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Questions and Answers
What may result from exposure to a toxin causing high blood pressure resulting in cardiac hypertrophy?
What may result from exposure to a toxin causing high blood pressure resulting in cardiac hypertrophy?
What is the result of Na+ Channel Blockade?
What is the result of Na+ Channel Blockade?
What may xenobiotic-induced constriction of the coronary vasculature result in?
What may xenobiotic-induced constriction of the coronary vasculature result in?
What is the consequence of inhibition of Na+, K+-ATPase?
What is the consequence of inhibition of Na+, K+-ATPase?
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What is the mechanism of action of K+ Channel Blockade?
What is the mechanism of action of K+ Channel Blockade?
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What may result in the production of toxic oxygen radicals, leading to subsequent tissue damage?
What may result in the production of toxic oxygen radicals, leading to subsequent tissue damage?
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What is the consequence of Ca2+ Channel Blockade?
What is the consequence of Ca2+ Channel Blockade?
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What is the result of interference with ion homeostasis?
What is the result of interference with ion homeostasis?
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What is the primary contractile unit in cardiac muscle tissue?
What is the primary contractile unit in cardiac muscle tissue?
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Which cells have limited proliferative capacity in the heart?
Which cells have limited proliferative capacity in the heart?
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What sets the pace of the heart's electrical conduction?
What sets the pace of the heart's electrical conduction?
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What records electrical currents of the heart?
What records electrical currents of the heart?
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What regulates cardiac activity by stimulating cardiac rate and contractility?
What regulates cardiac activity by stimulating cardiac rate and contractility?
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What is the crucial role played by the ATPase sarcoplasmic reticulum pump (SERCA) in cardiac myocytes?
What is the crucial role played by the ATPase sarcoplasmic reticulum pump (SERCA) in cardiac myocytes?
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What is the measurement of cardiac output (CO) dependent on?
What is the measurement of cardiac output (CO) dependent on?
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What may toxicants affect in the cardiovascular system?
What may toxicants affect in the cardiovascular system?
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What may result from disturbances in cardiac function?
What may result from disturbances in cardiac function?
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What is the result of interference with ion homeostasis in the heart?
What is the result of interference with ion homeostasis in the heart?
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What is the overview of the ventricular action potential (AP) in the heart?
What is the overview of the ventricular action potential (AP) in the heart?
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Which cells are involved in electrical conduction in the heart?
Which cells are involved in electrical conduction in the heart?
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Which part of the eye has a high number of Na+,K+-ATPase sites and can be affected by digoxin?
Which part of the eye has a high number of Na+,K+-ATPase sites and can be affected by digoxin?
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Which toxicant disrupts oxidative phosphorylation in rod and cone photoreceptors?
Which toxicant disrupts oxidative phosphorylation in rod and cone photoreceptors?
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What part of the eye does carbon disulfide affect, causing optic atrophy and depressed visual sensitivity?
What part of the eye does carbon disulfide affect, causing optic atrophy and depressed visual sensitivity?
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Which toxicant may result in structural, biochemical, and functional deficits in the visual cortex in addition to retinal effects?
Which toxicant may result in structural, biochemical, and functional deficits in the visual cortex in addition to retinal effects?
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What is the primary barrier to percutaneous absorption in the skin?
What is the primary barrier to percutaneous absorption in the skin?
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Which type of contact dermatitis accounts for over 90% of reported causes?
Which type of contact dermatitis accounts for over 90% of reported causes?
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Which enzyme in the skin contributes to its barrier function by metabolizing agents as diffusion occurs?
Which enzyme in the skin contributes to its barrier function by metabolizing agents as diffusion occurs?
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What is the major component of the skin that constitutes 90% of its composition?
What is the major component of the skin that constitutes 90% of its composition?
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What is the consequence of prolonged immersion on the effectiveness of the stratum corneum as a barrier?
What is the consequence of prolonged immersion on the effectiveness of the stratum corneum as a barrier?
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Which anatomical site displays faster diffusion through the epidermis than others?
Which anatomical site displays faster diffusion through the epidermis than others?
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Which toxicant causes tunnel vision and damages a portion of the visual cortex involving the peripheral visual field?
Which toxicant causes tunnel vision and damages a portion of the visual cortex involving the peripheral visual field?
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Which part of the eye consists of retinal cells that carry information from the retina to the CNS?
Which part of the eye consists of retinal cells that carry information from the retina to the CNS?
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Which part of the eye is highly vulnerable to toxicant-induced damage?
Which part of the eye is highly vulnerable to toxicant-induced damage?
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What may cause a decrease in the optical transparency of the lens?
What may cause a decrease in the optical transparency of the lens?
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Which substance may react with proteins in the lens, producing adducts that act as light scattering complexes?
Which substance may react with proteins in the lens, producing adducts that act as light scattering complexes?
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What is the transparent body in the eye that focuses visual images on the retina?
What is the transparent body in the eye that focuses visual images on the retina?
