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What is the primary function of the bronchioles?
What is the primary function of the bronchioles?
The larynx is responsible for connecting the nasal cavity and the trachea.
The larynx is responsible for connecting the nasal cavity and the trachea.
False
What do ciliated cells in the airways help accomplish?
What do ciliated cells in the airways help accomplish?
They help trap foreign objects and move mucus towards the pharynx.
The trachea is kept open by __________ rings.
The trachea is kept open by __________ rings.
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Match the structures with their functions:
Match the structures with their functions:
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What is the primary function of the respiratory system?
What is the primary function of the respiratory system?
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The term 'ventilation' refers to the exchange of gases between the atmosphere and the cells of the body.
The term 'ventilation' refers to the exchange of gases between the atmosphere and the cells of the body.
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What is the process called in which O2 is exchanged for CO2 between the lungs and blood?
What is the process called in which O2 is exchanged for CO2 between the lungs and blood?
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The primary role of the ______ is to transport air to and from the lungs.
The primary role of the ______ is to transport air to and from the lungs.
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Match the following respiratory terms with their definitions:
Match the following respiratory terms with their definitions:
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Which system relaxes smooth muscle in bronchioles, increasing their diameter?
Which system relaxes smooth muscle in bronchioles, increasing their diameter?
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Lung compliance depends only on the elastic fibers present in the lung.
Lung compliance depends only on the elastic fibers present in the lung.
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What is the role of surfactant in the alveoli?
What is the role of surfactant in the alveoli?
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After normal expiration, there always remains air in the lungs called _____ Volume.
After normal expiration, there always remains air in the lungs called _____ Volume.
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Match the respiratory patterns with their definitions:
Match the respiratory patterns with their definitions:
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What is the maximum amount of air that can be inhaled and exhaled called?
What is the maximum amount of air that can be inhaled and exhaled called?
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Polypnea is characterized by increased depth of breath while exercising.
Polypnea is characterized by increased depth of breath while exercising.
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What measurement does a spirometer provide?
What measurement does a spirometer provide?
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What is the main mechanism of inspiration in the respiratory system?
What is the main mechanism of inspiration in the respiratory system?
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The velocity of airflow increases dramatically as air moves from the trachea to the respiratory zone.
The velocity of airflow increases dramatically as air moves from the trachea to the respiratory zone.
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What substance is produced by type 2 epithelial cells in the alveoli?
What substance is produced by type 2 epithelial cells in the alveoli?
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The primary purposes of ciliated epithelial cells in the bronchi are to _____ and _____ mucus.
The primary purposes of ciliated epithelial cells in the bronchi are to _____ and _____ mucus.
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Match the following terms with their definitions:
Match the following terms with their definitions:
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Which of the following contributes to airway resistance during airflow?
Which of the following contributes to airway resistance during airflow?
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The pleural membranes cover the lungs and provide lubrication to prevent friction during breathing.
The pleural membranes cover the lungs and provide lubrication to prevent friction during breathing.
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What is the role of defensins in the airways?
What is the role of defensins in the airways?
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The pressure gradient for airflow is created by changes in ________.
The pressure gradient for airflow is created by changes in ________.
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Which of the following factors primarily influences airflow in the respiratory system?
Which of the following factors primarily influences airflow in the respiratory system?
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Which of the following best describes the primary function of the respiratory system?
Which of the following best describes the primary function of the respiratory system?
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Ventilation and gas exchange are the same processes.
Ventilation and gas exchange are the same processes.
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What is the term used for the process of oxidation of cellular molecules that produces CO2, water, and ATP?
What is the term used for the process of oxidation of cellular molecules that produces CO2, water, and ATP?
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The __________ receives 100% of the cardiac output from the right heart.
The __________ receives 100% of the cardiac output from the right heart.
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Match each respiratory term with its corresponding description:
Match each respiratory term with its corresponding description:
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What is the primary function of the airways in the respiratory system?
