Introduction to the Respiratory System
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Questions and Answers

What structure begins where a terminal bronchiole gives rise to respiratory bronchioles?

  • Conducting zone
  • Respiratory zone (correct)
  • Alveolar sac
  • Alveolar duct

What is the primary function of type II alveolar cells?

  • Formation of the alveolar wall
  • Secretion of pulmonary surfactant (correct)
  • Gas exchange
  • Phagocytosis of pathogens

How are alveoli connected to their neighbors?

  • Bronchioles
  • Alveolar ducts
  • Capillaries
  • Alveolar pores (correct)

What type of cell constitutes up to 97 percent of the alveolar surface area?

<p>Type I alveolar cells (C)</p> Signup and view all the answers

What is the diameter of an alveolus?

<p>200 μm (D)</p> Signup and view all the answers

What structure opens into a cluster of alveoli?

<p>Alveolar duct (B)</p> Signup and view all the answers

What type of cell is an alveolar macrophage?

<p>Phagocytic immune cell (B)</p> Signup and view all the answers

Which component of the alveolar wall allows for the elasticity during air intake?

<p>Elastic basement membrane (B)</p> Signup and view all the answers

Which of the following is NOT a function of the respiratory system?

<p>Regulating body temperature (C)</p> Signup and view all the answers

What structures are included in the conducting zone of the respiratory system?

<p>Trachea, bronchi, and nasal cavity (B)</p> Signup and view all the answers

Which of the following is a secondary function of portions of the respiratory system?

<p>Sensing odors (B)</p> Signup and view all the answers

Which muscle is considered part of the chest wall involved in respiration?

<p>Intercostal muscles (A)</p> Signup and view all the answers

The respiratory zone is primarily responsible for which of the following activities?

<p>Gas exchange between air and blood (B)</p> Signup and view all the answers

What role does the epithelium of the nasal passages serve?

<p>Sensing odors (C)</p> Signup and view all the answers

Which part of the respiratory system consists of the diaphragm and ribs?

<p>Chest wall (C)</p> Signup and view all the answers

What is a primary task of the conducting zone?

<p>Warms and humidifies incoming air (B)</p> Signup and view all the answers

What is the primary function of pleural fluid?

<p>To serve as a lubricant and adhesive for lung movement. (B)</p> Signup and view all the answers

How many lobes does the right lung consist of?

<p>Three lobes. (C)</p> Signup and view all the answers

What is the significance of the cardiac notch?

<p>It allows space for the heart. (C)</p> Signup and view all the answers

What separates the lobes of the lungs?

<p>Fissures. (C)</p> Signup and view all the answers

Which part of the lung is responsible for the exchange of gases?

<p>Alveoli. (B)</p> Signup and view all the answers

Which type of blood does the pulmonary artery carry to the lungs?

<p>Deoxygenated blood. (C)</p> Signup and view all the answers

How does the sympathetic nervous system affect the airway?

<p>It causes bronchodilation. (A)</p> Signup and view all the answers

What do bronchopulmonary segments contain?

<p>Multiple tertiary bronchi and their own artery. (D)</p> Signup and view all the answers

What structure marks the base of the lungs?

<p>Diaphragm. (B)</p> Signup and view all the answers

What does the interlobular septum do?

<p>Separates lobules from one another. (C)</p> Signup and view all the answers

What is the role of the pleural fluid in the pleural cavity?

<p>It reduces friction between the pleura layers. (A)</p> Signup and view all the answers

Which layer of the pleura is directly attached to the lung surface?

<p>Visceral pleura (D)</p> Signup and view all the answers

What determines the size of the lungs during ventilation?

<p>Transpulmonary pressure (C)</p> Signup and view all the answers

What does Boyle's law describe regarding gas behavior?

<p>Pressure increases when volume decreases. (C)</p> Signup and view all the answers

What is the primary mechanism driving pulmonary ventilation?

<p>Pressure differences (B)</p> Signup and view all the answers

How does the pleurae protect the lungs during organ movement?

<p>By creating cavities that separate organs (B)</p> Signup and view all the answers

What occurs during expiration in terms of pressure relationships?

<p>Intrapleural pressure exceeds atmospheric pressure. (C)</p> Signup and view all the answers

What role do sensory nerve fibers from the vagus nerve play in respiratory control?

<p>They regulate the cough reflex. (A)</p> Signup and view all the answers

Which pressure is typically lower than intra-alveolar pressure?

<p>Intrapleural pressure (A)</p> Signup and view all the answers

What is the primary function of the pulmonary plexus?

<p>To innervate muscles and glands in the lungs. (D)</p> Signup and view all the answers

What drives pulmonary ventilation?

