Guyton and Hall Physiology Chapter 38 - Pulmonary Ventilation
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Questions and Answers

What is the primary role of cilia in the respiratory passages?

  • To produce sound in vocal cords
  • To absorb oxygen from the air
  • To transport particles to the pharynx (correct)
  • To enhance the senses of smell

    • Which structure is directly responsible for creating pitch changes in vocalization?

  • Thyroid cartilage
  • Arytenoid cartilages
  • Cricoid cartilage
  • Vocal ligaments (correct)

    • What is the maximum particle size that can effectively enter the lungs through the nose?

  • 1 micrometer
  • 6 micrometers (correct)
  • 5 micrometers
  • 10 micrometers

    • How do particles between 1 and 5 micrometers typically behave in the respiratory system?

    <p>They settle in the smaller bronchioles</p> Signup and view all the answers

    What is the primary anatomical feature that causes turbulence in the airflow through the nasal passages?

    <p>Turbinates (conchae)</p> Signup and view all the answers

    What role do mast cells play during allergic reactions in the lungs?

    <p>They cause airway obstruction by releasing substances.</p> Signup and view all the answers

    What structures are primarily responsible for secreting mucus in the respiratory passages?

    <p>Goblet cells and submucosal glands.</p> Signup and view all the answers

    Where does the greatest resistance to airflow occur in the bronchial tree?

    <p>In some of the larger bronchioles and bronchi near the trachea.</p> Signup and view all the answers

    Which irritants can lead to obstructive constriction of the airways?

    <p>Smoke, dust, sulfur dioxide, and acidic elements in smog.</p> Signup and view all the answers

    Which part of the respiratory system is primarily composed of smooth muscle?

    <p>Respiratory bronchioles.</p> Signup and view all the answers

    What contributes to keeping the respiratory passages moist?

    <p>A layer of mucus that coats the entire surface.</p> Signup and view all the answers

    What effect do allergic reactions have on the bronchial smooth muscle?

    <p>They cause excessive contraction of the smooth muscle.</p> Signup and view all the answers

    How much pressure is typically sufficient to cause airflow for quiet breathing?

    <p>Less than 1 cm H2O pressure gradient.</p> Signup and view all the answers

    What is a potential consequence of excessive contraction of the smooth muscle in the bronchi?

    <p>Increased airway obstruction.</p> Signup and view all the answers

    What substance is primarily responsible for the allergic asthma reaction?

    <p>Slow reactive substance of anaphylaxis.</p> Signup and view all the answers

    What are the three distinct normal respiratory functions performed by the nasal cavities?

    <p>Warming, humidification, and filtration of air</p> Signup and view all the answers

    What is the primary role of the larynx in the process of phonation?

    <p>To act as a vibrator</p> Signup and view all the answers

    How is the pitch of the vibration of the vocal cords primarily determined?

    <p>By the degree of stretch of the cords</p> Signup and view all the answers

    What is the filtration function of the nose primarily achieved through?

    <p>Hairs at the entrance of the nostrils and turbulent precipitation</p> Signup and view all the answers

    What temperature is the inspired air typically warmed to before reaching the trachea?

    <p>Within 1°F of body temperature</p> Signup and view all the answers

    What happens to the vocal cords during normal breathing?

    <p>They are wide open for airflow</p> Signup and view all the answers

    What could potentially happen if a person breathes air directly into the trachea through a tracheostomy?

    <p>Serious lung crusting and infection</p> Signup and view all the answers

    What is the area of the nasal cavities that contributes to their air-conditioning function?

    <p>Approximately 160 square centimeters</p> Signup and view all the answers

    What is the primary role of alveolar macrophages in the respiratory system?

    <p>To remove entrapped particles in the alveoli</p> Signup and view all the answers

    What initiates the sneeze reflex?

    <p>Irritation in the nasal passageways</p> Signup and view all the answers

    Which of the following structures plays a key role in vocalization?

