GI Nervous System Quiz

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Questions and Answers

What can activate chemo receptors in the gastrointestinal nervous system?

Temperature changes

Mechanical pressure

Microbial activity

Certain chemical substances (correct)

What can stimulation of chemo receptors lead to in the gastrointestinal nervous system?

Activation of submucosal plexus neurons (correct)

Activation of skeletal muscle cells

Activation of smooth muscle cells

Activation of myenteric plexus neurons

What type of secretions can specific glands release in the gastrointestinal nervous system?

Secretions rich in bicarbonate (correct)

Secretions rich in amino acids

Secretions rich in lipids

Secretions rich in glucose

What can fatty chyme stimulate in the gastrointestinal nervous system?

Submucosal plexus to release substances Signup and view all the answers

What can be stimulated to release cholecystokinin (CCK) in the gastrointestinal nervous system?

Specific cells called I cells Signup and view all the answers

What can glucose stimulate in the gastrointestinal nervous system?

K cells to release glucose insulinotropic peptide (GIP) Signup and view all the answers

What can autonomously respond to chemical and stretch sensations in the gastrointestinal nervous system?

Intrinsic nervous system Signup and view all the answers

What does the sympathetic nervous system oppose in the gastrointestinal tract?

Motility, secretions, absorption, and blood flow Signup and view all the answers

Where is the myenteric plexus located?

Within the muscularis externa Signup and view all the answers

What are the components of the enteric nervous system?

Myenteric plexus and submucosal plexus Signup and view all the answers

What is the function of the myenteric plexus?

Stimulates circular muscle contraction and longitudinal muscle relaxation Signup and view all the answers

What can influence the activity of the enteric nervous system?

Release of specific chemicals in response to chemo receptors Signup and view all the answers

What are the components of the alimentary canal?

Mucosa, submucosa, muscularis externa, and serosa/adventitia Signup and view all the answers

What is the role of the submucosal plexus?

Regulate secretions intrinsically Signup and view all the answers

What do chemo receptors in the alimentary canal respond to?

Chemicals like fatty acids, glucose, and acidic residues Signup and view all the answers

What can the enteric nervous system be stimulated by to regulate GI motility?

Stretch receptors and chemo receptors Signup and view all the answers

What is the role of 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 Signup and view all the answers

What does the myenteric plexus release in response to stretch receptors?

Acetylcholine and substance P Signup and view all the answers

What is the histological composition of the alimentary canal?

Epithelial tissue, lamina propria, and muscularis mucosa Signup and view all the answers

What is the primary function of the reuptake protein mentioned in the text?

To move neurotransmitter back into the axon terminal for recycling Signup and view all the answers

What is the specific name of the reuptake protein for serotonin mentioned in the text?

Serotonin reuptake protein Signup and view all the answers

What is the consequence of inhibiting the reuptake protein for serotonin?

Increased levels of serotonin in the synaptic cleft Signup and view all the answers

What is the purpose of incorporating neurotransmitters back into vesicles in the axon terminal?

To recycle and reuse the neurotransmitters Signup and view all the answers

Where does protein synthesis take place in neurons?

Rough endoplasmic reticulum Signup and view all the answers

What is responsible for releasing neurotransmitters to communicate with other neurons or target cells?

Axon terminals Signup and view all the answers

Which part of the neuron is involved in the transmission of electrical signals generated by the cell body to the axon terminal?

Axon Signup and view all the answers

What determines whether an action potential will be initiated and propagated along the axon?

Integration of EPSPs and IPSPs at the axon hillock Signup and view all the answers

Where are synthesized proteins, such as neurotransmitters, packaged into vesicles?

Golgi apparatus Signup and view all the answers

What is the role of the dendrites in neuronal function?

Involved in graded potentials via ligand-gated ion channels Signup and view all the answers

What is the function of the axon in a neuron?

Transmission of electrical signals Signup and view all the answers

Where does the process of DNA transcription occur in neurons?

Nucleus Signup and view all the answers

What is the main function of the axon terminal in a neuron?

Release neurotransmitters Signup and view all the answers

Where are synaptic vesicles containing neurotransmitters released from?

Axon terminal Signup and view all the answers

What is the role of the cell bodies in a neuron?

Involved in graded potentials and protein synthesis Signup and view all the answers

What is the function of dendrites in a neuron?

Receptive zone of a neuron Signup and view all the answers

What determines whether an action potential will be initiated and propagated along the axon in a neuron?

Integration of EPSPs and IPSPs at the axon hillock Signup and view all the answers

What is the role of EPSPs in a neuron?

Depolarize the cell and stimulate the neuron to fire Signup and view all the answers

What is the function of the axon terminal in a neuron?

Site of neurotransmitter release Signup and view all the answers

What is the role of IPSPs in a neuron?

Hyperpolarize the cell and inhibit the generation of action potentials Signup and view all the answers

What is the location where the cell body narrows and goes into the axon called?

