142 Questions
Which part of the lung is responsible for particle removal and airflow regulation?
Lung parenchyma acinus
What supports the first 12 generations of branches in the upper airways of the lung?
Rigid cartilage rings
Which part of the lung is responsible for extensive gas exchange?
Alveolar ducts and sacs
What is the origin of mesothelioma cancer?
From chronic inflammation in pleural lining
Who is at risk of developing mesothelioma?
Asbestos workers and their household contacts
What is the predominant cause of Small Cell Lung Carcinoma (SCLC)?
Smoking and occupational hazards like asbestos exposure
Where do Small Cell Lung Carcinoma (SCLC) cells originate from?
Kulchitzky cells in airway mucosa
What type of cancer is Small Cell Lung Carcinoma (SCLC)?
Non-epithelial lung cancer
What is pneumoconiosis?
Accumulation of mineral dust in the lungs
What are the occupations associated with pneumoconiosis?
Hard rock mining, quarrying, and coal mining
What is the distinguishing feature of Small Cell Lung Carcinoma (SCLC) cells?
Small sized cells resembling oat flakes
What is the severe form of acute lung injury (ALI)?
Acute (adult) respiratory distress syndrome (ARDS)
What is the main cause of ARDS?
Physical trauma or other life-threatening conditions
What is the primary consequence of alveolar collapse?
Reduced gas-exchange (hypoxia)
Which type of lung disease causes obstruction to airflow?
Chronic obstructive pulmonary disease (COPD)
What is the characteristic feature of ARDS lung gross anatomy?
Diffuse alveolar damage
What is the main cause of chronic obstructive pulmonary disease (COPD)?
Continuous exposure to airborne particulates
What is the primary consequence of upper airway irritants?
Acute painful irritation and chemical damage/burns to lung airways
What is the consequence of accumulation of edema fluid in the alveoli?
Interference with gas-exchange
What is the primary characteristic of restrictive lung diseases?
Alveolar thickening interferes with alveolar inflation
What is the primary consequence of exposure to lower airway irritants?
Severe inflammatory response
What is the main cause of chronic lung diseases?
Continuous exposure or repeated exposure over long time duration
What is the primary outcome of diffuse alveolar damage in the lung?
Rapid development of profound respiratory failure
What are the 2 basic types of asthma mentioned in the text?
Intrinsic asthma and extrinsic asthma
What type of response characterizes extrinsic asthma?
Type-1 immediate hypersensitivity response to an antigenic substance
What is the main characteristic of restrictive lung disease?
Progressive stiffening of lung parenchyma
What is the effect of interstitial fibrosis on lung compliance?
Greater effort required to inflate the lungs
What is a common presenting symptom of lung cancer?
Blood in sputum
Which type of lung cancer is more commonly found in heavy smokers?
Squamous cell carcinoma
From which type of tissue are adenocarcinomas of the lung derived?
Glandular epithelial tissue
What is the effect of interstitial thickening and scarring on gas exchange in the lungs?
Reduced gas exchange
What is the main risk factor for the development of asthma mentioned in the text?
Inflammation
What is the underlying process for bronchoconstriction in asthma?
Inflammatory processes
What is the main cause of the 'twitchy bronchus' in asthma?
Antigenic substance (allergen)
What is the primary prevention strategy for lung cancer mentioned in the text?
Removing major causes of lung cancer
What is the primary function of pulmonary alveolar macrophages?
Particle clearance and release of harmful enzymes and inflammatory cytokines
What can result from underproduction or inactivation of pulmonary surfactant?
Impaired lung function
What makes the lung particularly susceptible to air contaminants?
Large tidal volume of external air and branching/narrowing of airways
What can lead to the accumulation of excess mucus and bacterial growth in the lungs?
Loss of cilia from the mucociliary escalator
What is crucial for gas exchange in the alveolar wall?
Air:blood interface
What defense mechanism involves the movement of mucus out of the respiratory system?
Mucociliary escalator
What can result from abnormalities in ventilation:perfusion ratio?
Lung disease
What is the primary consequence of exposure to high concentrations of reactive oxygen species?
Lung damage
What is the most abundant component of lung volume?
Air-filled alveoli
What makes the lung vulnerable to air contaminants?
Branching and narrowing of airways
What can result from problems in lung functional anatomy?
Lung toxicity
What is the role of particle size in the respiratory system?
Influences where particles are deposited and affects their removal mechanisms
What is the primary pathological consequence of COPD related to lung airways?
Chronic mucosal inflammation and mucus hypersecretion
Which type of COPD is characterized by persistent breathlessness exacerbated by physical exertion and severely diminished lung functional reserve?
Emphysema (Type A)
What is the defining symptom of chronic bronchitis (Type B) in COPD?