    <p>The uvula</p> Signup and view all the answers

    What is a consequence of having an excess of particles in the alveoli?

    <p>Growth of fibrous tissue in the alveolar septa</p> Signup and view all the answers

    How do most particles in cigarette smoke affect the lungs?

    <p>They mostly remain suspended and expelled in expired air</p> Signup and view all the answers

    Which cranial nerve transmits afferent impulses for the sneeze reflex?

    <p>Trigeminal nerve (V)</p> Signup and view all the answers

    What additional structures are involved in speech besides the respiratory system?

    <p>Cerebral cortex and resonance structures</p> Signup and view all the answers

    Which is NOT a function of the nasal passages related to respiration?

    <p>Producing vocal sounds</p> Signup and view all the answers

    What happens to the air during the sneeze reflex?

    <p>It is expelled rapidly through the nose</p> Signup and view all the answers

    What role do lymphatics play in respiratory function?

    <p>They carry away particles trapped in alveoli</p> Signup and view all the answers

    What is the primary function of the ciliated epithelium in the respiratory passages?

    <p>To trap and remove particles from inspired air</p> Signup and view all the answers

    How does sympathetic stimulation affect the bronchioles?

    <p>It leads to the dilation of the bronchioles</p> Signup and view all the answers

    What role do alveolar macrophages play in the respiratory system?

    <p>They help in phagocytosing foreign particles</p> Signup and view all the answers

    What initiates the cough reflex in the bronchi and trachea?

    <p>Irritation from foreign matter or touch</p> Signup and view all the answers

    Which statement about the filtration function of the nose is true?

    <p>It primarily relies on ciliated epithelium for trapping particles</p> Signup and view all the answers

    What effect does muscle contraction in the smaller bronchioles have?

    <p>It causes occlusion of the bronchioles</p> Signup and view all the answers

    Which of the following hormones primarily facilitates bronchiole dilation?

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

    What is the rate at which cilia in the respiratory passages beat?

    <p>10 to 20 times per second</p> Signup and view all the answers

    What is the consequence of mucus collecting in the lumens of bronchioles?

    <p>Increased airflow resistance</p> Signup and view all the answers

    What is one primary function of the nasal passages during respiration?

    <p>Humidifying and warming inhaled air</p> Signup and view all the answers

    What happens to alveolar pressure when the radius of the alveolus is halved?

    <p>It doubles</p> Signup and view all the answers

    Which type of work is NOT performed by respiratory muscles during expiration?

    <p>No work is performed</p> Signup and view all the answers

    What is the primary role of surfactant in the alveoli?

    <p>To reduce surface tension</p> Signup and view all the answers

    How does surface tension relate to alveolar radius?

    <p>It is inversely related</p> Signup and view all the answers

    What is the pressure in an alveolus lined with pure water compared to one with surfactant?

    <p>About four times greater</p> Signup and view all the answers

    What is the total lung capacity for an average adult male as given in the table?

    <p>5800 ml</p> Signup and view all the answers

    Which of the following lung volumes is associated with the amount of air that can be inhaled after a normal exhalation?

    <p>Inspiratory capacity</p> Signup and view all the answers

    What is the average residual volume for an average adult male as per the provided data?

    <p>1200 ml</p> Signup and view all the answers

    Which pulmonary volume represents the maximum amount of air that can be exhaled after a maximum inhalation?

    <p>Vital capacity</p> Signup and view all the answers

    What primarily influences the variation in lung volumes among healthy adults?

    <p>Physical fitness and age</p> Signup and view all the answers

    What primarily composes the walls of the bronchioles?

    <p>Smooth muscle</p> Signup and view all the answers

    Which irritants can trigger airway obstruction in obstructive lung diseases?

    <p>Smoke and dust</p> Signup and view all the answers

    How is the mucus in the respiratory passages maintained?

    <p>Secreted by goblet cells and submucosal glands</p> Signup and view all the answers

    What is the role of the slow reactive substance of anaphylaxis in asthma?