Axon hillock Signup and view all the answers

What are graded potentials involved in?

Generation and propagation of action potentials Signup and view all the answers

What is the elongated portion between the cell body and axon terminal called?

Axon Signup and view all the answers

What are EPSPs and IPSPs collectively known as?

Graded potentials Signup and view all the answers

What do dendrites have that are involved in the formation of EPSPs and IPSPs?

Ligand-gated ion channels Signup and view all the answers

What is the circular structure with various components inside called in a neuron?

Cell body (soma) Signup and view all the answers

What do IPSPs do to the cell's charge?

Hyperpolarize the cell, making it more negative Signup and view all the answers

What is the bulbous structure at the end of the neuron called?

Axon terminal Signup and view all the answers

What is the primary function of the axon?

Conducting action potentials Signup and view all the answers

Which motor protein is responsible for anterograde axonal transport?

Kinesin Signup and view all the answers

What does retrograde axonal transport involve?

Transporting organelles to the cell body Signup and view all the answers

What is the role of dynein in axonal transport?

Responsible for retrograde axonal transport Signup and view all the answers

What is the function of kinesin in axonal transport?

Transporting vesicles containing neurotransmitters Signup and view all the answers

What do action potentials involve?

Opening of voltage-gated sodium channels Signup and view all the answers

What is the involvement of dynein in retrograde axonal transport?

Transporting vesicles and mitochondria for degradation Signup and view all the answers

What substances does kinesin transport from the cell body to the axon terminal?

Neurotransmitters, membrane proteins, enzymes, and mitochondria Signup and view all the answers

What is the clinical relevance of axonal transport and the function of the axon?

They play a crucial role in the transportation of essential substances within the neuron Signup and view all the answers

How does the axon conduct action potentials?

Through the flow of positive and negative charges Signup and view all the answers

What substances does dynein transport from the axon terminal to the cell body?

Vesicles and mitochondria for degradation Signup and view all the answers

What are microtubules in the axon responsible for carrying?

Motor proteins involved in axonal transport Signup and view all the answers

What is the role of dyneins in axonal transport?

Transport nerve growth factors from the axon terminal to the cell body Signup and view all the answers

What can pathogens like polio and rabies viruses do in relation to axonal transport?

Hijack axonal transport to reach the cell body for replication Signup and view all the answers

What stimulates voltage-gated calcium channels in the axon terminal?

Depolarization of the axon terminal Signup and view all the answers

What is the function of snare proteins in the axon terminal?

Involved in neurotransmitter release Signup and view all the answers

What occurs through re-uptake and degradation in the synapse?

Retrieval of neurotransmitters and breakdown by enzymes Signup and view all the answers

What is the crucial role of the axon terminal?

In neurotransmission and synaptic communication between neurons Signup and view all the answers

Why is understanding axonal transport and axon terminal function essential?

For comprehending the mechanisms of nerve signaling and the pathogenesis of certain viral infections Signup and view all the answers

What is the consequence of inhibiting the reuptake protein for serotonin?

Prolonged presence of serotonin in the synapse Signup and view all the answers

Where does the process of DNA transcription occur in neurons?

Cell body Signup and view all the answers

What is the primary function of the axon?

Conducting action potentials Signup and view all the answers

What is the location where the cell body narrows and goes into the axon called?

Axon hillock Signup and view all the answers

What is the elongated portion between the cell body and axon terminal called?

Axon Signup and view all the answers

Which motor proteins are involved in axonal transport?

Dyneins and kinesins Signup and view all the answers

What is the role of dyneins in axonal transport?

Transporting pathogens to the cell body Signup and view all the answers

What stimulates the release of neurotransmitters into the synapse from the axon terminal?

Depolarization of the axon terminal Signup and view all the answers

What is the function of v-snares and t-snares in the axon terminal?

Involved in neurotransmitter release Signup and view all the answers

What occurs through re-uptake or degradation of neurotransmitters in the synapse?

Neurotransmitter clearance Signup and view all the answers

What is the primary role of the axon terminal in a neuron?

Neurotransmission and synaptic communication Signup and view all the answers

What is essential for comprehending the mechanisms of nerve signaling and the pathogenesis of certain viral infections?

Understanding axonal transport and axon terminal function Signup and view all the answers

What is the consequence of inhibiting the re-uptake protein for neurotransmitters?

Increased neurotransmitter release Signup and view all the answers

What is the secretory region where neurotransmitters are released?

Axon terminal Signup and view all the answers

What is the role of kinesins in axonal transport?

Transporting nerve growth factors from the axon terminal to the cell body Signup and view all the answers

What can pathogens like polio and rabies do by hijacking axonal transport?

Reach the cell body for replication Signup and view all the answers

What is the consequence of calcium influx into the axon terminal?

Facilitation of vesicle fusion and neurotransmitter release Signup and view all the answers

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.