<p>Difference in atmospheric pressures (B)</p> Signup and view all the answers

During inspiration, air flows into the lungs because:

<p>Intra-alveolar pressure is less than atmospheric pressure (C)</p> Signup and view all the answers

What is primarily responsible for the pressure changes that result in airflow during breathing?

<p>Contraction of the diaphragm and intercostal muscles (B)</p> Signup and view all the answers

What role does pulmonary surfactant play in the alveoli?

<p>It reduces surface tension to prevent alveolar collapse (A)</p> Signup and view all the answers

What factors influence the effort required for ventilation?

<p>Airway size and thoracic wall compliance (B)</p> Signup and view all the answers

Why do the lungs remain passive during breathing?

<p>They rely on pleural fluid for movement. (D)</p> Signup and view all the answers

Increasing airway resistance will result in:

<p>Decreased air flow during both inhalation and exhalation (A)</p> Signup and view all the answers

What is the significance of thoracic wall compliance in breathing?

<p>It affects the ease of lung expansion. (B)</p> Signup and view all the answers

What happens to the intra-alveolar pressure during expiration?

<p>It becomes greater than atmospheric pressure. (B)</p> Signup and view all the answers

Which condition would most likely disrupt normal airflow during breathing?

<p>Decreased diaphragm contraction (A)</p> Signup and view all the answers

What is the relationship between pressure and volume as described by Boyle's law?

<p>Pressure decreases as volume increases. (D)</p> Signup and view all the answers

If the volume of a gas in a container doubles, what happens to the pressure?

<p>It decreases by half. (C)</p> Signup and view all the answers

What is the typical intrapleural pressure throughout the breathing cycle?

<p>–4 mmHg (D)</p> Signup and view all the answers

What occurs when gas molecules migrate between containers with differing pressures?

<p>They move from higher pressure to lower pressure. (D)</p> Signup and view all the answers

Which of the following accurately describes intra-alveolar pressure?

<p>It fluctuates during different phases of breathing. (D)</p> Signup and view all the answers

What primarily determines the formation of negative intrapleural pressure?

<p>Competing forces between the elasticity of the lungs and surface tension in the pleural cavity. (B)</p> Signup and view all the answers

How does an increase in pleural fluid affect intrapleural pressure?

<p>It decreases the negative intrapleural pressure. (D)</p> Signup and view all the answers

What happens during inhalation to the intra-alveolar pressure?

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

According to Boyle's law, what formula relates pressure and volume?

<p>P1V1 = P2V2 (D)</p> Signup and view all the answers

In which state is the intrapleural pressure generally found compared to intra-alveolar pressure?

<p>It is always lower. (B)</p> Signup and view all the answers

Flashcards

Respiratory System Organs

Lungs, conducting airways, parts of the CNS controlling respiration, and the chest wall (muscles and rib cage) make up this system.

Respiratory System Functions

Obtaining oxygen, delivering it to cells, and removing carbon dioxide produced by the body are the main purposes.

Conducting Zone

Passages for air to move in and out of lungs (nose, pharynx, trachea, bronchi, some bronchioles).

Conducting Zone Function

Warming, humidifying, and filtering incoming air; route for airflow.

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Respiratory Zone

Lungs' structures directly involved in gas exchange (respiratory bronchioles and alveoli).

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Respiratory Zone Function

Gas exchange takes place here.

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Non-vital Respiratory System Functions

Sensing odors, speech, and straining (e.g., childbirth).

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Conducting Zone vs. Respiratory Zone

Conducting zone moves air, respiratory zone exchanges gases.

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Bronchial Epithelium

The tissue lining the bronchial tubes, capable of metabolizing some airborne carcinogens.

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Respiratory Zone

Part of the lungs where gas exchange occurs.

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Alveolus

Small, grape-like sac in the lungs where gas exchange happens.

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Alveolar Duct

Tube connecting an alveolus to an alveolar sac.

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Type I Alveolar Cell

Thin, squamous epithelial cell forming most of the alveolar surface, allowing gases through.

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Type II Alveolar Cell

Produces surfactant, a substance that reduces surface tension in alveoli.

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Alveolar Macrophage

Immune cell in the alveoli which removes debris and pathogens.

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Respiratory Membrane

Thin, elastic structure allowing gases to pass between alveoli and capillaries efficiently.

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Pleural Fluid Function

Lubricates lungs to reduce friction during breathing and adheres lungs to chest wall for smooth ventilation.

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Lung Shape

Pyramid-shaped, paired organs connected to the trachea by bronchi.

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Diaphragm's Role in Lungs

Dome-shaped muscle at lung base, vital for breathing.

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Cardiac Notch Location

Indentation on left lung surface for heart space.

