CHAPTER 22 Flashcards
- All of the following statements concerning Lambert-Eaton myasthenic Syndrome are correct EXCEPT
(A) it is associated with carcinoma of the lung
(B) it is an autoimmune syndrome that occurs in the presence of antibodies to the nicotinic acetylcholine (ACh) receptors
(C) it does not affect the bulbar muscles
(D) it commonly does not affect the limb muscles at presentation
(E) muscle strength improves with use
l-B. Lambert-Eaton myasthenic syndrome is caused by a presynaptic defect of acetylcholine (ACh) release. The importance of this relatively uncommon syndrome is its relation to neoplasms; 50% of cases are associated with malignancy. Note that bulbar muscles, which are innervated by motor cranial nerves, are not affected. Muscle strength improves with use. Autonomic dysfunction is common (e.g., dry mouth, incontinence).
- All of the following statements concerning myasthenia gravis are correct EXCEPT
(A) diplopia and ptosis are common signs
(B) muscle use results in fatigue
(C) this autoimmune syndrome occurs in the presence of antibodies to the muscarinic acetylcholine (ACh) receptors
(D) this condition results in nasal speech,dysarthria, and jaw fatigue
(E) this condition may be diagnosed usingedrophonium (Tensilon)
2-C. Muscarinic acetylcholine (ACh) receptors are not involved in myasthenia gravis. Autoantibodies are directed against nicotinic ACh receptors on the skeletal muscle and block the ACh binding site. Extraocular muscle is most commonly involved in myasthenia gravis, resulting in ptosis and double vision. Muscle use results in fatigue. (In Lambert-Eaton myasthenic syndrome, muscle use leads to decreased muscle fatigue.) Involvement of the bulbar muscles results in dysarthria, dysphonia, and dysphasia. The proximal limbs are weaker, and the distal limbs are stronger. Edrophonium (Tensilon), a cholinesterase inhibitor, can be used to diagnose myasthenia gravis.
- All of the following statements concerning acetylcholine (ACh) are correct EXCEPT
(A) it is the major transmitter of the peripheral nervous system
(B) it is found in high concentrations in the striatum
(C) it is found in high concentrations in the basal nucleus of Meynert
(D) its levels are increased in Alzheimer disease
(E) it is the involved neurotransmitter in myasthenia gravis
3-D. Acetylcholine (ACh) is the major transmitter of the peripheral nervous system (PNS). It is found in high concentrations in the striatum (caudate nucleus and putamen) and in the basal nucleus of Meynert. Striatal ACh-containing neurons are local circuit neurons. Cholinergic neurons from the basal nucleus project to the entire neocortex. Choline acetyltransferase levels are reduced in Alzheimer disease. In myasthenia gravis, an autoimmune syndrome, there is a decrease in the number of ACh-receptor sites in the postsynaptic membrane.
- All of the following statements concerning dopamine are correct EXCEPT
(A) dopaminergic neurons are found chiefly in the midbrain
(B) dopaminergic terminals are found chiefly in the striatum
(C) dopaminergic fibers are found in the tuberohypophyseal pathway
(D) dopamine contains an indole nucleus
(E) dopamine is a catecholamine
4-D. Dopaminergic neurons are found chiefly in the midbrain (the pars compacta of the substantia nigra and the ventral tegmental area of Tsai). Dopamine is a monoamine and a catecholamine. The tuberohypophyseal tract contains dopaminergic axons from the arcuate nucleus of the hypothalamus. Dopamine inhibits the release of prolactin from the adenohypophysis. The indole nucleus is found in serotonin.
- All of the following statements concerning the locus ceruleus are correct EXCEPT
(A) it is a mesencephalic structure
(B) it contains noradrenergic neurons
(C) it contains dopamine 3-hydroxylase
(D) its projections are limited to the cerebellar cortex
(E) it is a pontine structure
5-D. The locus ceruleus is located in the midbrain and rostral pons and contains noradrenergic neurons. The noradrenergic neurons contain the enzyme dopamine ^-hydroxylase, which synthesizes noradrenaline from dopamine. The locus ceruleus projects to the entire brain, the cerebellum, and large parts of the brainstem and spinal cord; it contains the largest concentrations of noradrenergic neurons in the brain. There is a substantial loss of neurons in the locus ceruleus in Alzheimer disease and Parkinson disease.
6. All of the following statements concerning serotonergic neurons are correct EXCEPT (A) they are found in the raphe nuclei (B) they are found in the cerebellum (C) they innervate the basal ganglia (D) they innervate the cerebellum (E) they contain tryptophan hydroxylase
6-B. Serotonergic [5-hydroxytryptamine (5-HT)-containing] neurons are found in the raphe nuclei and contain tryptophan hydroxylase, which catalyzes the conversion of tryptophan to 5-hydroxytryptophan, the immediate precursor of 5-HT. The caudate nucleus and putamen (basal ganglia) and cerebellum are innervated by 5-HT cells of the raphe nuclei. Serotonergic neurons are found only in the raphe nuclei of the brainstem.
- All of the following statements concerning somatostatin are correct EXCEPT
(A) it is found in dorsal root ganglion cells
(B) it is found in the hypothalamus
(C) it is an endorphin
(D) it is reduced in patients with Alzheimer disease
(E) it regulates the release of growth hormone (GH) and thyroid-stimulating hormone (TSH) from the hypophysis
7-C. Somatostatin (somatotropin release-inhibiting hormone), a cyclic peptide, is found in dorsal root ganglia and in the anterior hypothalamus. Somatostatin is a growth hormone (GH) inhibiting hormone that is released into the hypophyseal portal system. Somatostatin concentration in the neocortex and hippocampus is significantly reduced in patients with Alzheimer disease.
