Question 1

A neoplasm considered to be a pediatric cancer that is derived from the neural crest cells of the sympathetic nervous system is referred to as a:

Accepted Answer

A)  pheochromocytoma. 
B)  gastroenteropancreatic neuroendocrine tumor. 
C)  neuroblastoma. 
D)  carcinoid tumor. 
A)  pheochromocytoma. 
B)  gastroenteropancreatic neuroendocrine tumor. 
C)  neuroblastoma. 
D)  carcinoid tumor. C

Question 2

In the assessment of equivocal results in pheochromocytoma testing,the clonidine suppression test is used to differentiate between:

Accepted Answer

A)  elevated blood pressure caused by pheochromocytoma versus that caused by carcinoid tumor. 
B)  increased serotonin production by the GI tract versus serotonin from the brain. 
C)  adrenal gland and GI tract increased synthesis of dopamine. 
D)  adrenal gland and sympathetic nervous system increases in catecholamine synthesis. 
A)  elevated blood pressure caused by pheochromocytoma versus that caused by carcinoid tumor. 
B)  increased serotonin production by the GI tract versus serotonin from the brain. 
C)  adrenal gland and GI tract increased synthesis of dopamine. 
D)  adrenal gland and sympathetic nervous system increases in catecholamine synthesis. D

Question 3

In the gastrointestinal (GI)tract,dopamine functions as a modulator of the enteric nervous system or as a paracrine substance.What essential enzyme is required for synthesis of dopamine in the dopaminergic system in the GI tract?

Accepted Answer

A)  Tryptophan hydroxylase 
B)  Tyrosine hydroxylase 
C)  Catechol-O-methyltransferase (COMT) 
D)  Monoamine oxidase (MAO) 
A)  Tryptophan hydroxylase 
B)  Tyrosine hydroxylase 
C)  Catechol-O-methyltransferase (COMT) 
D)  Monoamine oxidase (MAO) B

Question 4

MATCHING
Match the disorder with the diagnostic analyte measured in the laboratory.
-Urinary 5-HIAA

Accepted Answer

A) Gastroenteropancreatic endocrine tumor 
B) Tumor of adrenal medullary chromaffin cells 
C) Pineal gland tumor 
D) Neuroblastoma 
A) Gastroenteropancreatic endocrine tumor 
B) Tumor of adrenal medullary chromaffin cells 
C) Pineal gland tumor 
D) Neuroblastoma

Question 5

In the diagnosis of pheochromocytoma,what hormone is being assessed by measuring urine metanephrine?

Accepted Answer

A)  Epinephrine 
B)  Dopamine 
C)  Serotonin 
D)  Norepinephrine 
A)  Epinephrine 
B)  Dopamine 
C)  Serotonin 
D)  Norepinephrine

Question 6

The amino acid precursor for the neurotransmitter serotonin (5HT)is:

Accepted Answer

A)  tyrosine. 
B)  tryptophan. 
C)  threonine. 
D)  cytosine. 
A)  tyrosine. 
B)  tryptophan. 
C)  threonine. 
D)  cytosine.

Question 7

A man visits his physician complaining of hypertension (elevated heart rate and blood pressure),periodic bouts of profuse sweating,and occasional severe headaches.These symptoms are indicative of:

Accepted Answer

A)  Cushing syndrome. 
B)  carcinoid syndrome. 
C)  pheochromocytoma. 
D)  neuroblastoma. 
A)  Cushing syndrome. 
B)  carcinoid syndrome. 
C)  pheochromocytoma. 
D)  neuroblastoma.

Question 8

The urinary metabolite measured as an indicator of dopamine synthesis is:

Accepted Answer

A)  metanephrine. 
B)  homovanillic acid. 
C)  vanillylmandelic acid. 
D)  catechol-O-methyltransferase. 
A)  metanephrine. 
B)  homovanillic acid. 
C)  vanillylmandelic acid. 
D)  catechol-O-methyltransferase.

Question 9

MATCHING
Match the disorder with the diagnostic analyte measured in the laboratory.
-Urinary VMA

Accepted Answer

A) Gastroenteropancreatic endocrine tumor 
B) Tumor of adrenal medullary chromaffin cells 
C) Pineal gland tumor 
D) Neuroblastoma 
A) Gastroenteropancreatic endocrine tumor 
B) Tumor of adrenal medullary chromaffin cells 
C) Pineal gland tumor 
D) Neuroblastoma

Question 10

Currently,the most common method of analysis for plasma catecholamines is:

Accepted Answer

A)  liquid chromatography (L
C) with electrochemical (E
C) detection. 
B)  HPLC. 
C)  mass spectrometry. 
D)  spectrophotometry. 
A)  liquid chromatography (L
C) with electrochemical (E
C) detection. 
B)  HPLC. 
C)  mass spectrometry. 
D)  spectrophotometry.