What is the primary function of the airways in the respiratory system?
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The epiglottis prevents food from entering the bronchi during swallowing.
The epiglottis prevents food from entering the bronchi during swallowing.
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What structure connects the pharynx to the trachea?
What structure connects the pharynx to the trachea?
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Air is warmed to ________ body temperature before reaching the alveoli.
Air is warmed to ________ body temperature before reaching the alveoli.
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Match the following parts of the respiratory system with their descriptions:
Match the following parts of the respiratory system with their descriptions:
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Which statement accurately describes lung compliance?
Which statement accurately describes lung compliance?
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Surfactant increases the surface tension in the alveoli.
Surfactant increases the surface tension in the alveoli.
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What are the four main pulmonary volumes measured by a spirometer?
What are the four main pulmonary volumes measured by a spirometer?
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The mixture that reduces surface tension in the alveoli is called ______.
The mixture that reduces surface tension in the alveoli is called ______.
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Match the following respiratory patterns with their descriptions:
Match the following respiratory patterns with their descriptions:
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What does the Inspiratory Reserve Volume (IRV) refer to?
What does the Inspiratory Reserve Volume (IRV) refer to?
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The presence of hydrogen bonds in water molecules tends to increase alveolar surface area.
The presence of hydrogen bonds in water molecules tends to increase alveolar surface area.
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What condition in piglets is associated with inadequate production of surfactant?
What condition in piglets is associated with inadequate production of surfactant?
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What primarily reduces the velocity of airflow in the respiratory zone?
What primarily reduces the velocity of airflow in the respiratory zone?
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Inspiration is a passive mechanism that occurs when the diaphragm relaxes.
Inspiration is a passive mechanism that occurs when the diaphragm relaxes.
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What is the main function of cilia in the airways?
What is the main function of cilia in the airways?
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The __________ is a sheet of skeletal muscle that separates the thoracic and abdominal cavities.
The __________ is a sheet of skeletal muscle that separates the thoracic and abdominal cavities.
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Match the following airway resistance factors with their effects:
Match the following airway resistance factors with their effects:
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What role do type 2 epithelial cells in the alveoli primarily serve?
What role do type 2 epithelial cells in the alveoli primarily serve?
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Expulsion of air from the lungs is primarily an active process.
Expulsion of air from the lungs is primarily an active process.
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What is the primary factor influencing airflow resistance in the respiratory system?
What is the primary factor influencing airflow resistance in the respiratory system?
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Intrapleural space is filled with a small amount of __________ to provide lubrication.
Intrapleural space is filled with a small amount of __________ to provide lubrication.
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Which of the following accurately describes Boyle's Law in relation to ventilation?
Which of the following accurately describes Boyle's Law in relation to ventilation?
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Study Notes
### Respiratory System Function
-
Main function: gas exchange for metabolism
- Transports oxygen to blood
- Removes carbon dioxide from blood
-
Secondary functions:
- Filters blood
- Chemical processing
- Defenses against pathogens (first line of defense)
- Assist venous return (respiratory pump)
Respiratory System Definitions