- All of the following statements concerning substance P are correct EXCEPT
(A) it is found in the striatopallidal and striatonigral tracts
(B) it is contained in dorsal root ganglion cells
(C) it is produced in neurons of the raphe nuclei
(D) it plays a role in pain transmission
(E) it is a powerful inhibitory neurotransmitter
8-E. Substance P is a powerful excitatory neurotransmitter that plays a role in pain transmission. The small nociceptive dorsal root ganglion cells use substance P. Raphe nuclei have been found to produce both serotonin (5-HT) and substance P. Substance P is also produced in striatal neurons (the caudate nucleus and the putamen), which project to the globus pallidus and the substantia nigra.
Questions 9-27 The response options for items 9-27 are the same. You will be required to select one answer for each item in the set. (A) Acetylcholine (ACh) (B) Aspartate (C) (^-Endorphin (D) Dopamine (E) Endorphin (F) Enkephalin (G) Epinephrine (H) Gamma-aminobutyric acid (GABA) (I) Glutamate (J) Glycine (K) Nitric oxide (L) Norepinephrine (M) Serotonin (N) Somatostatin (0) Substance P Match each of the statements with the neurotransmitter it best describes.
- Its highest concentration is found in thepineal gland
9-M. The highest concentration of serotonin is found in the pineal body (epiphysis cerebri).Pinealocytes convert 5-hydroxytryptamine (5-HT) to melatonin.
Questions 9-27 The response options for items 9-27 are the same. You will be required to select one answer for each item in the set. (A) Acetylcholine (ACh) (B) Aspartate (C) (^-Endorphin (D) Dopamine (E) Endorphin (F) Enkephalin (G) Epinephrine (H) Gamma-aminobutyric acid (GABA) (I) Glutamate (J) Glycine (K) Nitric oxide (L) Norepinephrine (M) Serotonin (N) Somatostatin (0) Substance P Match each of the statements with the neurotransmitter it best describes. 10. Is found in pseudounipolar ganglion cells and in the substantia gelatinosa
10-O. Substance P is the neurotransmitter of pain fibers and is found in pseudounipolar ganglion cells and in the substantia gelatinosa of the spinal cord. Substance P is also found in the caudal spinal trigeminal tract.
Questions 9-27 The response options for items 9-27 are the same. You will be required to select one answer for each item in the set. (A) Acetylcholine (ACh) (B) Aspartate (C) (^-Endorphin (D) Dopamine (E) Endorphin (F) Enkephalin (G) Epinephrine (H) Gamma-aminobutyric acid (GABA) (I) Glutamate (J) Glycine (K) Nitric oxide (L) Norepinephrine (M) Serotonin (N) Somatostatin (0) Substance P Match each of the statements with the neurotransmitter it best describes. 11. Is responsible for the smooth muscle relaxation of the corpus cavernosum and thus penile erection
11-K. Nitric oxide is responsible for the smooth muscle relaxation of the corpus cavernosum and thus penile erection.
Questions 9-27 The response options for items 9-27 are the same. You will be required to select one answer for each item in the set. (A) Acetylcholine (ACh) (B) Aspartate (C) (^-Endorphin (D) Dopamine (E) Endorphin (F) Enkephalin (G) Epinephrine (H) Gamma-aminobutyric acid (GABA) (I) Glutamate (J) Glycine (K) Nitric oxide (L) Norepinephrine (M) Serotonin (N) Somatostatin (0) Substance P Match each of the statements with the neurotransmitter it best describes. 12. Is produced by neurons found in the locus ceruleus
12-L. The highest concentration of norepinephrinergic neurons is found in the locus ceruleus
Questions 9-27 The response options for items 9-27 are the same. You will be required to select one answer for each item in the set. (A) Acetylcholine (ACh) (B) Aspartate (C) (^-Endorphin (D) Dopamine (E) Endorphin (F) Enkephalin (G) Epinephrine (H) Gamma-aminobutyric acid (GABA) (I) Glutamate (J) Glycine (K) Nitric oxide (L) Norepinephrine (M) Serotonin (N) Somatostatin (0) Substance P Match each of the statements with the neurotransmitter it best describes. 13. Is the neurotransmitter of the corticostriatal pathway
13-1. Glutamate is the neurotransmitter of the corticostriatal pathway.
Questions 9-27 The response options for items 9-27 are the same. You will be required to select one answer for each item in the set. (A) Acetylcholine (ACh) (B) Aspartate (C) (^-Endorphin (D) Dopamine (E) Endorphin (F) Enkephalin (G) Epinephrine (H) Gamma-aminobutyric acid (GABA) (I) Glutamate (J) Glycine (K) Nitric oxide (L) Norepinephrine (M) Serotonin (N) Somatostatin (0) Substance P Match each of the statements with the neurotransmitter it best describes. 14. Is produced by neurons of the raphe nuclei
14-M. Serotonin is produced by neurons of the raphe nuclei.
Questions 9-27 The response options for items 9-27 are the same. You will be required to select one answer for each item in the set. (A) Acetylcholine (ACh) (B) Aspartate (C) (^-Endorphin (D) Dopamine (E) Endorphin (F) Enkephalin (G) Epinephrine (H) Gamma-aminobutyric acid (GABA) (I) Glutamate (J) Glycine (K) Nitric oxide (L) Norepinephrine (M) Serotonin (N) Somatostatin (0) Substance P Match each of the statements with the neurotransmitter it best describes. 15. Is the neurotransmitter of the climbing fibers of the cerebellum
15-B. Aspartate is the neurotransmitter of the climbing fibers of the cerebellum.