Cough production of sputum on most days for a minimum 3 months over 2 consecutive years
What is the primary cause of COPD damage in smokers?
Cigarette smoke
What is the primary consequence of type A COPD (emphysema) in severe end-stage disease?
Hypoxia and hypercapnia
What is the main characteristic of bronchial asthma?
Transient reversible reduction in pulmonary airflow
What is the primary consequence of exposure to high dust levels in relation to COPD?
Increased vulnerability to COPD
What is the primary consequence of exposure to lower airway irritants?
Chronic mucosal inflammation in large and small airways
What is the primary pathological consequence of severe type B COPD (bronchitic)?
Cor pulmonale
What is the primary characteristic of restrictive lung diseases?
Reduced gas-exchange capacity
What is the primary consequence of alveolar collapse in the lungs?
Reduced gas-exchange capacity
What is the primary consequence of upper airway irritants in the lungs?
Labored breathing and shortness of breath
What is the main component of lung volume?
Air-filled alveoli
What makes the lung vulnerable to air contaminants?
Large tidal volume of external air and branching/narrowing of airways
What can lead to the accumulation of excess mucus and bacterial growth in the lung?
Loss of cilia from the mucociliary escalator
Which component plays a role in particle clearance and can release harmful enzymes and inflammatory cytokines?
Pulmonary alveolar macrophages
What can result from high exposure to corrosive or toxic agents, leading to damage to type-2 cells?
Acute respiratory distress syndrome
Which mechanism is essential for proper lung function and can be underproduced in premature infants or inactivated by acute lung injury?
Pulmonary surfactant
What is crucial for gas exchange in the lung, and abnormalities in its ratio can lead to lung disease?
Air:blood interface in the alveolar wall
What can lead to problems in lung functional anatomy, such as the need for specific cellular regeneration and repair after serious damage?
Lung toxicity
What plays a role in the removal of particles from the respiratory system, influenced by particle size?
Deposition mechanisms
Which defense mechanism in the lung can play a role in the release of harmful enzymes and inflammatory cytokines?
Pulmonary alveolar macrophages
What is particularly susceptible to air contaminants due to its special vulnerabilities?
Lung
What is the primary defense mechanism in the lung for filtering out particles from the air?
Aerodynamic filtration
Which is a primary symptom of chronic bronchitis in COPD?
Labored breathing and shortness of breath
What is the primary pathological consequence of severe type B COPD (bronchitic)?
Pulmonary hypertension
What is the primary characteristic of COPD Type A (emphysema) in severe end-stage disease?
Diminished lung functional reserve
What is the primary consequence of exposure to high dust levels in relation to COPD?
Increased vulnerability to COPD
What is the primary cause of COPD?
Cigarette smoke
What is the primary defense mechanism in the lung for filtering out particles from the air?
Mucociliary (MC) escalator
What is the defining symptom of chronic bronchitis (Type B) in COPD?
Cough production of sputum on most days for a minimum 3 months over 2 consecutive years
What is the primary consequence of exposure to lower airway irritants?
Chronic mucous hypersecretion
What is the primary characteristic of bronchial asthma?
Airway hyper-responsiveness to a specific eliciting factor
What is the primary pathological consequence of COPD?
Reduced gas-exchange capacity
What is the primary consequence of upper airway irritants in the lungs?
Mucus hypersecretion and accumulation
What can result from underproduction or inactivation of pulmonary surfactant?
Increased vulnerability to lung diseases
Which layer of the cornea accounts for 90% of its thickness?
Stroma
In which ocular structure are xenobiotic transforming enzymes found in all compartments?
Retina
Which vascular system possesses loose endothelial junctions and is highly permeable?
Choroidal Vessels
What is the primary barrier lacking at the optic nerve, allowing hydrophilic molecules to enter?
Blood-Retinal Barrier
In which layer of the retina are the rod and cone photoreceptor outer segments located?
RPE: Retinal pigment epith.
Where is intraocular melanin found?
Retina
Which part of the eye has the lowest capability of biotransformation?
Lens
What governs the penetration of toxic compounds into the visual areas of the CNS?
Blood-Brain Barrier
Which test is commonly used for the evaluation of ocular irritancy and toxicity?
Draize Test
Where are phase I and II xenobiotic transforming enzymes found in the eye?
All of the above
What is the role of the optic nerve in the penetration of toxic compounds into the visual areas of the CNS?
It has vesicular transport mechanisms
Which part of the eye has the highest capability of biotransformation?
Retina
What is the consequence of left-sided heart failure?
Pulmonary edema
What can lead to disturbances in heart rhythm?
Cardiac glycosides
What can result from xenobiotic-induced constriction of the coronary vasculature?
Ischemia
What is a potential consequence of exposure to certain toxins on organellar function?
Increased intracellular Ca2+
What can result from ethanol metabolites from chronic consumption?
