Respiratory System: Mechanics and Structures
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Respiratory System: Mechanics and Structures

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Questions and Answers

What structures are included in the lower respiratory system?

  • Pulmonary capillaries, bronchial tree, and visceral pleura
  • Diaphragm, external intercostal muscles, and heart
  • Larynx, trachea, bronchi, and lungs (correct)
  • Mouth, nasal cavity, pharynx, and alveoli

    • Which type of cells are primarily involved in the gas exchange within the respiratory membrane?

  • Type I and Type II alveolar cells (correct)
  • Goblet cells and ciliated epithelial cells
  • Mucous cells and bronchial epithelial cells
  • Ciliated pseudostratified cells and alveolar macrophages

    • During inspiration, which muscles contract to aid in the breathing process?

  • Sternocleidomastoid and scalene muscles only
  • Internal intercostal muscles and abdominal muscles
  • Pectoralis major and latissimus dorsi muscles
  • Diaphragm and external intercostal muscles (correct)

    • What is Boyle’s Law primarily associated with in relation to breathing?

    <p>The inverse relationship between pressure and volume</p> Signup and view all the answers

    What is the role of surfactant in the lungs?

    <p>To decrease surface tension and prevent alveolar collapse</p> Signup and view all the answers

    Which of the following options describes the factors that influence pulmonary ventilation?

    <p>Airway resistance, alveolar surface tension, and lung compliance</p> Signup and view all the answers

    What does the term 'dead space' refer to in pulmonary physiology?

    <p>Areas of the lung that do not participate in gas exchange</p> Signup and view all the answers

    Which of the following statements accurately describes the pulmonary circulation?

    <p>It consists of the pulmonary arteries and veins.</p> Signup and view all the answers

    What role do the intercostal muscles play during inspiration at rest?

    <p>They help to expand the rib cage.</p> Signup and view all the answers

    What happens to atmospheric pressure during the process of inspiration?

    <p>It decreases as air flows in.</p> Signup and view all the answers

    Which muscles are primarily involved in heavy breathing during inspiration?

    <p>Sternocleidomastoid, levator scapulae, and scalenes.</p> Signup and view all the answers

    What function do the abdominal muscles serve during heavy expiration?

    <p>They push the diaphragm superiorly.</p> Signup and view all the answers

    What triggers inhalation at rest?

    <p>Contraction of intercostal muscles and diaphragm.</p> Signup and view all the answers

    During inspiration, what occurs to the pressure in the thoracic cavity?

    <p>It decreases below atmospheric pressure.</p> Signup and view all the answers

    Which of the following is NOT involved in the process of normal expiration at rest?

    <p>Sternocleidomastoid.</p> Signup and view all the answers

    What is the primary goal of the respiratory muscles during inspiration?

    <p>To increase thoracic cavity volume.</p> Signup and view all the answers

    How does the size of a sphere affect surface tension according to LaPlace’s Law?

    <p>Smaller spheres have higher surface tension.</p> Signup and view all the answers

    What happens to air movement between a small sphere and a larger sphere based on surface tension?

    <p>Air moves from the small sphere to the large sphere.</p> Signup and view all the answers

    What effect does surfactant have on the surface tension in smaller and larger spheres?

    <p>It decreases surface tension more significantly in smaller spheres.</p> Signup and view all the answers

    What clinical condition is associated with insufficient surfactant in infants?

    <p>Infant respiratory distress syndrome (IRDS)</p> Signup and view all the answers

    What is meant by the term 'lung compliance'?

    <p>The extent to which lung volume changes with changes in transpulmonary pressure.</p> Signup and view all the answers

    What is indicated by a healthy lung tissue's compliance?

    <p>It is easily stretched and distensible.</p> Signup and view all the answers

    In the context of surface tension and spheres, what happens to the pressures of small and large spheres when surfactant is present?

    <p>They stabilize to similar pressures.</p> Signup and view all the answers

    How does a change in transpulmonary pressure (ΔP) affect lung volume (ΔV)?

    <p>Lung volume changes are directly proportional to transpulmonary pressure changes.</p> Signup and view all the answers

    What is the primary cause of bronchoconstriction during an asthma attack?

    <p>Irritants or allergens</p> Signup and view all the answers

    Which medication is primarily used to prevent airway inflammation in asthma patients?

    <p>Corticosteroids</p> Signup and view all the answers

    According to Boyle’s Law, what happens to pressure when volume decreases?

    <p>Pressure increases</p> Signup and view all the answers

    What is one of the primary physiological characteristics of asthma?

    <p>Oedema in the walls of small airways</p> Signup and view all the answers

    What does compliance measure in the context of the respiratory system?

    <p>Lung expansion ability</p> Signup and view all the answers

    What does compliance (C) measure in the lungs?

    <p>The change in lung volume per change in intrapulmonary pressure</p> Signup and view all the answers

    What condition is characterized by decreased lung compliance requiring greater pressure to inflate the lungs?