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Which medication, administered for schizophrenia, may combine with melanin to form a photosensitive product that reacts with sunlight?
Which medication, administered for schizophrenia, may combine with melanin to form a photosensitive product that reacts with sunlight?
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What may result from exposure to solvent vapors?
What may result from exposure to solvent vapors?
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What is the primary target site for organic solvents that are lipophilic?
What is the primary target site for organic solvents that are lipophilic?
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Which environmental factor may lead to the yellow coloration of the lens?
Which environmental factor may lead to the yellow coloration of the lens?
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What may cause irreversible loss of retinal function and blurred vision?
What may cause irreversible loss of retinal function and blurred vision?
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Which substance may penetrate both the aqueous and lipid layers of the cornea and may be irritating?
Which substance may penetrate both the aqueous and lipid layers of the cornea and may be irritating?
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What may lead to the production of toxic oxygen radicals, subsequently causing tissue damage?
What may lead to the production of toxic oxygen radicals, subsequently causing tissue damage?
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What may cause damage to the corneal epithelium and repair likely over a few days?
What may cause damage to the corneal epithelium and repair likely over a few days?
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What are the three layers of the tear film?
What are the three layers of the tear film?
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Which layer of the cornea acts as the external barrier to the internal ocular structures?
Which layer of the cornea acts as the external barrier to the internal ocular structures?
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What are the layers of the cornea?
What are the layers of the cornea?
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Which part of the eye includes uveal and retinal vessels with distinct properties?
Which part of the eye includes uveal and retinal vessels with distinct properties?
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What can influence toxicity by binding certain substances in the eye?
What can influence toxicity by binding certain substances in the eye?
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What type of enzymes are involved in ocular drug metabolism?
What type of enzymes are involved in ocular drug metabolism?
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What governs the penetration of toxic compounds into the visual areas of the CNS?
What governs the penetration of toxic compounds into the visual areas of the CNS?
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Which methods are used for the evaluation of ocular irritancy and toxicity?
Which methods are used for the evaluation of ocular irritancy and toxicity?
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What does the cornea provide for the eye?
What does the cornea provide for the eye?
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What can cause varying degrees of damage to the cornea, iris, ciliary body, and lens?
What can cause varying degrees of damage to the cornea, iris, ciliary body, and lens?
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What is the primary Ca$^{2+}$ regulatory organelle in cardiac myocytes?
What is the primary Ca$^{2+}$ regulatory organelle in cardiac myocytes?
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Which toxin may compromise ATP production by affecting oxidative phosphorylation of ADP in the mitochondria?
Which toxin may compromise ATP production by affecting oxidative phosphorylation of ADP in the mitochondria?
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Which cardiotoxin inhibits Na$^+$, K$^+$-ATPase, leading to an increase in available intracellular Ca$^{2+}$ for contraction?
Which cardiotoxin inhibits Na$^+$, K$^+$-ATPase, leading to an increase in available intracellular Ca$^{2+}$ for contraction?
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Which substance acts as a local anesthetic, decreases depolarization rate, slows conduction speed, and promotes arrhythmias?
Which substance acts as a local anesthetic, decreases depolarization rate, slows conduction speed, and promotes arrhythmias?
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What may halogenated alkanes cause due to their highly lipophilic nature and ability to cross the blood-brain barrier?
What may halogenated alkanes cause due to their highly lipophilic nature and ability to cross the blood-brain barrier?
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What is the primary role of vascular endothelial cells in the regulation of vascular tone and angiogenesis?
What is the primary role of vascular endothelial cells in the regulation of vascular tone and angiogenesis?
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What is the primary mechanism of action of tricyclic antidepressants on cardiac myocytes and Purkinje fibers?
What is the primary mechanism of action of tricyclic antidepressants on cardiac myocytes and Purkinje fibers?
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What is the primary effect of antipsychotic agents on cardiovascular function?
What is the primary effect of antipsychotic agents on cardiovascular function?
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What is the primary effect of general anesthetics on cardiac output and contractility?
What is the primary effect of general anesthetics on cardiac output and contractility?
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What is the consequence of halothane (anesthetic) blocking Ca$^{2+}$ channels in the cardiovascular system?
What is the consequence of halothane (anesthetic) blocking Ca$^{2+}$ channels in the cardiovascular system?
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What may result from exposure to a toxin causing high blood pressure and ventricular hypertrophy?
What may result from exposure to a toxin causing high blood pressure and ventricular hypertrophy?
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What is atherosclerosis characterized by?
What is atherosclerosis characterized by?
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What may result from exposure to excessive vasoconstrictors?
What may result from exposure to excessive vasoconstrictors?
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What can toxicant exposure result in?
What can toxicant exposure result in?
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What are common mechanisms of vascular toxicity?
What are common mechanisms of vascular toxicity?
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What do vasculotoxic agents like nicotine and cocaine cause?
What do vasculotoxic agents like nicotine and cocaine cause?
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How does 1,3-Butadiene increase the incidence of cardiac hemangiosarcomas?
