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Questions and Answers
What is the role of calcium ions (Ca2+) in the release of acetylcholine (ACh)?
What is the role of calcium ions (Ca2+) in the release of acetylcholine (ACh)?
Where are nicotinic receptors found in the autonomic nervous system?
Where are nicotinic receptors found in the autonomic nervous system?
What substance produces effects similar to the stimulation of central cholinergic fibers?
What substance produces effects similar to the stimulation of central cholinergic fibers?
What enzyme hydrolyzes acetylcholine into acetate and choline?
What enzyme hydrolyzes acetylcholine into acetate and choline?
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What is the primary function of nicotinic receptors?
What is the primary function of nicotinic receptors?
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What effect does hexamethonium have on nicotinic receptors?
What effect does hexamethonium have on nicotinic receptors?
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What is the result of ACh binding to its receptors in the postganglionic neuron?
What is the result of ACh binding to its receptors in the postganglionic neuron?
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Which of the following is NOT a characteristic of nicotinic receptors?
Which of the following is NOT a characteristic of nicotinic receptors?
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What is the function of the collateral ganglia in the autonomic nervous system?
What is the function of the collateral ganglia in the autonomic nervous system?
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What characteristic of sympathetic responses is primarily due to divergence of preganglionic fibers?
What characteristic of sympathetic responses is primarily due to divergence of preganglionic fibers?
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How many postganglionic neurons does a single sympathetic preganglionic fiber typically activate?
How many postganglionic neurons does a single sympathetic preganglionic fiber typically activate?
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Where are terminal ganglia primarily located?
Where are terminal ganglia primarily located?
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What is the primary neurotransmitter released at all preganglionic endings in the autonomic nervous system?
What is the primary neurotransmitter released at all preganglionic endings in the autonomic nervous system?
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In contrast to sympathetic ganglia, the activation pattern of parasympathetic ganglia results in which kind of response?
In contrast to sympathetic ganglia, the activation pattern of parasympathetic ganglia results in which kind of response?
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What role do autonomic ganglia play in the nervous system?
What role do autonomic ganglia play in the nervous system?
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What is the primary method of synaptic transmission between preganglionic and postganglionic neurons in autonomic ganglia?
What is the primary method of synaptic transmission between preganglionic and postganglionic neurons in autonomic ganglia?
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What is the primary function of the autonomic ganglia?
What is the primary function of the autonomic ganglia?
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Where do sympathetic preganglionic neurons originate?
Where do sympathetic preganglionic neurons originate?
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How do postganglionic neurons in autonomic ganglia function?
How do postganglionic neurons in autonomic ganglia function?
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What differentiates the location of parasympathetic ganglia from sympathetic ganglia?
What differentiates the location of parasympathetic ganglia from sympathetic ganglia?
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What neurotransmitters are primarily secreted by the chromaffin cells in the adrenal medulla?
What neurotransmitters are primarily secreted by the chromaffin cells in the adrenal medulla?
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Which statement accurately describes the structure of paravertebral ganglia?
Which statement accurately describes the structure of paravertebral ganglia?
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How are autonomic ganglia classified based on their sites?
How are autonomic ganglia classified based on their sites?
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What is the relationship between preganglionic and postganglionic neurons in the autonomic nervous system?
What is the relationship between preganglionic and postganglionic neurons in the autonomic nervous system?
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Study Notes
Autonomic Ganglia
- Autonomic ganglia are clusters of neuron cell bodies outside the central nervous system (CNS).
- Two main types: sympathetic and parasympathetic ganglia.
- Sympathetic ganglia are part of the sympathetic division of the autonomic nervous system (ANS).
- Parasympathetic ganglia are part of the parasympathetic division of the ANS.
Organization of the ANS
- Preganglionic neurons have cell bodies in the CNS and synapse in autonomic ganglia.
- Sympathetic preganglionic neurons originate in the spinal cord segments T1-L3 (thoraco-lumbar region).
- Parasympathetic preganglionic neurons originate in cranial nerve nuclei and spinal cord segments S2-S4 (cranio-sacral region).
- Synapses occur in autonomic ganglia.
- Parasympathetic ganglia are located near or within the effector organs.
- Sympathetic ganglia are located in the paravertebral chain.
- Postganglionic neurons emerge from autonomic ganglia and connect to effector organs (e.g. heart, blood vessels, and sweat glands).
Types of Autonomic Ganglia
- Paravertebral (lateral) ganglia form chains alongside the spinal column.
- Collateral ganglia located between the sympathetic chain and target organs, relaying signals to abdominal viscera and pelvis.
- Terminal ganglia are positioned near or on the target organs. They receive signals from parasympathetic preganglionic neurons.
Functions of Autonomic Ganglia
- Act as relay centers for preganglionic axons, with a preganglionic axon synapsing with multiple postganglionic neurons.
- This divergences spreads nerve impulses throughout the body for sympathetic responses, and localizes parasympathetic responses to a specific effector organ.
Synaptic Transmission
- Synaptic transmission between neurons in autonomic ganglia uses acetylcholine (ACh) to relay signals, and is a chemical process. Cholinergic neurons secrete ACh.
- ACh triggers depolarization in the postganglionic neuron. Calcium influx triggers vesicle fusion and release of ACh into the synaptic cleft.
- ACh binds to nicotinic receptors, and triggers postsynaptic membrane depolarization to create an action potential.
- Enzymes (e.g. Acetylcholinesterase) rapidly break down ACh.
Adrenal Medulla
- A specialized sympathetic ganglion where preganglionic fibers directly synapse on chromaffin cells.
- Chromaffin cells secrete epinephrine (adrenaline) and norepinephrine (noradrenaline) into the bloodstream.
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Description
Explore the structure and organization of autonomic ganglia, including their roles in the sympathetic and parasympathetic divisions of the autonomic nervous system. This quiz covers the origins of preganglionic neurons, the location of ganglia, and the connections to effector organs. Test your knowledge on this essential aspect of human physiology!