Lipid peroxidation of cardiac myocytes
What is a potential effect of tricyclic antidepressants on cardiac myocytes and Purkinje fibers?
Depressing inward Na+ and Ca2+ and outward K+ currents
What is a potential consequence of general anesthetics on cardiac output and contractility?
Decrease in cardiac output and contractility
What is the potential consequence of vascular endothelial cell injury?
Vessel wall changes and plaque formation
What is a potential consequence of ischemia-reperfusion injury?
Production of toxic oxygen radicals
What can be a consequence of channel blockade in cardiotoxicity?
Reduction of conduction velocity
What can result from inhibition of Na+, K+-ATPase in cardiotoxicity?
Increased intracellular Na+ and elevated Ca2+
What is a potential consequence of cardiac glycosides like digoxin?
Arrhythmias and reduced resting membrane potential
Which of the following is a major hypothesis for atherosclerosis formation?
Chemical injury leading to platelet recruitment and smooth muscle cell migration
What are some common vasculotoxic agents mentioned in the text?
Nicotine, cocaine, heavy metals, and 1,3-butadiene
What is the first site of action for toxic chemicals and systemic drugs affecting the eye and visual system?
Tear film
What can result from environmental and occupational exposure to various toxins mentioned in the text?
Toxic responses of the visual system and skin
What are the mechanisms of vascular toxicity mentioned in the text?
Alterations in membrane structure and function, redox stress, and vessel-specific bioactivation of protoxicants
What can chemically induced disturbances in cardiac function consist of?
Effects on heart rate, contractility, conductivity, and excitability
Where do all toxicants absorbed into the circulatory system contact before reaching other body sites?
Vascular cells
What can exposure to toxic chemicals, vapors, or therapeutic drugs result in?
Structural and functional alterations in the eye and visual system
What is the primary consequence of disturbances of vascular structure and function from toxicant exposure?
Hypotension, hypertension, and thrombosis
What is the result of ocular absorption and distribution following topical exposure?
Affecting the cornea, conjunctiva, and eyelids
What can direct exposure to chemicals, gases, and particles affect in the eye?
All parts of the eye, leading to structural and functional alterations
What are the consequences of exposure to toxic chemicals, vapors, or therapeutic drugs?
Structural and functional alterations in the eye and visual system
Which cells serve as the heart's pacemaker?
SA and AV nodes
What is the primary role of cardiac fibroblasts in the heart?
Promoting proliferation after injury
Which phase is NOT part of the ventricular action potential?
Hyperpolarization
What is the significance of the PR interval on an electrocardiogram?
It reflects atrial depolarization and AV nodal delay
Which component is not directly involved in electrical conduction within the heart?
Cardiac fibroblasts
What is the main effect of sympathomimetics on cardiac function?
Stimulating cardiac rate and contractility
Which ions are crucial for excitation-contraction coupling in cardiac myocytes?
Ca2+ and ATP
What does cardiac output depend on?
Heart rate and stroke volume
Which condition is NOT a disturbance in cardiac function?
Myocyte hyperplasia
Which of the following is not a cellular phenotype found in the heart?
Neuronal cells
What can toxicants affect to alter cardiac output?
The heart, vasculature, and nervous system
Which interval on an electrocardiogram represents ventricular repolarization?
ST segment
What is the primary component of cardiac muscle tissue?
Myocytes
Which cells make the heart vulnerable to injury due to limited proliferative capacity of myocytes?
Cardiac fibroblasts
What are the phases of the ventricular action potential?
Resting, initiation, plateau, and repolarization
Which components are involved in the electrical conduction in the heart?
SA and AV nodes, bundle of His, and Purkinje fibers
What regulates cardiac activity by stimulating cardiac rate and contractility?
Sympathomimetics
What is crucial for excitation-contraction coupling in cardiac myocytes?
Calcium ions and ATP
How is cardiac function measured?
Through electrocardiogram recording and cardiac output
What can affect cardiac output through their effects on the heart, vasculature, and nervous system?
Toxicants
What is the characteristic electrocardiogram sequence?
PR, QRS, ST, and QT intervals
What is the consequence of exposure to sympathomimetics on cardiac rate and contractility?
Increased cardiac rate and contractility
What are the potential disturbances in cardiac function mentioned in the text?
Arrhythmias, ischemic heart disease, and cardiac hypertrophy
Study Notes
Lung Anatomy and Defense Mechanisms
- The lung volume consists mostly of air-filled alveoli, with the lung airways comprising only a small fraction.
- The lung is exposed to high concentrations of reactive oxygen species, both externally and internally.
- The large tidal volume of external air and the branching and narrowing of airways make the lung vulnerable to air contaminants.
- Particle size influences where they are deposited in the respiratory system, affecting their removal mechanisms.
