Block 9 Rx Automomics MCQ's
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Untreated or poorly controlled type 2 diabetes mellitus leads to autonomic insufficiency and peripheral neuropathy, In such an individual, what would be an expected problem associated with assuming an upright posture?
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Inability to contract skeletal muscles of the legs.
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Postural hypotension
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Extreme tachycardia
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Postural hypertension
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This Block 9 Rx Automomics MCQs quiz assesses understanding of autonomic nervous system disorders, reflex pathways, and pharmacological impacts on heart rate. It is designed for medical students preparing for exams, enhancing their knowledge in physiology and pathophysiology.
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- 2.
The following concept map describes some of the neural pathways by which the autonomic nervous system acts as an efferent pathway in the baroreceptor reflex. For each step of this reflex pathway there is a box which describes the relationship between input and output. For example, the second box shows that firing rate of NTS neurons (output) receiving baroreceptor afferent input increases with increases in mean arterial pressure, MAP (input). In the concept map below which block incorrectly describes an input/output relationship?
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1
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2
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3
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4
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5
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6
Correct Answer
A. 4 -
- 3.
If one considers the anatomical differences between the sympathetic and parasympathetic nervous systems, what would be the most likely explanation for the finding that there is a shorter delay for the parasympathetic nervous system to decrease heart rate compared to the delay associated with ability of the sympathetic nervous system to increase heart rate?
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Sympathetic preganglionic neurons are found in the intermediolateral cell column
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Parasympathetic motoneurans are found in the medulla oblongata
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Parasympathetic preganglionic fibers are myelinated and the postganglionic axons are short.
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Sympathetic preganglionic axons are myelinated and postganglionic axons are long
Correct Answer
A. Parasympathetic preganglionic fibers are myelinated and the postganglionic axons are short.Explanation
The most likely explanation for the finding that there is a shorter delay for the parasympathetic nervous system to decrease heart rate compared to the delay associated with the ability of the sympathetic nervous system to increase heart rate is that parasympathetic preganglionic fibers are myelinated and the postganglionic axons are short. Myelination allows for faster transmission of nerve impulses, while shorter axons result in a shorter distance for the impulse to travel. Therefore, the parasympathetic nervous system can quickly transmit signals to decrease heart rate.Rate this question:
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- 4.
A 19-year-old male is stabbed in the upper back, severing the spinal cord between C6- C7. In addition to other symptoms such as paralysis, which of the following autonomic symptoms would you expect to find following the injury?
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Sweaty palms
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Tachycardia (increased heart rate)
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Constricted pupils (miosis)
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Dilated pupils (mydriasis)
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Excessive watery salivation
Correct Answer
A. Constricted pupils (miosis)Explanation
When the spinal cord is severed between C6-C7, it affects the sympathetic outflow from the spinal cord. This results in interruption of sympathetic innervation to the head and face. The sympathetic fibers that control pupillary dilation (mydriasis) are affected, leading to a loss of sympathetic tone and resulting in constricted pupils (miosis). Therefore, constricted pupils would be expected as an autonomic symptom following this injury.Rate this question:
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- 5.
The pre-ganglionic neurons of the parasympathetic nervous system originate within all of the following central nervous system regions EXCEPT:
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Cranial Nerve III
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Cranial Nerve IX
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Cranial Nerve X
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S1
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S2
Correct Answer
A. S1Explanation
The pre-ganglionic neurons of the parasympathetic nervous system originate within the cranial nerves III, IX, and X, as well as the sacral spinal cord segments S2-S4. However, they do not originate within the sacral spinal cord segment S1.Rate this question:
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- 6.
Your patient is suffering from bradycardia. Which of the following pharmacological approaches would most effectively initially counteract this bradycardia?
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Stimulate beta 1 receptors
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Inhibit beta 1 receptors
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Stimulate beta 2 receptors
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Stimulate alpha 1 receptors
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Inhibit alpha 1 receptors
Correct Answer
A. Stimulate beta 1 receptorsExplanation
Stimulating beta 1 receptors would most effectively initially counteract bradycardia. Beta 1 receptors are found in the heart and their stimulation increases heart rate and cardiac output. By stimulating beta 1 receptors, the heart rate can be increased, which would help counteract the slow heart rate associated with bradycardia.Rate this question:
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- 7.
A 44 year old female patient is referred to your clinic because of increased sweating on the face and neck, despite cool ambient temperatures. The neurotransmitter responsible for eliciting sweating, if applied to the cardiac muscle, would do which of the following?
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Increase heart rate
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Reduce heart rate
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Have no effect on heart rate
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Bind to beta 1 receptors
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Bind to M3 receptors
Correct Answer
A. Reduce heart rateExplanation
The neurotransmitter responsible for eliciting sweating is likely acetylcholine, which acts on M3 receptors to stimulate sweat production. If acetylcholine is applied to the cardiac muscle, it would bind to M3 receptors and have no effect on heart rate. Therefore, the correct answer is "have no effect on heart rate."Rate this question:
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- 8.