- Respiration: exchange of gases between the atmosphere and the cells of the body
- Ventilation: movement of air into and out of the lungs (breathing)
- Gas exchange: oxygen and carbon dioxide exchange between air in the lungs and blood
- Cellular respiration: process within cells that uses oxygen to produce energy (ATP), carbon dioxide, and water
Gas Transport Stages
- Ventilation: movement of air from atmosphere to respiratory zone
- Gas exchange: oxygen moves from the alveoli to the blood, carbon dioxide moves from the blood to the alveoli
- Circulation: oxygenated blood travels to tissues, deoxygenated blood returns to lungs
- Tissue diffusion: oxygen moves from blood to cells, carbon dioxide moves from cells to blood
- Internal respiration: cells use oxygen for metabolism, producing carbon dioxide
### Airways
-
Functions:
- Deliver gas to respiratory zone (alveoli)
- Conditions inhaled air: warms, humidifies, and filters
-
Structures:
- Nasal/Oral cavities: lined with mucous membrane that warms and humidifies air
- Pharynx: connects nasal/oral cavity to the larynx
- Larynx: connects pharynx to trachea; contains the vocal cords
- Trachea: flexible tube kept open by cartilage rings, lined with cilia and mucus cells
- Bronchi: tubes with cartilage plates to maintain shape; branch into smaller tubes
- Bronchioles: lack cartilage, rely on lung recoil to stay open; possess smooth muscle
Alveoli - The Respiratory Zone
- Clusters around terminal bronchioles
- Thin-walled, single layer of epithelial cells
- Surrounded by a capillary network
- Air is separated from blood by two cell layers (epithelium and endothelium), for optimal gas exchange
- Type 2 epithelial cells produce surfactant (reduces surface tension)
- Macrophages (immune cells) reside in alveoli and phagocytose foreign particles
Thoracic Cavity
- Location: space within the rib cage
- Boundaries: thoracic vertebrae, ribs, intercostal (between the ribs) muscles, sternum
- Diaphragm: muscle that separates the thoracic cavity from the abdominal cavity
- Mediastinum: divides the thoracic cavity into two halves, containing the heart, trachea, esophagus, vessels, and nerves
Pleural Membranes
- Location: line the lungs and the inner thoracic cavity
- Types: visceral pleura (covers the lungs) and parietal pleura (lines the chest wall)
- Intrapleural space: small space between the pleura, filled with fluid to reduce friction
Ventilation Mechanics
- Principle: air flows from high to low pressure
-
Inspiration: active process
- Diaphragm contracts, expanding the thoracic cavity
- Lung volume increases
- Negative pressure gradient is created
- Air flows into the alveoli
-
Expiration: passive process (at rest)
- Inspiratory muscles relax
- Lung recoils
- Pressure increases in alveoli
- Air flows out
Boyle's Law
- Principle: pressure and volume are inversely proportional for a gas at a constant temperature (P1V1 = P2V2)
- Inspiration: alveolar pressure is less than atmospheric pressure, air flows in
- Expiration: alveolar pressure is greater than atmospheric pressure, air flows out
Factors Influencing Ventilation
-
Airway resistance: major factor influencing ventilation
- Primarily located in the nasal cavity
- Increased turbulence increases resistance
- Diameter: reduced diameter increases resistance, parallel branches increase cross-sectional area which decreases resistance
- Autonomic nervous system controls smooth muscle in bronchioles: sympathetic relaxes (increased diameter), parasympathetic constricts (decreased diameter)
-
Lung compliance: ability of the lung to expand and recoil
- Affected by elastic fibers in the lung tissue and surface tension in the alveoli
-
Alveolar surface tension: tendency of water to minimize its surface area
- Reduced by surfactant (phospholipids, calcium, and proteins)
Pulmonary Volumes
- Spirometer: measures inhaled and exhaled air volume
- Tidal Volume (VT): volume of air moved during normal breathing
- Inspiratory Reserve Volume (IRV): additional air inhaled forcefully after normal inspiration
- Expiratory Reserve Volume (ERV): additional air exhaled forcefully after normal expiration
- Residual Volume (RV): air that remains in the lungs even after maximum exhalation
- Vital Capacity (VC): total volume of air that can be inhaled and exhaled (VT + IRV + ERV)
- Total Lung Capacity (TLC): volume of air in the lungs after maximum inhalation (VC + RV)
### Respiratory Patterns
- Eupnea: normal breathing
- Hyperpnea: increased depth or frequency (exercise)
- Polypnea: increased frequency of shallow breaths (panting)
- Dyspnea: labored breathing
- Apnea: cessation of breathing
Respiratory System Functions
- The respiratory system's primary function is gas transport for metabolism.
- This includes moving oxygen from the air into pulmonary blood.