    <p>Triggers airway obstruction</p> Signup and view all the answers

    What is the typical pressure gradient needed for quiet breathing?

    <p>1 cm H2O</p> Signup and view all the answers

    Where does the greatest resistance to airflow occur in the bronchial tree?

    <p>In some larger bronchioles</p> Signup and view all the answers

    What is a direct effect of excessive contraction of smooth muscle in the bronchi?

    <p>Increased airway resistance</p> Signup and view all the answers

    What types of tissues primarily make up the respiratory bronchiole?

    <p>Pulmonary epithelium and fibrous tissue</p> Signup and view all the answers

    What process maintains the clearance of respiratory passageways?

    <p>Cilia movement</p> Signup and view all the answers

    What is a common result of local, non-nervous reactions in the lungs?

    <p>Obstructive constriction of airways</p> Signup and view all the answers

    The total compliance of both lungs together in a normal adult averages about 250 ml of air/cm H2O transpulmonary pressure.

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

    When the lungs are filled with saline solution, the surface tension effect is present due to the air-fluid interface.

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

    The transpulmonary pressures required to expand air-filled lungs are greater than those required to expand lungs filled with saline solution.

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

    Tissue elastic forces in the air-filled lung represent approximately two-thirds of the total lung elasticity.

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

    The compliance of the lungs is defined as the extent to which lung volume changes for each unit increase in transpulmonary pressure.

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

    Surfactant is secreted by type I alveolar epithelial cells.

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

    Dipalmitoyl phosphatidylcholine is a significant component of surfactant that reduces surface tension.

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

    Strong measures for treating respiratory issues are rarely needed.

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

    The thoracic cage does not require muscular effort to expand if the lungs were absent.

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

    Surfactant acts as a surface-active agent by increasing the surface tension of water.

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

    A typical basic spirometer consists of a drum inverted over a chamber of oil.

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

    The average total lung capacity for adult males according to the data provided is 5800 ml.

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

    Residual volume is typically measured at 1100 ml for healthy adult males.

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

    Functional residual capacity is the sum of residual volume and expiratory reserve volume.

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

    Inspiratory capacity for an average adult male is 2400 ml.

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

    The lung volumes can vary significantly based on factors such as altitude and physical fitness.

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

    Vital capacity represents the maximum amount of air the lungs can hold after maximum inhalation.

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

    The average functional residual capacity for an average adult male is 2300 ml.

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

    The average lung capacity for women is always higher than that for men.

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

    The average inspiratory capacity for women is significantly lower than that of men.

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

    Match the following muscles with their role in pulmonary ventilation:

    <p>Diaphragm = Primary muscle for inspiration Internal intercostals = Muscles that assist in expiration Abdominal recti = Muscles that pull lower ribs downward External intercostals = Muscles that assist in inspiration</p> Signup and view all the answers

    Match the following actions with their corresponding respiratory phase:

    <p>Inspiration = Lowering of diaphragm Expiration = Relaxation of diaphragm Heavy breathing = Contraction of abdominal muscles Normal quiet breathing = Mainly diaphragm movement</p> Signup and view all the answers

    Match the following terms with their definitions related to lung mechanics:

    <p>Elastic recoil = The tendency of lungs to return to original size Anteroposterior diameter = Dimension increased during rib elevation Chest cavity = Space that houses the lungs and heart Lung expansion = Increase in lung volume during inspiration</p> Signup and view all the answers

    Match the following lung structures with their functions:

    <p>Diaphragm = Contracts to create negative pressure for inhalation Intercostal muscles = Facilitate movement of ribs Abdominal muscles = Assist in expelling air from lungs Elastic structures = Aid in lung compression during expiration</p> Signup and view all the answers

    Match the following phases of breathing with their primary characteristics:

    <p>Inspiration = Involves active muscle contraction Expiration = Can occur passively through elastic recoil Normal breathing = Primarily diaphragm action Heavy breathing = Involves additional muscle engagement</p> Signup and view all the answers