    <p>Pulmonary fibrosis</p> Signup and view all the answers

    Which condition leads to increased lung compliance and is known to be obstructive in nature?

    <p>Emphysema</p> Signup and view all the answers

    What is the approximate anatomical dead space in the respiratory system?

    <p>150 mL</p> Signup and view all the answers

    Why is the total dead space significant in respiratory physiology?

    <p>It indicates the effectiveness of gas exchange.</p> Signup and view all the answers

    What is the fundamental difference between capacities and volumes in respiratory physiology?

    <p>Volumes can exist independently; capacities always involve two or more volumes.</p> Signup and view all the answers

    What happens to the lung pressure required for inspiration in conditions of increased lung compliance?

    <p>It decreases.</p> Signup and view all the answers

    What is a common clinical condition that reflects decreased lung compliance due to insufficient surfactant?

    <p>Infant respiratory distress syndrome (IRDS)</p> Signup and view all the answers

    Study Notes

    Respiratory System: Lower Respiratory System

    • Lower respiratory system: larynx, trachea, bronchi, and lungs
    • Conducting zone structures (respiratory passageways), and respiratory zone structures (gas exchange)
    • Larynx: cricoid, thyroid cartilage, vocal cords
    • Trachea: mucosa (ciliated pseudostratified epithelium), goblet cells (mucous)
    • Respiratory membrane: Type I and Type II alveolar cells, basement membrane, pulmonary capillaries
    • Blood supply to lungs: Pulmonary and bronchial circulations

    Mechanics of Breathing: Introduction

    • At rest, inspiration is an active process due to the contraction of the diaphragm, which flattens it downwards.
    • External intercostal muscle contraction pulls the rib cage up and out.
    • Expiration at rest is a passive process.

    Mechanics of Breathing: Inspiration & Expiration

    • During inspiration, the intrapulmonary pressure becomes lower than atmospheric pressure, allowing air to flow into the lungs.
    • When inspiration is forceful during exercise, additional muscles are used, including the sternocleidomastoid, levator scapulae, and scalenes.
    • Expiration, when forceful during exercise, relies on abdominal muscles that contract to push the diaphragm superiorly.

    Surface Tension

    • LaPlace's Law states that the pressure generated in a sphere is inversely proportional to its radius.
    • In smaller spheres, surface tension is higher, leading to a higher pressure compared to larger spheres.
    • Surfactant reduces surface tension more effectively in smaller spheres than in larger spheres, stabilizing pressure.

    Lung Compliance

    • Healthy lung tissue is compliant, meaning it is easily stretched and distensible.
    • Lung compliance, represented by C, is determined by the distensibility of lung tissue and alveolar surface tension.
    • In pulmonary fibrosis, excessive connective tissue in the alveolar walls decreases lung compliance.
    • Infant respiratory distress syndrome (IRDS) results from a lack of surfactant, reducing lung compliance.
    • Emphysema, an obstructive disease characterized by large, floppy alveoli, increases lung compliance.

    Lung Volumes and Capacities

    • Tidal volume: volume of air breathed in or out of the lungs during a normal breath at rest.
    • Inspiratory reserve volume (IRV): amount of air that can be forcibly inhaled after a normal tidal volume.
    • Expiratory reserve volume (ERV): amount of air that can be forcibly exhaled after a normal tidal volume.
    • Residual volume: the amount of air remaining in the lungs after a maximal exhalation. This volume cannot be measured by spirometry.
    • Anatomical dead space: volume of air trapped in the respiratory passageways (approximately 150 mL).
    • Alveolar dead space: volume of air trapped in collapsed or obstructed alveoli.

    Clinical Considerations: Chronic Bronchitis and Emphysema

    • Chronic bronchitis features chronically inflamed airways due to abnormal immune responses.
    • This inflammation causes edema in the walls of small airways, excess mucus production, and decreased airway diameter, increasing resistance to airflow.
    • Emphysema is characterized by the destruction of alveolar walls, leading to large, floppy alveoli with decreased elasticity.
    • Asthma is marked by bronchoconstriction triggered by irritants or allergens, leading to an asthma attack.
    • Corticosteroids reduce inflammation, while bronchodilators relax smooth muscle in the bronchioles, alleviating asthma symptoms.

    Boyle's Law

    • Boyle's Law establishes the relationship between pressure and volume: as volume decreases, pressure increases, and vice versa.

    Pressure Changes

    • Transpulmonary pressure (C): the difference between intrapulmonary pressure and intrapleural pressure.
    • Intrapulmonary pressure (E): pressure inside the lungs.
    • Intrapleural pressure (D): pressure within the pleural cavity, which is always negative.
    • Atmospheric pressure (Patm): pressure of the air surrounding the body.

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    Description

    Explore the intricacies of the lower respiratory system, including its anatomy and the mechanics of breathing. This quiz covers structures such as the larynx, trachea, and lungs, as well as the processes of inspiration and expiration. Dive into how these systems work together to facilitate gas exchange.

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