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Lung Lobes

Separated segments within each lung (3 in right, 2 in left), divided by fissures.

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Bronchopulmonary Segments

Lobe divisions receiving air from tertiary bronchus and blood from its own artery.

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Pulmonary Lobule

Subdivisions of a lung, branching from bronchi to bronchioles.

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Interlobular Septa

Connective tissue walls separating pulmonary lobules.

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Pulmonary Artery Function

Carries deoxygenated blood from heart to lungs.

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Respiratory Membrane Location

Where the capillary wall meets the alveolar wall, allowing gas exchange.

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Pulmonary Ventilation

The process of breathing, moving air in and out of the lungs.

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Intra-alveolar Pressure

Pressure inside the alveoli (air sacs).

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Intrapleural Pressure

Pressure within the pleural cavity (space surrounding the lungs).

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Transpulmonary Pressure

Difference between intra-alveolar and intrapleural pressure. Determines lung size.

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Pleural Fluid

Lubricating fluid between visceral and parietal pleurae.

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Visceral Pleura

Inner layer of pleurae, covering the lungs.

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Parietal Pleura

Outer layer of pleurae, lining the chest cavity.

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Atmospheric Pressure

Pressure exerted by the air outside the body.

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Boyle's Law

Gas pressure and volume are inversely related—smaller volume means higher pressure.

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Inspiration

The act of inhaling air (drawing air into the lungs).

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Boyle's Law

Pressure of a gas is inversely proportional to its volume at constant temperature.

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Intra-alveolar pressure

Pressure inside the alveoli, equal to atmospheric pressure during breathing.

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Intrapleural pressure

Pressure within the pleural cavity, always negative to intra-alveolar pressure.

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Negative pressure

Pressure lower than atmospheric pressure, important for breathing.

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Positive pressure

Pressure higher than atmospheric pressure.

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Atmospheric pressure

Pressure exerted by the air surrounding us, a reference point for other pressures.

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Lung Elasticity

The tendency of the lungs to return to their original shape after stretching.

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Alveolar fluid surface tension

The force that water molecules create inside the alveoli.

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P1V1 = P2V2

Formula representing Boyle's Law, relating initial and final pressure and volume.

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Competing forces

Forces acting against and in favor of lung collapse/expansion.

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Intra-alveolar pressure

Pressure inside the alveoli (air sacs in the lungs).

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Atmospheric pressure

Pressure of the air surrounding the body.

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Transpulmonary pressure

Difference between intrapulmonary and intrapleural pressures; it keeps the lungs inflated

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Pulmonary ventilation

Movement of air into and out of the lungs.

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Pressure gradient

Difference in pressure that drives air flow.

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Thoracic wall compliance

How easily the chest wall stretches under pressure.

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Pulmonary surfactant

Substance that reduces surface tension in alveoli, preventing collapse.

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Resistance (breathing)

Forces that hinder airflow and gas flow.

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Airway size

Diameter of airways, a major factor affecting resistance during breathing.

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Intrapleural pressure

Pressure in the space between the lungs and the chest wall.

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Study Notes

Introduction to the Respiratory System

  • The respiratory system is made up of the lungs, conducting airways, and parts of the central nervous system (CNS) controlling respiration.
  • The chest wall includes the muscles of respiration (diaphragm, intercostals, and abdominal muscles), and the rib cage.

Main Functions of the Respiratory System

  • The main functions are obtaining oxygen (Oâ‚‚) from the environment, delivering Oâ‚‚ to cells, and removing carbon dioxide (COâ‚‚) produced by cellular metabolism.
  • Parts of the system also have non-vital functions, such as sensing odors, speech production, and straining (e.g., during childbirth or coughing).

Major Areas of the Respiratory System

  • Conducting zone: Includes passageways for air into and out of the lungs (nasal cavity, pharynx, trachea, bronchi, most bronchioles). It doesn't involve gas exchange.
  • Respiratory zone: Consists of structures in the lung directly involved in gas exchange (respiratory bronchioles, alveoli).

Organs and Structures of the Respiratory System

  • Upper Respiratory Tract: Nose (airway), Mouth (food and air), Epiglottis (larynx cover), Nasal Cavity (filters, warms, and moistens air), Pharynx (throat, common passage), Larynx (voice box, sound production), Trachea (windpipe).
  • Lower Respiratory Tract: Pleural Membranes (lungs and chest lining), Lungs (gas exchange), Intercostal Muscles (move ribs), Rib (supports respiration), Diaphragm (skeletal muscle, respiration), Bronchi (branching airways), Alveoli (air sacs, gas exchange).