    Match the following terms related to alveoli with their definitions:

    <p>Compliance work = Work required to expand the lungs against elastic forces Tissue resistance work = Work required to overcome the viscosity of lung structures Airway resistance work = Work required to overcome resistance to airflow into the lungs Surfactant = Substance that reduces alveolar surface tension</p> Signup and view all the answers

    Match the following conditions with their corresponding pressures:

    <p>Average-sized alveolus with surfactant = 4 cm H2O pressure Average-sized alveolus without surfactant = 18 cm H2O pressure Radius halved alveolus = Increased alveolar pressure Normal breathing expiration = Passive process</p> Signup and view all the answers

    Match the following alveolar properties with their effects:

    <p>Smaller alveolus = Greater alveolar pressure due to surface tension Normal surfactant = Decreases effort required by respiratory muscles Pure water lining = Increases required pressure significantly Passive expiration = No muscular effort needed</p> Signup and view all the answers

    Match the following types of work with their descriptions in the breathing process:

    <p>Compliance work = Against elastic forces of lungs Tissue resistance work = Overcome viscosity in lung structures Airway resistance work = Overcome resistance to airflow Inspiratory work = Active work done by respiratory muscles</p> Signup and view all the answers

    Match the following measurements with their associated alveolar conditions:

    <p>100 micrometers radius = 4 cm H2O pressure with surfactant 50 micrometers radius = Doubled alveolar pressure Normal surfactant = Reduces pressure significantly No surfactant = Higher pressure of 18 cm H2O</p> Signup and view all the answers

    Study Notes

    Respiratory Functions of the Nose

    • The nose warms, humidifies, and filters air.
    • The nasal cavity has a surface area of about 160 square centimeters.
    • Air is warmed to within 1°F of body temperature and 2% to 3% of full saturation with water vapor before reaching the trachea.
    • Large particles are filtered by nasal hairs.
    • Turbulent precipitation removes smaller particles.

    Filtration Function of The Nose

    • Air passing through the nose hits obstructions like conchae, septum, and pharyngeal wall.
    • Suspended particles in the air have more mass and momentum than air and therefore hit the obstructions, become entrapped in mucus, and are transported by cilia to the pharynx to be swallowed.
    • Particles larger than 6 micrometers in diameter are rarely found in the lungs.
    • Particles between 1 and 5 micrometers settle in smaller bronchioles due to gravitational precipitation.
    • Particles less than 0.3 micrometers are not efficiently removed by the nose.

    Sneeze Reflex

    • The sneeze reflex is similar to the cough reflex.
    • It is initiated by irritation in the nasal passageways.
    • Afferent impulses pass in the 5th cranial nerve to the medulla.
    • The uvula is depressed, causing a large amount of air to pass rapidly through the nose.

    Resistance to Airflow in the Bronchial Tree

    • Airflow resistance is greatest in some of the larger bronchioles and bronchi near the trachea.
    • The smallest bronchioles have a large combined resistance, even though individual resistance is low.
    • Bronchiolar resistance can increase due to muscle contraction, edema, or mucus collection.

    Nervous and Local Control of Bronchiolar Musculature

    • Sympathetic nerve fiber control of bronchioles is weak.
    • Bronchial tree is exposed to norepinephrine and epinephrine released by sympathetic stimulation of the adrenal medulla.
    • Epinephrine causes bronchodilation.

    Cough Reflex

    • The cough reflex is triggered by irritation in the trachea and bronchi.
    • It is similar to the sneeze reflex.

    Mucus Lining the Respiratory Passageways

    • The respiratory passages from the nose to the terminal bronchioles are coated with mucus.
    • Mucus is secreted by goblet cells and submucosal glands.
    • Mucus keeps surfaces moist and traps small particles.
    • Cilia beat continually to move mucus towards the pharynx.

    Vocalization

    • Speech involves respiration, speech nervous control centers in the cerebral cortex, respiratory control centers of the brain, and articulation and resonance of mouth and nasal cavities.

