Chapter 12 - Cardiovascular Toxicology Flashcards
All of the following positive ions are involved in the bioelectricity of the heart except…
A. Mg
B. Na
C. K
D. Ca
A. Mg
What is the resting potential of a cardiac myocyte relative to extracellular fluid?
A. -120 to -90 mV
B. -90 to -60 mV
C. -60 to -30 mV
D. -30 to -10 mV
B. -90 to -60 mV
The phase of the action potential during which there is rapid inward movement of sodium ions is called phase…
A. 0
B. 1
C. 2
D. 3
A. 0
The sinus node pacemaker cells and Purkinje fibers in the ventricles are examples of cardiac cells that have the property of…
A. Dedifferentiation
B. phagocytosis
C. Automaticity
D. Six phases of the action potential
C. Automaticity
Excitation-contraction coupling requires all of the following except…
A. Entry of extracellular calcium into the cell
B. hydrolysis of ATP
C. A conformational change in the cardiac myocyte thin filament
D. Binding of calcium to acid phosphatase
D. Binding of calcium to acid phosphatase
Contraction and relaxation of individual cardiac myocytes in an organized manner to perform efficient pump function is achieved by…
A. Neurohormonal regulation
B. neurotransmitter release
C. Electronic cell-to-cell coupling
D. Local release of cytokines
C. Electronic cell-to-cell coupling
The QRS segment of the electrocardiograph represents…
A. Atrial depolarization
B. conduction time through the ventricles
C. Ventrical repolarization
D. B and C
B. conduction time through the ventricles
A normal ST segment is…
A. Biphasic
B. elevated 2-3 mm from baseline
C. Depressed 2-3 mm from baseline
D. None of the above
D. None of the above
Which of the following molecules is responsible for the largest energy stores in the heart?
A. ATP
B. Creatine
C. Phosphocreatine
D. ADP
C. Phosphocreatine
During toxicant-induced damage to cardiac mitochondria, there is an energy shift to reliance on…
A. Oxidation of free fatty acids
B. Deamination of amino acids
C. ATP produced in the liver
D. Anaerobic glucose metabolism
D. Anaerobic glucose metabolism
All of the following are cellular events causing cardiomyopathy from toxicant exposure except…
A. Myocardial cell death
B. Myocyte hyperplasia
C. Extracellular matrix remodeling
D. Apoptosis
B. Myocyte hyperplasia
Which of the following is asso w/ heart hypertrophy rather than heart failure after toxicant exposure?
A. Fetal gene expression
B. apoptosis
C. Dilation
D. All of the above
A. Fetal gene expression
Factors that can convert cardiac hypertrophy into cardiac failure include all of the following except…
A. ANP
B. ET-1
C. TNF
D. angiotensin II inhibitors
D. angiotensin II inhibitors
Lethal cardiac arrhythmia has been asso w/ …
A. Maladaptive cardiac hypertrophy
B. QT prolongation
C. Myocardial infarction
D. All of the above
D. All of the above
A recent discovery that challenges the concept of the permanent loss of cardiac myocytes following cell death is the identification of…
A. Cardiac progenitor cells
B. Cytokines that inhibit apoptosis
C. Growth factors that stimulate hypertrophy
D. Cytokines that stimulate angiogenesis
A. Cardiac progenitor cells
A prolonged QTc interval in humans is considered greater than…
A. 400 ms
B. 420 ms
C. 460 ms
D. 500 ms
C. 460 ms
All of the following can prolong the QT interval except…
A. Genetic polymorphisms
B. Class III antiarrhythmics
C. Hyperkalemia
D. Exposure to particulate matter air polution
C. Hyperkalemia
A biomarker for inflammation that may predict future cardiac events in asymptomatic individuals is…
A. CK-MM
B. Myoglobin
C. BNP
D. C-reactive protein
D. C-reactive protein
One theory for arrhythmia secondary to cardiac hypertrophy is…
A. Unbalanced distribution of Purkinje fibers in the remodeling heart
B. Increase in intracellular Mg in hypertrophied cells
C. Increase in systolic blood pressure secondary to cardiac output
D. None of the above
A. Unbalanced distribution of Purkinje fibers in the remodeling heart
Besides alterations in potassium channels, long QT syndrome could result from dysfunctional…
A. Na channels
B. Cl channels
C. Glutamate channels
D. GABA channels
A. Na channels
At the cellular level, many toxicants cause cardiac toxicity by…
A. Increasing intracellular pH
B. Decreasing intracellular Ca
C. Stabilizing cardiac myocyte membranes
D. Increasing intracellular Ca
D. Increasing intracellular Ca