Podcast
Questions and Answers
In which part of the spinal cord are the preganglionic cell bodies of the sympathetic nervous system located?
In which part of the spinal cord are the preganglionic cell bodies of the sympathetic nervous system located?
What type of neurotransmitter is released by the postganglionic neurons of the sympathetic nervous system?
What type of neurotransmitter is released by the postganglionic neurons of the sympathetic nervous system?
Which of the following is NOT a function of the sympathetic nervous system?
Which of the following is NOT a function of the sympathetic nervous system?
What is the role of the adrenal medulla in the sympathetic nervous system?
What is the role of the adrenal medulla in the sympathetic nervous system?
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Which of the following best describes the function of the postganglionic neurons of the sympathetic nervous system?
Which of the following best describes the function of the postganglionic neurons of the sympathetic nervous system?
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Which of the following is NOT a characteristic of the sympathetic nervous system?
Which of the following is NOT a characteristic of the sympathetic nervous system?
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Which of the following organs is MOST likely to be directly affected by the release of norepinephrine from the sympathetic nervous system?
Which of the following organs is MOST likely to be directly affected by the release of norepinephrine from the sympathetic nervous system?
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How does the sympathetic nervous system differ from the parasympathetic nervous system in terms of its effect on the body?
How does the sympathetic nervous system differ from the parasympathetic nervous system in terms of its effect on the body?
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What is the primary difference between adrenaline and noradrenaline?
What is the primary difference between adrenaline and noradrenaline?
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What is the scientific term for an autoinjector syringe loaded with Epinephrine?
What is the scientific term for an autoinjector syringe loaded with Epinephrine?
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What is the main function of the parasympathetic nervous system?
What is the main function of the parasympathetic nervous system?
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Which of the following best describes the structure of preganglionic neurons in the parasympathetic nervous system?
Which of the following best describes the structure of preganglionic neurons in the parasympathetic nervous system?
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What is the effect of acetylcholine release onto muscarinic acetylcholine receptors in the parasympathetic nervous system?
What is the effect of acetylcholine release onto muscarinic acetylcholine receptors in the parasympathetic nervous system?
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Which cranial nerve carries parasympathetic signals to the heart?
Which cranial nerve carries parasympathetic signals to the heart?
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What is the effect of parasympathetic stimulation on the heart?
What is the effect of parasympathetic stimulation on the heart?
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Where are the preganglionic cell bodies for the sympathetic innervation of the heart located?
Where are the preganglionic cell bodies for the sympathetic innervation of the heart located?
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What neurotransmitter is released by sympathetic postganglionic neurons to speed up the heart?
What neurotransmitter is released by sympathetic postganglionic neurons to speed up the heart?
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What is the effect of sympathetic stimulation on the pupil of the eye?
What is the effect of sympathetic stimulation on the pupil of the eye?
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What is the scientific term for pupil constriction?
What is the scientific term for pupil constriction?
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What is the name of the drug that was traditionally used to dilate pupils, historically believed to make women more attractive?
What is the name of the drug that was traditionally used to dilate pupils, historically believed to make women more attractive?
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Which of the following is NOT a reason for pupil dilation?
Which of the following is NOT a reason for pupil dilation?
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What is the primary neurotransmitter released by the parasympathetic postganglionic neurons?
What is the primary neurotransmitter released by the parasympathetic postganglionic neurons?
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What is the name given to the clusters of postganglionic neurons found within the walls of target organs in the parasympathetic nervous system?
What is the name given to the clusters of postganglionic neurons found within the walls of target organs in the parasympathetic nervous system?
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What is the origin of the name "belladonna"?
What is the origin of the name "belladonna"?
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Study Notes
Motor Systems
- Motor systems utilize effectors (muscles or glands) to respond to nervous system output.
- The somatic motor system controls skeletal muscle contraction.
- The autonomic (or visceral) motor system manages smooth muscle, cardiac muscle, and glandular secretions.
Autonomic Nervous System
- Composed of two neuron pathways: preganglionic and postganglionic neurons.
- Preganglionic neuron: cell body in CNS, axon synapses in an autonomic ganglion.
- Postganglionic neuron: cell body in an autonomic ganglion, axon innervates the effector organ (e.g., muscle, gland).
Sympathetic Nervous System ("Fight-Flight-Freeze")
- Preganglionic cell bodies located in the spinal cord (T1-L2).
- Short preganglionic axons synapse in nearby sympathetic chain ganglia.
- Postganglionic axons release norepinephrine (noradrenaline) onto target organs.
- Activates the entire body simultaneously.
Sympathetic Response Examples
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Pupil dilation
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Dry mouth
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Increased heart rate
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Lung airway dilation
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Sweating
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Digestive system shutdown
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Blood redirection to skeletal muscles
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Stimulates adrenal medulla to release epinephrine (adrenaline), traveling in bloodstream to activate the same receptors as norepinephrine.
Adrenaline/Epinephrine and Noradrenaline/Norepinephrine
- Adrenaline and epinephrine are chemically identical.
- Noradrenaline is a neurotransmitter, and adrenaline is a hormone, released from the adrenal medulla.
- "Nor-" prefix refers to the addition of a methyl group (–CH3) to noradrenaline. Both bind to the same class of receptors (adrenergic).
Parasympathetic Nervous System ("Rest-and-Digest")
- Different anatomy than sympathetic.
- Long preganglionic axons extend directly to the target organ.
- Short postganglionic axons in intramural ganglia (within the organ wall).
- Controls organs individually, not systemically.
- Preganglionic neurons for head, thorax, and abdomen located in brainstem.
- Preganglionic neurons for abdomen, retroperitoneum, and genitals located in the sacral spinal cord. Axons travel in the vagus nerve (cranial nerve X) or pelvic splanchnic nerves.
- Postganglionic neurons release acetylcholine onto muscarinic acetylcholine receptors.
Heart Innervation
- Parasympathetic: Slows heart rate; uses acetylcholine on pacemaker cells (dorsal motor nucleus of the vagus, vagus nerve).
- Sympathetic: Speeds heart rate; uses norepinephrine on pacemaker cells (lateral horn of spinal cord, T1-T5, cardiac accelerator nerve).
Iris Innervation
- Sympathetic: Dilates pupils (mydriasis).
- Parasympathetic: Constricts pupils (miosis).
- Atropine: Blocks acetylcholine receptors, causing pupil dilation and increased heart rate.
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Description
This quiz covers the fundamentals of motor systems, including the somatic and autonomic motor systems. It delves into the sympathetic nervous system's structure and responses, providing a comprehensive understanding of how the nervous system influences bodily functions. Test your knowledge on these critical concepts in physiology.