    Phonation

    • The larynx acts as a vibrator.
    • Vocal folds (vocal cords) protrude from the lateral walls of the larynx.
    • During normal breathing, vocal cords are open for easy passage of air.
    • During phonation, vocal cords move together, causing air passage to vibrate.

    Pitch of Vibrations

    • The pitch of vocal cord vibrations is determined by the degree of stretch of the cords, how tightly they are approximated, and their mass.
    • Vocal cords are stretched by forward rotation of the thyroid cartilage or posterior rotation of the arytenoid cartilages.
    • The thyroarytenoid muscles can loosen the vocal cords.

    Surface Tension in Alveoli

    • Surfactant's Importance: Surfactant reduces surface tension in the alveoli, decreasing the pressure needed for the respiratory muscles to expand the lungs.
    • Alveoli Radius & Pressure: Smaller alveoli have higher pressure due to surface tension. Alveoli with half the radius have double the pressure.
    • Premature Infants: Small premature infants, with smaller alveoli, are highly susceptible to this phenomenon.

    Work of Breathing

    • Inspiration: The respiratory muscles perform "work" during inspiration, not expiration, due to passive elastic recoil of the lungs and chest cage during expiration.
    • Work Components: Inspiration involves three types of "work": compliance work (against lung/chest elasticity), tissue resistance work (viscosity), and airway resistance work (airflow obstruction).

    Lung Volumes and Capacities

    • Spironmeter: A device used to measure lung volume with a gas chamber and a counterbalanced drum.
    • Lung Volumes: Four volumes measured: tidal volume (normal inhalation), expiratory reserve (forced expiration), inspiratory reserve (forced inhalation), and residual volume (air remaining after maximum exhalation).
    • Lung Capacities: The sum of several lung volumes, including vital capacity (maximum air exhaled after a deep inspiration), inspiratory capacity (maximum air inhaled from resting exhalation), and functional residual capacity (air remaining after normal exhalation).

    Airway Obstruction

    • Smooth Muscle Control: Bronchi and bronchioles contain smooth muscle that can narrow the airways, contributing to obstructive lung diseases.
    • Irritants: Smoke, dust, sulfur dioxide, and acidic elements in smog can constrict airways through both parasympathetic nervous reflexes and direct tissue-level responses.

    Mucus and Cilia Action

    • Mucous Lining: Respiratory passages are lined with mucus secreted by goblet cells and submucosal glands, keeping the passages moist.
    • Cilia: The cilia move the mucus and entrapped particles upward, towards the pharynx, to be swallowed, clearing the airways from dust and debris.

    Speech Mechanisms

    • Phonation: The process of producing sound using the larynx.
    • Vocal Folds: Vibrate to create sound waves, controlled by the larynx muscles.
    • Pitch: Controlled by the tension and mass of the vocal folds.
    • Articulation: The shaping of the sound into words, articulated by the structures of the mouth.

    Lung Compliance

    • Lung compliance is the change in lung volume for each unit change in transpulmonary pressure.
    • Transpulmonary pressure is the difference between alveolar pressure and pleural pressure.
    • Normal adult lung compliance is 200 ml of air/cm H2O transpulmonary pressure.
    • This means for every 1 cm H2O increase in transpulmonary pressure, lung volume increases by 200 ml after 10-20 seconds.

    Lung Expansion

    • It takes 3 times more transpleural pressure to expand air filled lungs compared to saline-filled lungs.
    • This difference is because of surface tension forces in alveoli.
    • Tissue elastic forces contribute to the elastic recoil of the lungs.
    • Fluid-air surface tension in alveoli accounts for ⅔ of the elastic force.
    • Tissue elasticity only accounts for ⅓ of the elastic force.

    Surfactant

    • Surfactant is a surface-active agent secreted by type II alveolar epithelial cells that reduces the surface tension of water.
    • This reduces the collapsing force of alveoli and ensures proper gas exchange.
    • Surfactant is composed of phospholipids, proteins, and ions.
    • Dipalmitoyl phosphatidylcholine is the main component that reduces surface tension.