Question 11

The rate-limiting step in the biosynthesis of catecholamines is the:

Accepted Answer

A)  conversion of 3-methoxy-4-hydroxyphenylglycol (MHPG)to VMA by alcohol dehydrogenase. 
B)  conversion of tryptophan to 5-hydroxytryptophan by tryptophan hydroxylase. 
C)  metabolism by catechol-O-methyltransferase (COMT)to MHPG. 
D)  conversion of tyrosine to 3,4-dihydroxyphenylalanine by tyrosine hydroxylase. 
A)  conversion of 3-methoxy-4-hydroxyphenylglycol (MHPG)to VMA by alcohol dehydrogenase. 
B)  conversion of tryptophan to 5-hydroxytryptophan by tryptophan hydroxylase. 
C)  metabolism by catechol-O-methyltransferase (COMT)to MHPG. 
D)  conversion of tyrosine to 3,4-dihydroxyphenylalanine by tyrosine hydroxylase.

Question 12

Which one of the following substances is measured in urine to determine the presence of a gastroenteropancreatic neuroendocrine tumor in an individual with carcinoid syndrome?

Accepted Answer

A)  VMA 
B)  Metanephrine 
C)  Homovanillic acid (HV
A)  
D)  5-Hydroxyindole acetic acid (5-HIA
A)  
A)  VMA 
B)  Metanephrine 
C)  Homovanillic acid (HV
A)  
D)  5-Hydroxyindole acetic acid (5-HIA
A)

Question 13

Regarding catecholamines,the amino acid from which dopamine is synthesized?

Accepted Answer

A)  Threonine 
B)  Tryptophan 
C)  Tyrosine 
D)  Cytosine 
A)  Threonine 
B)  Tryptophan 
C)  Tyrosine 
D)  Cytosine

Question 14

MATCHING
Match the disorder with the diagnostic analyte measured in the laboratory.
-Melatonin

Accepted Answer

A) Gastroenteropancreatic endocrine tumor 
B) Tumor of adrenal medullary chromaffin cells 
C) Pineal gland tumor 
D) Neuroblastoma 
A) Gastroenteropancreatic endocrine tumor 
B) Tumor of adrenal medullary chromaffin cells 
C) Pineal gland tumor 
D) Neuroblastoma

Question 15

An overnight fast is recommended for individuals being tested for carcinoid syndrome because:

Accepted Answer

A)  dietary interference,particularly with foods that contain 5-hydroxyindoles,will produce a false increase in plasma 5-HIAA measurement. 
B)  no food should be present in the GI tract for 12 hours before analysis of catecholamine metabolites. 
C)  monoamine systems are targets of certain components of foods that contain tyrosine,and a false-negative result will occur in HVA testing. 
D)  certain foods interfere with the methods of analysis used for serotonin analysis,particularly the high performance liquid chromatography (HPL
C) assays. 
A)  dietary interference,particularly with foods that contain 5-hydroxyindoles,will produce a false increase in plasma 5-HIAA measurement. 
B)  no food should be present in the GI tract for 12 hours before analysis of catecholamine metabolites. 
C)  monoamine systems are targets of certain components of foods that contain tyrosine,and a false-negative result will occur in HVA testing. 
D)  certain foods interfere with the methods of analysis used for serotonin analysis,particularly the high performance liquid chromatography (HPL
C) assays.

Question 16

Measurement of urinary metanephrine and vanillylmandelic acid (VMA)assesses the amount of hormone secreted by the _____ and is done to detect the presence of _____.

Accepted Answer

A)  gastrointestinal (GI)tract; carcinoid tumor 
B)  adrenal medulla; pheochromocytoma 
C)  adrenal cortex; Cushing syndrome 
D)  medulla of the brain; neuroblastoma 
A)  gastrointestinal (GI)tract; carcinoid tumor 
B)  adrenal medulla; pheochromocytoma 
C)  adrenal cortex; Cushing syndrome 
D)  medulla of the brain; neuroblastoma

Question 17

All of the following represent metabolic effects caused by the action of epinephrine secreted from the adrenal gland except:

Accepted Answer

A)  increased lipolysis. 
B)  bronchodilation. 
C)  increased protein synthesis. 
D)  glycogenolysis. 
A)  increased lipolysis. 
B)  bronchodilation. 
C)  increased protein synthesis. 
D)  glycogenolysis.

Question 18

In the sympathetic component of the autonomic nervous system,norepinephrine acts to:

Accepted Answer

A)  increase heart rate and blood pressure. 
B)  induce hypotension. 
C)  dilate the peripheral blood vessels. 
D)  increase the release of serotonin from the brain. 
A)  increase heart rate and blood pressure. 
B)  induce hypotension. 
C)  dilate the peripheral blood vessels. 
D)  increase the release of serotonin from the brain.