- It also involves clearing carbon dioxide from the body.
- Non-respiratory functions include:
- Lungs receive 100% of the cardiac output from the right heart.
- Filter blood and participate in chemical processing.
- Serve a role in the first line of defense against infection.
- Facilitate venous return through the respiratory pump.
Respiratory Definitions
- Respiration: The exchange of gases between the atmosphere and the cells of the body.
- Ventilation: The movement of air to and from the lungs, also known as breathing.
- Gas Exchange: The transfer of oxygen and carbon dioxide between the air in the lungs and the blood.
- Cellular Respiration: The oxidation of cellular molecules that produces carbon dioxide, water, and ATP.
Stages of Gas Transport
- Ventilation: Bulk airflow movement that delivers air to the respiratory zone for gas exchange.
- Gas Exchange/Lung Diffusion: Gas exchange between the respiratory zone and the blood, where oxygen moves into the blood and red blood cells, while carbon dioxide moves in the reverse direction.
- Circulation/Transport: Adequate pulmonary and systemic circulation is crucial for carrying oxygen to tissues and carbon dioxide away from tissues.
- Tissue Diffusion: Passive diffusion of oxygen and carbon dioxide between red blood cells/plasma and tissue cells.
- Internal Respiration: Cellular metabolism using oxygen and producing carbon dioxide.
Airways
-
Functions:
- Delivering gas to the respiratory zone (alveoli).
- Conditioning inhaled air:
- Warming air to core body temperature.
- Humidifying air to prevent drying of the respiratory epithelium.
- Filtering and cleansing to prevent foreign objects and microorganisms from entering the lungs.
-
Structures:
-
Nasal/Oral Cavities:
- Lined with mucous membrane that warms and humidifies air.
- May include hair in nostrils for initial filtration (some species).
- Epithelium contains ciliated cells and mucus cells (goblet cells), which trap foreign objects and move mucus towards the pharynx.
- Pharynx: Connects the nasal/oral cavity to the larynx.
-
Larynx:
- Connects the pharynx to the trachea.
- Contains cartilage (glottis and epiglottis) to prevent food from entering the trachea.
- Houses the vocal cords.
-
Trachea:
- Flexible tube kept open by cartilage rings.
- Inner surface lined with ciliated and mucus cells to trap particles and move debris towards the pharynx.
-
Bronchi:
- Possess cartilage plates for structural support.
- Begins with one tube per lung (primary bronchi).
- Branch into narrower tubes with less cartilage.
-
Bronchioles:
- Lack cartilage and rely on lung recoil to maintain potency.
- Possess smooth muscle.
- Bronchi and Bronchioles: Lined with ciliated and mucus-producing cells.
-
Nasal/Oral Cavities:
Alveoli
- Clusters surrounding terminal bronchioles.
- Formed by a single layer of epithelial cells.
- Covers a large surface area in adult humans.
- Surrounded by a capillary network for efficient gas exchange.
- Air is separated from blood by two layers of cells (epithelium and endothelium) ideal for gas exchange.
- Type II epithelial cells produce surfactant, which reduces surface tension.
- Macrophages engulf small particles that reach the alveoli for immune defense.
Thoracic Cavity
- The space within the thoracic cage, enclosed by:
- Thoracic vertebrae.
- Ribs and intercostal muscles.
- Sternum.
-
Diaphragm:
- Separates the thoracic and abdominal cavities.
- Skeletal muscle and tendon sheet.
-
Mediastinum:
- Divides the thoracic cage into two halves (from spine to sternum).
- Connective tissue containing vessels, nerves, trachea, esophagus, and the heart.
- Each lung fills one half.
Pleural Membranes
- Wet epithelial surfaces that cover the lungs.
- Intrapleural space filled with a small amount of fluid, providing lubrication for friction-free lung movement.
Ventilation
- Follows the laws of physics, airflow moves from high to low pressure, driven by pressure differences (ΔP).
