Peripheral Nervous System
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Anatomy › Peripheral Nervous System
Which of the following is a feature of the sympathetic nervous system?
Some sympathetic fibers pass through the paravertebral ganglia of the sympathetic trunk; other sympathetic fibers synapse there
Some sympathetic fibers leave the central nervous system (CNS) by specific cranial nerves
Sympathetic fibers exit the spinal cord by dorsal roots of spinal nerves
Sympathetic stimulation causes dilation of blood vessels in the skin of the back and limbs
Explanation
The sympathetic nervous system is one of two divisions of the autonomic nervous system; it is responsible for the "fight or flight" response and is involved in homeostasis. Some sympathetic fibers pass through the paravertebral ganglia of the sympathetic trunk, while other sympathetic fibers synapse there.
Parasympathetic nerves are associated with cranial nerves, and the dilation of blood vessels in skin of the back and limbs (the sympathetic system constricts these vessels). Preganglionic neurons originate in the thoracolumbar region of the spinal cord (T2 to L1) then travel to a paravertebral ganglion or prevertebral ganglion, where they synapse with a postganglionic neruon. The paravertebral ganglion are found throughout the length of the spinal cord, including the cervical, thoracic, lumbar, and sacral areas.
Which cranial nerves are part of the visceral efferent parasympathetic in the peripheral nervous system (PNS)?
III, VII, IX, and X
III, VII, VIII, and IX
VII, IX, and X
VII and IX
III, VII, IX, and XI
Explanation
The cranial nerves that are part of the visceral efferent parasympathetic in the PNS are III, VII, IX, and X. Cranial nerve III (oculomotor) travels to the ciliary ganglion and supplies the pupil of the eye for constriction. Cranial nerve VII (facial) travels to the pterygomandibular and submandibular ganglion and supplies the lacrimal and salivary glands. Cranial nerve IX (glossopharyngeal) travels to the otic ganglion and supplies the Parotid gland. Lastly, cranial nerve X (vagus) travels to the Prevertebral plexus and thoracic plexus in order to supply the gut, heart, and enteric system.
Atropine is a molecule that is an antagonist to muscarinic cholinergic receptors. Based on your knowledge of autonomic nervous system physiology, how would you expect the pupils to respond to topical administration of atropine?
You will observe mydriasis (pupil dilation)
You will observe miosis (pupil constriction)
There will be no change in pupil size because the pupils do not have muscarinic receptors
The iris sphincter muscles would experience a relaxed paralysis
The iris sphincter muscles would experience a contracted paralysis
Explanation
The pupillary sphincter muscles contain muscarinic cholinergic receptors that help the eyes to respond to parasympathetic tone. When this parasympathetic signal is blocked (antagonized) via atropine, you will observe a "sympathetic response" at the level of the pupil. In this scenario, you would observe the sympathetic response of pupil dilation. Hint: "aTROP'ine" and "seeing a TROPical setting" both cause your pupils to dilate nice and wide!
How is the parasympathetic branch of the autonomic nervous system organized?
Long preganglionic fiber, short postganglionic fiber
Short preganglionic fiber, long postganglionic fiber
Short preganglionic fiber, short postganglionic fiber
Long preganglionic fiber, long postganglionic fiber
Explanation
Cell bodies of preganglionic neurons are located in the central nervous system (CNS); they synapse onto autonomic ganglia. Parasympathetic ganglia are located in or near the effector organs giving them long preganglionic fibers and short postganglionic fiber. Sympathetic ganglia are located in the paravertebral chain, thus they have short preganglionic fibers and long postganglionic fibers.
Atropine is a molecule that is an antagonist to muscarinic cholinergic receptors. Based on your knowledge of autonomic nervous system physiology, how would you expect the pupils to respond to topical administration of atropine?
You will observe mydriasis (pupil dilation)
You will observe miosis (pupil constriction)
There will be no change in pupil size because the pupils do not have muscarinic receptors
The iris sphincter muscles would experience a relaxed paralysis
The iris sphincter muscles would experience a contracted paralysis
Explanation
The pupillary sphincter muscles contain muscarinic cholinergic receptors that help the eyes to respond to parasympathetic tone. When this parasympathetic signal is blocked (antagonized) via atropine, you will observe a "sympathetic response" at the level of the pupil. In this scenario, you would observe the sympathetic response of pupil dilation. Hint: "aTROP'ine" and "seeing a TROPical setting" both cause your pupils to dilate nice and wide!