- The air:blood interface in the alveolar wall is crucial for gas exchange, and abnormalities in ventilation:perfusion ratio can lead to lung disease.
- Lung defense mechanisms include aerodynamic filtration, mucociliary escalator, airway reflexes, and pulmonary alveolar macrophages.
- Loss of cilia from the mucociliary escalator can lead to the accumulation of excess mucus and bacterial growth.
- Pulmonary alveolar macrophages play a role in particle clearance and can release harmful enzymes and inflammatory cytokines.
- Pulmonary surfactant, essential for proper lung function, can be underproduced in premature infants or inactivated by acute lung injury.
- Acute respiratory distress syndrome can result from high exposure to corrosive or toxic agents, leading to damage to type-2 cells.
- Lung toxicity can stem from problems in lung functional anatomy, such as the need for specific cellular regeneration and repair after serious damage.
- The lung is particularly susceptible to air contaminants due to its special vulnerabilities, such as the large tidal volume of external air and the branching and narrowing of airways.
Vascular Toxicity and Toxic Responses of the Visual System and Skin
- Atherosclerosis involves vessel wall changes with focal intimal thickenings and plaque formation, leading to ischemia and hypertension
- Major hypotheses for atherosclerosis formation include chemical injury triggering recruitment of platelets and smooth muscle cell migration
- Disturbances of vascular structure and function can result from hypotension, hypertension, and thrombosis caused by toxicant exposure
- Mechanisms of vascular toxicity include alterations in membrane structure and function, redox stress, and vessel-specific bioactivation of protoxicants
- Common vasculotoxic agents include nicotine, cocaine, heavy metals, and 1,3-butadiene, each with specific effects on the cardiovascular system
- All toxicants absorbed into the circulatory system contact vascular cells before reaching other body sites
- Chemically induced disturbances in cardiac function may consist of effects on 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
- Ocular absorption and distribution following topical exposure can affect the cornea, conjunctiva, and eyelids
- Tear film, with both hydrophobic and hydrophilic properties, is the first site of action for toxic chemicals and systemic drugs
- Toxic responses of the visual system and skin can result from environmental and occupational exposure to various toxins
- Direct exposure to chemicals, gases, and particles can affect all parts of the eye, leading to structural and functional alterations
Cardiac Electrophysiology and Function
- Cardiac muscle tissue is primarily composed of myocytes joined by tight gap junctions
- The heart contains various cellular phenotypes including myocytes, cardiac fibroblasts, vascular cells, Purkinje cells, and connective tissue cells
- Limited proliferative capacity of myocytes and promotion of cardiac fibroblast proliferation make the heart vulnerable to injury
- The ventricular action potential consists of four phases: resting, initiation, plateau, and repolarization
- Electrical conduction in the heart involves pacemaker cells (SA and AV nodes), bundle of His, and Purkinje fibers
- The electrical impulse migration allows the atria to fully contract before the ventricles depolarize
- The characteristic electrocardiogram includes PR, QRS, ST, and QT intervals
- Cardiac activity is regulated by the autonomic nervous system, 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
- Cardiac function is measured through electrocardiogram recording and cardiac output, which is dependent on heart rate and stroke volume
- Toxicants can affect cardiac output through their effects on the heart, vasculature, and nervous system
- Disturbances in cardiac function include abnormal heart rhythm (arrhythmias), ischemic heart disease, and cardiac hypertrophy leading to heart failure
Cardiac Electrophysiology and Function
- Cardiac muscle tissue is primarily composed of myocytes joined by tight gap junctions
- The heart contains various cellular phenotypes including myocytes, cardiac fibroblasts, vascular cells, Purkinje cells, and connective tissue cells
- Limited proliferative capacity of myocytes and promotion of cardiac fibroblast proliferation make the heart vulnerable to injury
- The ventricular action potential consists of four phases: resting, initiation, plateau, and repolarization
- Electrical conduction in the heart involves pacemaker cells (SA and AV nodes), bundle of His, and Purkinje fibers
- The electrical impulse migration allows the atria to fully contract before the ventricles depolarize
- The characteristic electrocardiogram includes PR, QRS, ST, and QT intervals
- Cardiac activity is regulated by the autonomic nervous system, 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
- Cardiac function is measured through electrocardiogram recording and cardiac output, which is dependent on heart rate and stroke volume
- Toxicants can affect cardiac output through their effects on the heart, vasculature, and nervous system
- Disturbances in cardiac function include abnormal heart rhythm (arrhythmias), ischemic heart disease, and cardiac hypertrophy leading to heart failure
Test your knowledge of lung anatomy and defense mechanisms with this quiz. Explore the intricacies of the lung's structure, its susceptibility to air contaminants, and the defense mechanisms it employs to protect itself. From the alveoli to pulmonary surfactant, this quiz covers essential aspects of lung function and defense.
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