- Resistance to flow (R) is caused by friction between air particles and the airways.
- Similar to blood flow: Flow (F) = ΔP/R
- Increased resistance (R) requires an increase in pressure difference (ΔP) to maintain airflow.
- Decreased pressure difference(ΔP) requires a decreased resistance (R) to maintain airflow.
Ventilation Pump (Mechanics)
- Respiratory muscle compression/expansion of the lungs controls pressure differences (ΔP).
-
Inspiration (Active)
- Diaphragm contracts, expanding thoracic volume, creating negative pressure.
- Lung expansion and increased alveolar volume create a negative pressure gradient, facilitating airflow down the airways.
-
Expiration (Passive at Rest)
- At the end of inspiration, inspiratory muscles relax, allowing the lungs to recoil.
- This increases pressure in the alveoli, creating a pressure gradient from the alveoli to the atmosphere.
- Diaphragm is the most important muscle at rest.
Boyle's Law
- For a gas at a constant temperature, pressure and volume are inversely related: P1V1 = P2V2
- Increased volume (V) leads to decreased pressure (P).
- Decreased volume (V) leads to increased pressure (P).
- During inspiration:
- P alveolar < P atmosphere, air flows into the airways until P alveolar = P atmosphere.
- During expiration (muscle relaxation and lung recoil):
- P alveolar > P atmosphere, air flows out until equilibrium is reached.
Factors Influencing Ventilation
- Air flow concept is similar to blood flow (F = ΔP/R).
- Resistance in airways is typically small, making ΔP the major influencing factor.
-
Airway Resistance:
- Primarily occurs in the nasal cavity (due to diseases, obstructions).
- During exercise, animals mainly use their mouth to reduce resistance (except horses who flare their nostrils).
- Turbulence increases resistance.
- Decreased diameter with branching increases resistance, but parallel branching increases cross-sectional area, compensating for the increased resistance.
- The autonomic nervous system controls smooth muscle in bronchioles:
- Sympathetic relaxation = increased diameter.
- Parasympathetic contraction = decreased diameter.
Lung Compliance
- The ability of the lungs to expand and recoil.
- Depends on:
- Elasticity of the lung tissues.
- Elasticity of the thoracic cage.
- Surface tension in the alveoli.
Alveolar Surface Tension
- Caused by hydrogen bonds in water molecules in contact with air (contributes to the shape of water droplets).
- Tends to reduce the surface area.
- Reduced by surfactant:
- Mixture of phospholipids, calcium ions (Ca2+), and proteins.
- Phospholipids decrease the surface tension between hydrogen molecules.
- Insufficient surfactant production can lead to increased surface tension, increased resistance to distension, and decreased ventilation (e.g., Barker syndrome in piglets).
Pulmonary Volumes
- Spirometer: Measures volumes of air inhaled and exhaled (spirogram is the recording).
- Tidal Volume (VT): Airflow through the airways during a normal breath.
- Inspiratory Reserve Volume (IRV): Additional air that can be inhaled with maximal effort beyond normal inspiration.
- Expiratory Reserve Volume (ERV): Additional air that can be exhaled with maximal effort beyond normal expiration.
- Residual Volume (RV): Air remaining in the lungs after maximal expiration.
- Vital Capacity (VC): The maximum amount of air that can be inhaled and exhaled (IRV + VT + ERV).
- Total Lung Capacity (TLC): The total amount of air the lungs can hold (RV + VC).
Respiratory Patterns
- Eupnea: Normal breathing.
- Hyperpnea: Increased depth or frequency of breathing (exercise).
- Polypnea: Increased frequency of shallow breaths (panting).
- Dyspnea: Labored breathing.
- Apnea: Cessation of breathing.
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Description
Explore the essential functions and definitions related to the respiratory system. This quiz covers gas exchange, ventilation, and the stages of gas transport that facilitate respiration. Understand how the respiratory system supports metabolism and defends against pathogens.