How does 1,3-Butadiene increase the incidence of cardiac hemangiosarcomas?
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What do all toxicants absorbed into the circulatory system contact before reaching other body sites?
What do all toxicants absorbed into the circulatory system contact before reaching other body sites?
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What may chemically induced disturbances in cardiac function affect?
What may chemically induced disturbances in cardiac function affect?
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What may exposure to toxic chemicals and systemic drugs result in?
What may exposure to toxic chemicals and systemic drugs result in?
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What is the first site of action for exposure to the eye and visual system?
What is the first site of action for exposure to the eye and visual system?
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What is the primary change in vessel wall in atherosclerosis?
What is the primary change in vessel wall in atherosclerosis?
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What is the result of exposure to vasculotoxic agents like nicotine and cocaine?
What is the result of exposure to vasculotoxic agents like nicotine and cocaine?
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Study Notes
Cardiac Physiology and Function
- The cardiovascular system consists of the myocardium and a network of vascular vessels (arteries, capillaries, veins) that supply cells and tissues with nutrients and remove waste products.
- The primary contractile unit in cardiac muscle tissue is the cardiac muscle cell (myocyte), which is joined by tight gap junctions facilitating action potential propagation.
- The heart comprises various cellular phenotypes, including myocytes, cardiac fibroblasts, vascular cells, Purkinje cells, and connective tissue cells, with limited proliferative capacity of myocytes and promotion of cardiac fibroblast proliferation.
- The ventricular action potential (AP) overview involves different phases, including resting, initiation, plateau, and re-polarization, with specific ion channels opening and closing during each phase.
- Electrical conduction in the heart involves pacemaker cells such as the sinoatrial (SA) node, atrioventricular (AV) node, bundle of His, and Purkinje fibers, with the SA node commonly setting the pace of the heart.
- The electrical impulse migration from the SA node through the atrial muscle, AV node, and bundle of His allows atria to fully contract before ventricles depolarize.
- An electrocardiogram (ECG) records electrical currents of the heart, with different intervals corresponding to conduction through the AV node, ventricular depolarization and repolarization.
- Cardiac activity is regulated by the autonomic nervous system (ANS), with sympathomimetics stimulating cardiac rate and contractility, and parasympathomimetics decreasing the rate of depolarization.
- Excitation-contraction coupling in cardiac myocytes involves the availability of ATP and Ca2+ for contraction and relaxation, with the ATPase sarcoplasmic reticulum pump (SERCA) playing a crucial role.
- Cardiac function is characterized by the recording of electrical currents through an ECG and the measurement of cardiac output (CO) which is dependent on heart rate and stroke volume, typically around 5L/min.
- Toxicants can affect cardiac function through their effects on the heart, vasculature, and/or the nervous system, potentially leading to disturbances in heart rhythm, such as arrhythmias.
- Disturbances in cardiac function may include abnormal heart rhythm, ischemic heart disease, cardiac hypertrophy, and heart failure, with potential implications for myocardial infarction, scar tissue formation, and reduced cardiac output.
Disturbances of Vascular Structure and Function
- Atherosclerosis is a change in the vessel wall involving focal intimal thickenings following smooth muscle cell migration and uncontrolled proliferation, leading to plaque formation and vascular narrowing.
- Hypertension may result from exposure to excessive vasoconstrictors, causing ventricular hypertrophy, atherosclerosis, capillary destruction, and increased vascular permeability.
- Toxicant exposure can result in thrombosis, forming semisolid masses in veins and arteries, which may detach as emboli in smaller vessels.
- Exposure to chemicals through major routes affects vascular cells before other body sites, increasing the risk of toxic insult.
- Common mechanisms of vascular toxicity include alterations in membrane structure and function, redox stress, vessel-specific bioactivation of protoxicants, and accumulation of active toxins in vascular cells.
- Vasculotoxic agents like nicotine, cocaine, and heavy metals can increase heart rate, blood pressure, and cause vasoconstriction.
- 1,3-Butadiene, used in rubber and automobile part production, increases the incidence of cardiac hemangiosarcomas through bioactivation by cytochrome p450.
- All toxicants absorbed into the circulatory system contact vascular cells before reaching other body sites.
- Chemically induced disturbances in cardiac function may affect heart rate, contractility, conductivity, and excitability.
- Exposure to toxic chemicals, vapors, or therapeutic drugs can result in structural and functional alterations in the eye and visual system.
- Toxic chemicals and systemic drugs may affect all parts of the eye, including the cornea, conjunctiva, and eyelids.
- Tear film, with both hydrophobic and hydrophilic properties, is the first site of action for exposure to the eye and visual system.
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Description
Test your knowledge of cardiac physiology and function with this quiz. Explore topics such as cardiac muscle cells, ventricular action potential, electrical conduction in the heart, electrocardiogram interpretation, autonomic nervous system regulation, and cardiac function assessment. Brush up on toxicant effects and disturbances in cardiac function.