    Pulmonary Volumes and Capacities

    • Residual volume is the volume of air remaining in the lungs after forceful expiration.
    • This volume averages 1200 ml.
    • Inspiratory capacity is the amount of air a person can inhale, beginning at normal expiratory level.
    • It includes the tidal volume and inspiratory reserve volume.
    • This capacity is typically 3500 ml.
    • Functional residual capacity is the volume of air remaining in the lungs after normal expiration.
    • It includes the expiratory reserve volume and the residual volume.

    Respiratory Particle Removal

    • Nasal turbulence effectively removes particles greater than 6 micrometers in diameter.
    • This is smaller than a red blood cell.
    • Particles between 1-5 micrometers settle in the smaller bronchioles due to gravity.
    • Smaller particles may enter the alveoli where they are phagocytized or cleared by other mechanisms.

    Mechanics of Pulmonary Ventilation

    • Pulmonary ventilation is the process of moving air into and out of the lungs, primarily through the actions of the diaphragm and intercostal muscles.

    • Inspiration is driven by the contraction of the diaphragm, pulling it downward and expanding the chest cavity. This creates negative pressure in the lungs, drawing air in.

    • Quiet expiration is passive, relying on the elastic recoil of the lungs, chest wall, and abdominal structures to push air out.

    • During forceful expiration, abdominal muscles and internal intercostals contract.

    Muscles Involved in Pulmonary Ventilation

    • Diaphragm: The primary muscle for inspiration, contracting to pull the lungs downward.
    • External intercostals: Elevate the rib cage during inspiration.
    • Internal intercostals: Depress the rib cage during forced expiration.
    • Abdominal muscles: Contribute to forced expiration by compressing the abdominal contents upward against the diaphragm.

    Pressures Involved in Pulmonary Ventilation

    • Alveolar pressure: The internal pressure inside the alveoli.
    • Pleural pressure: The pressure in the thin space between the lung and the chest wall.
    • Surface tension: Refers to the force within the alveoli that tends to hold the alveoli closed.
    • Surfactant: A substance produced by the lungs that reduces surface tension, preventing alveoli from collapsing.

    Work of Breathing

    • Inspiration requires active muscle contraction, while expiration is typically passive, except during forceful breathing.
    • The work of inspiration can be divided into three components:
      • Compliance work: Expanding the lungs against their elastic forces.
      • Tissue resistance work: Overcoming the viscosity of lung and chest wall structures.
      • Airway resistance work: Overcoming airway resistance to airflow.

    Pulmonary Volumes and Capacities

    • Tidal volume (VT): Volume of air breathed in and out during normal quiet breathing.
    • Functional residual capacity (FRC): Volume of air remaining in the lungs at the end of a normal expiration.
    • Expiratory reserve volume (ERV): The additional volume of air that can be forcefully exhaled after a normal expiration.
    • Residual volume (RV): The volume of air that remains in the lungs even after a maximum exhalation.
    • Inspiratory capacity (IC): The maximum volume of air that can be inhaled after a normal expiration.
    • Inspiratory reserve volume (IRV): The additional volume of air that can be forcefully inhaled after a normal inspiration.
    • Vital capacity (VC): The maximum volume of air that can be exhaled following a maximum inhalation.
    • Total lung capacity (TLC): The total volume of air that the lungs can hold after a maximum inhalation.

    Speech

    • Consists of two main components:
      • Phonation: Production of sound waves at the larynx, primarily through the vibration of vocal cords.
      • Articulation: Modification of sound waves by the structures of the mouth, shaping them into recognizable speech.

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    Description

    This quiz explores the essential functions of the nose in the respiratory system, including its role in warming, humidifying, and filtering air. It also delves into the filtration mechanisms and the sneeze reflex that helps in clearing unwanted particles. Test your knowledge on how the nose protects the lungs and facilitates breathing.

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