A 46 year old male patient, who complains of being overworked and subject to high levels of stress at the office, presents with tachycardia, severe hypertension, and mild chest pain. In order to reduce the hypertension and tachycardia you would advise a pharmacological approach involving
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A non-selective beta agonist
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A B3 receptor antagonist
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A B1 receptor antagonist
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A M2 receptor antagonist
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A B2 receptor antagonist
Correct Answer
A. A B1 receptor antagonistExplanation
In this scenario, the patient is experiencing symptoms such as tachycardia, severe hypertension, and mild chest pain. These symptoms are indicative of increased sympathetic activity, which is mediated by the beta-1 adrenergic receptors. By blocking these receptors with a beta-1 receptor antagonist, the sympathetic activity can be reduced, leading to a decrease in heart rate and blood pressure. This pharmacological approach would be effective in managing the patient's hypertension and tachycardia.Rate this question:
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- 9.
A 63 year old chronic smoker is informed that he has a tumor in the apex of his right lung. While not pleased, he does understand the correlation between smoking and increased risk for lung cancer. He is confused, however, by some recent facial symptoms including drooping of his right eyelid. His physician notices slight miosis of the right pupil as well. The miosis in this patient is due to
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Enhanced release of norepinephrine by post-ganglionic sympathetic fibers
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Reduced release of norepinephrine from sympathetic post-ganglionic fibers
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Acetylcholine released from post-ganglionic sympathetic fibers
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Activation of alpha 1 receptors
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Loss of parasympathetic innervation of the sphincter muscle of the eye
Correct Answer
A. Reduced release of norepinephrine from sympathetic post-ganglionic fibersExplanation
The miosis in this patient is due to reduced release of norepinephrine from sympathetic post-ganglionic fibers. Miosis refers to constriction of the pupil, which is controlled by the iris sphincter muscle. The sympathetic nervous system normally causes dilation of the pupil by releasing norepinephrine from post-ganglionic fibers. In this patient, the tumor in the apex of the right lung may be affecting the sympathetic innervation to the eye, leading to reduced release of norepinephrine and subsequent miosis.Rate this question:
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- 10.
A 56 year old woman is treated by her neurologist because of weakness in her hands, mild ataxia and bradykinesia (slowness of movement). In addition to these motor symptoms she exhibits pronounced drops in blood pressure, especially after sitting for long periods. No one in her family has a history of Parkinson's disease. You suspect?
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Pheochrornocytosis
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Shy drager syndrome
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Raynaud syndrome
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Homer's syndrome
Correct Answer
A. Shy drager syndromeExplanation
The correct answer is Shy drager syndrome. Shy drager syndrome, also known as multiple system atrophy (MSA), is a rare neurological disorder that affects multiple systems in the body. It is characterized by a combination of motor symptoms such as weakness, ataxia, and bradykinesia, as well as autonomic symptoms including drops in blood pressure. Unlike Parkinson's disease, which primarily affects the motor system, Shy drager syndrome involves dysfunction of both the motor and autonomic systems. The absence of a family history of Parkinson's disease suggests a different underlying cause for the patient's symptoms.Rate this question:
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- 11.
A 45-year-old man was treated topically with eye drops during a routine ophthalmoscopic examination. Now he complains that he is blinded by bright light and is unable to focus on near objects. These symptoms most likely result from a blockade of M3 receptors located on which of the following pairs of eye structures?
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Radial muscle of iris and Schlemm canal
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Sphincter of iris and ciliary muscle
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Trabecular meshwork and radial muscle of ins
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Ciliary epithelium and retina
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Retina and lens
Correct Answer
A. Ciliary epithelium and retinaExplanation
Activation of M3 receptors located on the sphincter of iris causes contraction of the muscle so
causing miosis. On the contrary blockade of these receptors causes mydriasis and impairment
of the pupillary constriction in bright light (the light pupillary reflex) so leading to photophobia.
Activation of M3 receptors located on the ciliary muscle causes contraction of the muscle,
which in turn increases lens curvature. The process, called accommodation, allows the eye to
focus on near objects. On the contrary blockade of these receptors relaxes the ciliary muscle
(cycloplegia) and impairs the accommodation process.
A, B, C, E) (see explanation above)Rate this question:
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.JPG "The following concept map describes some of the neural pathways by which the autonomic nervous system acts as an efferent pathway in the baroreceptor reflex. For each step of this reflex pathway there is a box which describes the relationship between input and output. For example, the second box shows that firing rate of NTS neurons (output) receiving baroreceptor afferent input increases with increases in mean arterial pressure, MAP (input).
In the concept map below which block incorrectly describes an input/output relationship?")
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Aug 08, 2024Quiz Edited by
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May 18, 2012Quiz Created by
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