Which of the following is not considered to be a mechanoreceptor?
Free nerve ending
Pacinian corpuscle
Ruffini ending
Meissner's corpuscle
Merkel receptor
Explanation
Mechanoreceptors are associated with the perception of touch/proprioception. With this being said, free nerve endings give nociceptive sensory information to perceive pain and would not be considered mechanoreceptors, while all other options are.
Which of the following is a feature of the sympathetic nervous system?
Some sympathetic fibers pass through the paravertebral ganglia of the sympathetic trunk; other sympathetic fibers synapse there
Some sympathetic fibers leave the central nervous system (CNS) by specific cranial nerves
Sympathetic fibers exit the spinal cord by dorsal roots of spinal nerves
Sympathetic stimulation causes dilation of blood vessels in the skin of the back and limbs
Explanation
The sympathetic nervous system is one of two divisions of the autonomic nervous system; it is responsible for the "fight or flight" response and is involved in homeostasis. Some sympathetic fibers pass through the paravertebral ganglia of the sympathetic trunk, while other sympathetic fibers synapse there.
Parasympathetic nerves are associated with cranial nerves, and the dilation of blood vessels in skin of the back and limbs (the sympathetic system constricts these vessels). Preganglionic neurons originate in the thoracolumbar region of the spinal cord (T2 to L1) then travel to a paravertebral ganglion or prevertebral ganglion, where they synapse with a postganglionic neruon. The paravertebral ganglion are found throughout the length of the spinal cord, including the cervical, thoracic, lumbar, and sacral areas.
Which cranial nerves are part of the visceral efferent parasympathetic in the peripheral nervous system (PNS)?
III, VII, IX, and X
III, VII, VIII, and IX
VII, IX, and X
VII and IX
III, VII, IX, and XI
Explanation
The cranial nerves that are part of the visceral efferent parasympathetic in the PNS are III, VII, IX, and X. Cranial nerve III (oculomotor) travels to the ciliary ganglion and supplies the pupil of the eye for constriction. Cranial nerve VII (facial) travels to the pterygomandibular and submandibular ganglion and supplies the lacrimal and salivary glands. Cranial nerve IX (glossopharyngeal) travels to the otic ganglion and supplies the Parotid gland. Lastly, cranial nerve X (vagus) travels to the Prevertebral plexus and thoracic plexus in order to supply the gut, heart, and enteric system.
Atropine is a molecule that is an antagonist to muscarinic cholinergic receptors. Based on your knowledge of autonomic nervous system physiology, how would you expect the pupils to respond to topical administration of atropine?
You will observe mydriasis (pupil dilation)
You will observe miosis (pupil constriction)
There will be no change in pupil size because the pupils do not have muscarinic receptors
The iris sphincter muscles would experience a relaxed paralysis
The iris sphincter muscles would experience a contracted paralysis
Explanation
The pupillary sphincter muscles contain muscarinic cholinergic receptors that help the eyes to respond to parasympathetic tone. When this parasympathetic signal is blocked (antagonized) via atropine, you will observe a "sympathetic response" at the level of the pupil. In this scenario, you would observe the sympathetic response of pupil dilation. Hint: "aTROP'ine" and "seeing a TROPical setting" both cause your pupils to dilate nice and wide!
How is the parasympathetic branch of the autonomic nervous system organized?
Long preganglionic fiber, short postganglionic fiber
Short preganglionic fiber, long postganglionic fiber
Short preganglionic fiber, short postganglionic fiber
Long preganglionic fiber, long postganglionic fiber
Explanation
Cell bodies of preganglionic neurons are located in the central nervous system (CNS); they synapse onto autonomic ganglia. Parasympathetic ganglia are located in or near the effector organs giving them long preganglionic fibers and short postganglionic fiber. Sympathetic ganglia are located in the paravertebral chain, thus they have short preganglionic fibers and long postganglionic fibers.