The Conducting Zone

  • Key functions include providing a pathway for incoming and outgoing air, removing debris and pathogens, and warming and humidifying the inhaled air.
  • Structures within the conducting zone have additional functions, such as sensing odors in the nasal passages and metabolizing airborne carcinogens in the bronchial epithelium.

The Respiratory Zone

  • Begins where a terminal bronchiole gives rise to respiratory bronchioles — the smallest type.
  • Each respiratory bronchiole creates 3 alveolar ducts, each leading to a cluster of alveoli.
  • Alveoli are small, grape-like sacs that are responsible for gas exchange.
  • Bronchioles lead to alveolar sacs within the respiratory zone, where gas exchange occurs.

Alveoli

  • Alveoli are thin-walled, grape-like sacs embedded in a network of capillaries.
  • Each alveolus is approximately 200 μm in diameter.
  • Alveolar ducts open into a cluster of alveoli.
  • The alveolar walls are very thin, which allows rapid gas exchange.
  • Alveoli are connected to each other by alveolar pores for maintaining even air pressure.

The Alveolar Wall

  • The alveolar wall is composed of three main cell types.
    • Type I alveolar cells: Thin, squamous epithelial cells that form the majority of the surface area, high gas permeability.
    • Type II alveolar cells: Interspersed among Type I cells, produce pulmonary surfactant – reduces surface tension.
    • Alveolar macrophages: Mobile phagocytic cells within the alveolar wall, removes debris.

The Respiratory Membrane

  • The respiratory membrane is formed by the thin alveolar and capillary walls and their basement membranes.
  • It is very thin, facilitating effortless gas diffusion (across the membrane).

The Lungs

  • A major organ of the respiratory system involved in gas exchange.
  • Each lung has conducting and respiratory zones.
  • The exchange happens across an extensive epithelial surface area (about 70 square meters).

Review of the Lungs

  • Paired and separated into lobes (left has two, right has three).
  • Crucial for blood circulation and oxygen transport.
  • The pulmonary artery delivers deoxygenated blood to the capillaries surrounding the alveoli.
  • Pulmonary veins carry oxygenated blood back to the heart.
  • Lungs are innervated by sympathetic and parasympathetic nervous systems controlling bronchodilation and bronchoconstriction, respectively.

Gross Anatomy of the Lungs

  • Pyramid shaped, connected to the trachea by bronchi.
  • Inferior surface is bordered by the diaphragm.
  • Right lung is shorter and wider than left lung.
  • The left lung has a cardiac notch to accommodate the heart position.

Gross Anatomy of the Lungs (continued)

  • Lobes—right has three, left has two, separated by fissures.
  • Each lobe has bronchopulmonary segments.
  • Bronchopulmonary segments are further subdivided into lobules.

Blood Supply and Nervous Innervation

  • Blood supply is a transport system for gases throughout the body.
  • Specialized for gas exchange and follows the bronchi to the alveoli.
  • The pulmonary artery brings in deoxygenated blood.
  • The pulmonary veins return oxygenated blood to the heart.
  • The nervous system controls bronchodilation/constriction.

Pleura of the Lungs

  • Double membrane surrounding each lung (visceral and parietal).
  • Fluid between them (pleural fluid) lubricates and prevents friction during breathing.
  • Creates a cavity, preventing interference between organs.

Pressure Relationships

  • Inspiration/exhalation depends on differences in atmosphere and lung pressure.
  • Atmospheric pressure is the force exerted by gases.
  • Intra-alveolar pressure is the pressure within the alveoli, always equal to atmospheric pressure.
  • Intrapleural pressure is the pressure within the pleural cavity, always slightly lower than intra-alveolar pressure.
  • Transpulmonary pressure is the difference between intrapulmonary and intrapleural pressures, determining lung size.

Mechanisms of Breathing

  • Intra-alveolar and intrapleural pressure changes control breathing; they are dependent on certain physical features of the lung.
  • Air moves from higher to lower pressure.

Physical Factors Affecting Ventilation

  • Lung elasticity and surface tension of alveolar fluid affect movement (inward pull).
  • Thoracic wall elasticity and tension produce counter-force (outward pull)
  • The balance of these forces influences pulmonary volume and pressure.
  • Resistance in the airways affects the ease of gas movement (dependent on airway tube/diameter size).

Importance of Pulmonary Surfactant

  • Surfactant reduces surface tension in alveoli, enabling easier inflation.
  • This prevents alveolar collapse during exhalation.

Thoracic Wall Compliance

  • The wall's ability to expand and contract facilitates breathing.
  • Compliant tissue allows for expansion to increase lung size.

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Description

This quiz explores the components and functions of the respiratory system. It covers the anatomy of the respiratory tract, the roles of various muscles, and the processes involved in gas exchange. Test your knowledge on how the respiratory system supports vital functions in the body.

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