the axon terminal is critical for maintaining neural communication and overall nervous system function.
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Description
Test your knowledge of the gastrointestinal nervous system and its modulation with this quiz. Explore how chemical substances, chemo receptors, and the enteric nervous system influence GI motility, secretions, and absorption. Learn about the enteric nervous system's intricate role in regulating gut function and its response to various stimuli.