Question 19

Metabolism of norepinephrine and epinephrine in adrenal chromaffin cells requires the presence of which one of the following enzymes for conversion into normetanephrine and metanephrine?

Accepted Answer

A)  Catechol-O-methyltransferase 
B)  Dopamine-$\beta$-hydroxylase 
C)  Tyrosine hydroxylase 
D)  Monoamine oxidase 
A)  Catechol-O-methyltransferase 
B)  Dopamine-$\beta$-hydroxylase 
C)  Tyrosine hydroxylase 
D)  Monoamine oxidase

Question 20

Dopamine in the central nervous system functions as a neurotransmitter important for regulating an overall state of attention and vigilance.

Accepted Answer

A) True 
 B)False

Exam 26: Catecholamines and Serotonin

A neoplasm considered to be a pediatric cancer that is derived from the neural crest cells of the sympathetic nervous system is referred to as a:

In the assessment of equivocal results in pheochromocytoma testing,the clonidine suppression test is used to differentiate between:

In the gastrointestinal (GI)tract,dopamine functions as a modulator of the enteric nervous system or as a paracrine substance.What essential enzyme is required for synthesis of dopamine in the dopaminergic system in the GI tract?

MATCHING Match the disorder with the diagnostic analyte measured in the laboratory. -Urinary 5-HIAA

In the diagnosis of pheochromocytoma,what hormone is being assessed by measuring urine metanephrine?

The amino acid precursor for the neurotransmitter serotonin (5HT)is:

A man visits his physician complaining of hypertension (elevated heart rate and blood pressure),periodic bouts of profuse sweating,and occasional severe headaches.These symptoms are indicative of:

The urinary metabolite measured as an indicator of dopamine synthesis is:

MATCHING Match the disorder with the diagnostic analyte measured in the laboratory. -Urinary VMA

Currently,the most common method of analysis for plasma catecholamines is:

The rate-limiting step in the biosynthesis of catecholamines is the:

Which one of the following substances is measured in urine to determine the presence of a gastroenteropancreatic neuroendocrine tumor in an individual with carcinoid syndrome?

Regarding catecholamines,the amino acid from which dopamine is synthesized?

MATCHING Match the disorder with the diagnostic analyte measured in the laboratory. -Melatonin

An overnight fast is recommended for individuals being tested for carcinoid syndrome because:

Measurement of urinary metanephrine and vanillylmandelic acid (VMA)assesses the amount of hormone secreted by the _____ and is done to detect the presence of _____.

All of the following represent metabolic effects caused by the action of epinephrine secreted from the adrenal gland except:

In the sympathetic component of the autonomic nervous system,norepinephrine acts to:

Metabolism of norepinephrine and epinephrine in adrenal chromaffin cells requires the presence of which one of the following enzymes for conversion into normetanephrine and metanephrine?

Dopamine in the central nervous system functions as a neurotransmitter important for regulating an overall state of attention and vigilance.

Clinical Chemistry, molecular Diagnostics, and Laboratory Medicine

Selection and Analytical Evaluation of Methodswith Statistical Techniques

Clinical Evaluation of Methods

Evidence-Based Laboratory Medicine

Establishment and Use of Reference Values

Specimen Collection, processing, and Other Preanalytical Variables

Quality Management

Principles of Basic Techniques and Laboratory Safety

Optical Techniques

Electrochemistry and Chemical Sensors

Electrophoresis

Chromatography

Mass Spectrometry

Enzyme and Rate Analyses

Immunochemical Techniques

Automation

Point-Of-Care Instrumentation

Amino Acids, peptides, and Proteins

Serum Enzymes

Tumor Markers and Cancer Genes

Kidney Function Test-Screatinine, Urea, and Uric Acid

Carbohydrates

Lipids, lip-Oproteins, apolipoproteins, and Other Cardiac Risk Factors

Electrolytes and Blood Gases

Hormones

Vitamins, Trace Elements, and Nutritional Assessment

Hemoglobin, Iron, and Bilirubin

Porphyrins and Porphyrias

Therapeutic Drugs and Their Management

Clinical Toxicology

Toxic Metals

Diabetes

Cardiovascular Disease

Kidney Disease

Physiology and Disorders of Water,Electrolyte,and Acid-Base Metabolism

Liver Disease

Gastrointestinal and Pancreatic Diseases

Disorders of Bone and Mineral Metabolism

Disorders of the Pituitary

Disorders of the Adrenal Cortex

Thyroid Disorders

Reproduction-Related Disorders

Pregnancy and Prenatal Testing

Newborn Screening and Inborn Errors of Metabolism

Pharmacogenetics

Principles of Molecular Biology

Nucleic Acid Techniques and Applications

Genomes and Nucleic Acid Alterations

Filters

Measurement of urinary metanephrine and vanillylmandelic acid (VMA)assesses the amount of hormone secreted by the _ and is done to detect the presence of _.