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Questions and Answers
What is the primary role of ribs 11 and 12 during respiration?
What is the primary role of ribs 11 and 12 during respiration?
- They are responsible for upward movement of the sternum.
- They contribute to a major change in lung volume.
- They participate in a minor change to the chest contour. (correct)
- They primarily assist in deep inhalation.
What is the function of the intrapleural space?
What is the function of the intrapleural space?
- It directly facilitates the movement of air in and out of the lungs.
- It houses the serous membrane.
- It contains lung tissue.
- It holds intrapleural fluid and maintains negative pressure. (correct)
What is true about the pleurae in relation to the lungs?
What is true about the pleurae in relation to the lungs?
- The parietal pleura directly covers the surface of the lung.
- The visceral pleura is the outer layer of the lung. (correct)
- The pleurae are composed of muscle tissue.
- The visceral pleura lines the thoracic cavity.
What happens to the thoracic diameter during the backward movement of the lower sternum?
What happens to the thoracic diameter during the backward movement of the lower sternum?
Which statement accurately describes the 'caliper' motion of the ribs?
Which statement accurately describes the 'caliper' motion of the ribs?
What is a key feature of the right lung compared to the left lung?
What is a key feature of the right lung compared to the left lung?
Which fissures are found in the right lung?
Which fissures are found in the right lung?
What anatomical structure is located in the mediastinum?
What anatomical structure is located in the mediastinum?
What name is given to the part of the lung where the mainstem bronchi enter?
What name is given to the part of the lung where the mainstem bronchi enter?
Why is the left lung smaller than the right lung?
Why is the left lung smaller than the right lung?
What is the relationship between alveolar radius and internal pressure according to Laplace's Law?
What is the relationship between alveolar radius and internal pressure according to Laplace's Law?
How does surfactant affect surface tension (ST) in the alveoli?
How does surfactant affect surface tension (ST) in the alveoli?
What happens to surface tension (ST) during exhalation?
What happens to surface tension (ST) during exhalation?
What is the formula represented by Laplace’s Law?
What is the formula represented by Laplace’s Law?
Which statement accurately describes airway resistance (RAW)?
Which statement accurately describes airway resistance (RAW)?
What is the primary muscle of inspiration?
What is the primary muscle of inspiration?
What does elastance measure in the context of lung mechanics?
What does elastance measure in the context of lung mechanics?
What defines compliance in lung mechanics?
What defines compliance in lung mechanics?
What does a more negative intra-thoracic pressure indicate?
What does a more negative intra-thoracic pressure indicate?
Which factor does NOT influence lung/chest wall elasticity?
Which factor does NOT influence lung/chest wall elasticity?
What is the formula used to calculate compliance?
What is the formula used to calculate compliance?
Which of the following best describes the thoracic cavity?
Which of the following best describes the thoracic cavity?
How is elastance calculated in the context of lung mechanics?
How is elastance calculated in the context of lung mechanics?
What happens to the driving pressure if the viscosity of a fluid increases, according to Poiseuille's Law?
What happens to the driving pressure if the viscosity of a fluid increases, according to Poiseuille's Law?
Which factor contributes to increased airway resistance (RAW)?
Which factor contributes to increased airway resistance (RAW)?
How is conductance (G) related to resistance (R) in the respiratory system?
How is conductance (G) related to resistance (R) in the respiratory system?
Which type of gas flow is characterized by orderly, parallel layers of fluid?
Which type of gas flow is characterized by orderly, parallel layers of fluid?
What does Reynolds' number (RN) indicate in terms of gas flow?
What does Reynolds' number (RN) indicate in terms of gas flow?
What is the relationship between the radius of a tube and the resistance according to the equation R = 8nl / πr^4?
What is the relationship between the radius of a tube and the resistance according to the equation R = 8nl / πr^4?
Which of the following variables are inversely related to flow (GAW)?
Which of the following variables are inversely related to flow (GAW)?
What effect does branching of the airways have on airway resistance (RAW)?
What effect does branching of the airways have on airway resistance (RAW)?
Study Notes
Rib Movement
- Ribs 11-12 are termed "floating" ribs and contribute minimally to chest contour changes.
- These ribs are moved in a "caliper" motion, involving upward and outward movement.
Pleurae
- Comprises a serous membrane lining the lungs and thorax, with two layers:
- Visceral pleura (inner lining covering lung surfaces)
- Parietal pleura (outer layer lining the thoracic cavity)
- The intrapleural space contains intrapleural fluid and has negative pressure.
Gross Anatomy of the Lungs
- Right lung is larger and shorter (due to the liver), has three lobes and two fissures (horizontal and oblique).
- Left lung is smaller (due to the heart's apex), has two lobes, one oblique fissure, and a lingula that represents the middle lobe.
Thoracic Cavity
- Contains the mediastinum, which holds the heart, trachea, major blood vessels, and nerves.
- The hilum is where the mainstem bronchi enter the lungs.
- Consists of two pleural cavities and has a negative intra-thoracic (pleural) pressure compared to atmospheric pressure.
Diaphragm
- Dome-shaped muscle dividing the thoracic and abdominal cavities.
- Serves as the primary muscle for inspiration, innervated by the phrenic nerve.
Lung Mechanics
- Elastance (E): The lung's ability to return to original shape after distortion, calculated as ΔP/ΔV.
- Compliance (C): The ease of lung distension, calculated as ΔV/ΔP; inversely related to elastance.
Lung/Chest Wall Elasticity
- Composed of tissues beneath the diaphragm, ligaments, cartilages, elastic fibers, and surfactant.
- Surfactant decreases surface tension (ST) and pressure, thereby increasing compliance.
Surface Tension (ST)
- Results from forces at liquid-gas interfaces, promoting alveolar collapse during exhalation.
- Laplace’s Law shows that pressure increases with smaller alveoli (P = 2(ST)/r).
Airway Resistance (RAW)
- Represents the force needed to maintain airflow in the respiratory system, calculated as ΔP/flow.
- Increased RAW factors include decreased airway diameter and directional changes in airways.
Gas Flows and Airway Resistance
- Poiseuille’s Law describes that driving pressure increases with fluid viscosity, tube length, or flow, particularly when tube radius decreases (R = 8nl/πr^4).
- Conductance (G) relates to airflow capabilities and is inversely related to resistance: GAW = Flow/ΔP.
Types of Gas Flows
- Different patterns exist:
- Laminar Flow: smooth and orderly.
- Turbulent Flow: chaotic and irregular.
- Transitional Flow: a mix of laminar and turbulent flow.
- Reynold’s number (RN) indicates the flow type, determining whether it is laminar or turbulent.
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Description
This quiz explores the mechanics of breathing, focusing on the backward movement of the lower sternum during inhalation. It examines how these actions lead to changes in thoracic dimensions. Gain insights into the physiological processes involved in quiet breathing.
