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Questions and Answers
What is the role of surfactant in the alveoli?
What is the role of surfactant in the alveoli?
What is the primary function of the respiratory system?
What is the primary function of the respiratory system?
According to Boyle's law, how does the pressure of a gas behave at a constant temperature?
According to Boyle's law, how does the pressure of a gas behave at a constant temperature?
Which structure is responsible for preventing food from entering the larynx?
Which structure is responsible for preventing food from entering the larynx?
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Which muscle contracts during inspiration?
Which muscle contracts during inspiration?
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What is the main role of Type II alveolar cells?
What is the main role of Type II alveolar cells?
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What is the maximum air exhaled after a maximum inhalation called?
What is the maximum air exhaled after a maximum inhalation called?
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Which of the following components is part of the conducting zone of the respiratory system?
Which of the following components is part of the conducting zone of the respiratory system?
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How is lung compliance defined?
How is lung compliance defined?
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Which term describes the movement of air into the lungs?
Which term describes the movement of air into the lungs?
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What is the typical tidal volume during one respiratory cycle?
What is the typical tidal volume during one respiratory cycle?
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What does anatomical dead space refer to?
What does anatomical dead space refer to?
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What structure branches off from the trachea to lead into the lungs?
What structure branches off from the trachea to lead into the lungs?
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How does increased pressure affect air movement in the lungs?
How does increased pressure affect air movement in the lungs?
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What is found in the pleural cavity that aids in breathing?
What is found in the pleural cavity that aids in breathing?
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Which of these structures does NOT participate in sound production?
Which of these structures does NOT participate in sound production?
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What is the significance of dead space in the respiratory system?
What is the significance of dead space in the respiratory system?
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Which law explains that gas solubility in liquid is proportional to the pressure of the gas?
Which law explains that gas solubility in liquid is proportional to the pressure of the gas?
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How is carbon dioxide transported in the blood?
How is carbon dioxide transported in the blood?
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What role does the medulla oblongata play in breathing regulation?
What role does the medulla oblongata play in breathing regulation?
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Which condition is characterized by destruction of smaller airways and difficulty exhaling?
Which condition is characterized by destruction of smaller airways and difficulty exhaling?
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What typically exacerbates asthma symptoms?
What typically exacerbates asthma symptoms?
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What is alveolar ventilation calculated from?
What is alveolar ventilation calculated from?
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What is the function of the pons in breathing regulation?
What is the function of the pons in breathing regulation?
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Study Notes
Respiratory System Functions
- Takes in oxygen and removes carbon dioxide
- Regulates blood pH by removing carbon dioxide
- Warms and moistens inhaled air
- Filters particles from inhaled air
- Provides a sense of smell
- Produces sound by moving air past vocal cords
Key Terms
- Ventilation: Movement of air into and out of the lungs
- Inspiration (Inhalation): Breathing in
- Expiration (Exhalation): Breathing out
- Respiration: Gas exchange
- Cellular Respiration: Use of oxygen by cells to make ATP
Functional Divisions
- Conducting Zone: Moves air into and out of the lungs
- Components: Nose, Mouth, Pharynx, Larynx, Trachea, Bronchi, Bronchioles, Terminal Bronchioles
- Respiratory Zone: Where gas exchange occurs
- Components: Alveolar Ducts, Alveoli
Anatomy of the Respiratory System
- Pharynx (Throat): Pathway for air and food
- Eustachian Tube: Connects to the middle ear; equalizes air pressure
- Epiglottis: Covers larynx to prevent food entry
- Larynx (Voice Box): Contains vocal cords
- Trachea (Windpipe): Supported by cartilage rings, lined with mucous membrane
- Bronchi: Split from trachea, leading into lungs
- Vocal Folds of the Larynx
- Inside the larynx, 2 vocal cords
- False Vocal Cords: Upper pair; no sound production
- True Vocal Cords: Lower pair; involved in sound production
- Glottis: Opening between true vocal cords
- The Trachea
- Located anterior to the esophagus, surrounded by incomplete rings of hyaline cartilage to keep airway open
- Lined with mucous membrane and ciliated epithelium; contains goblet cells that produce mucus
- Branches into left and right bronchi at T5
- The Pleura
- Pleura: mucous membrane, surrounds the lungs
- Visceral Pleura: Covers lungs
- Parietal Pleura: Covers inside of the thoracic cavity
- Pleural Cavity: Small space between the 2 pleuras, filled with fluid to prevent friction during breathing
- The Alveoli
- Sites of gas exchange, surrounded by capillaries and lymph vessels
- Type I Alveolar Cells: Comprise most of the wall lining for gas exchange
- Type II Alveolar Cells: Secrete surfactant (detergent-like substance) to maintain alveolar stability
- Surfactant creates surface tension which keeps the alveoli open; without it, they would collapse from the pull of the hydrogen bonds in the water molecules (within the alveoli)
Pulmonary Ventilation and Pressure Changes
- Occurs due to pressure changes in the thoracic cavity
- Muscles used for quiet (regular) breathing:
- Inspiration: Diaphragm and external intercostals contract
- Expiration: Diaphragm and intercostals relax
Ventilation Compliance
- Compliance can be considered the inverse of stiffness
- Two major determinants of lung compliance:
- "Stretchability" of the lung tissues
- Surface tension at the air-water interfaces within the alveoli - surfactant
- Recoil is required for the lungs to push the air out of the lungs during exhalation
Lung Volumes and Capacities
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The volume of our lungs is directional proportional to the size of a person's body.
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This ratio is approximately 8 to 10 mL/kg of body weight.
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4 distinct lung (respiratory) volumes:
- Tidal Volume (TV): volume of air that enters or leaves the lungs during one respiratory cycle (~500mL)
- Inspiratory Reserve Volume (IRV): Extra amount of air inhaled, in addition to tidal volume, during forced inspiration (~3 L)
- Expiratory Reserve Volume (ERV): Extra amount of air exhaled, beyond tidal volume, during maximal forced expiration (~1.2 L)
- Residual Volume (RV): Air left in lungs after maximal exhalation (~1.2L)
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Respiratory capacities: combinations of 2 or more respiratory volumes:
- Inspiratory capacity (IC)
- Vital Capacity (VC)
- Total Lung Capacity (TLC)
Alveolar Ventilation (AV)
- Alveolar Ventilation refers to the amount of air that reachesthe alveoli in one minute:
- AV = (tidal volume – dead space) X respiration rate
- We also have alveolar dead space, if some alveoli have less blood flow at that time.
Gas Exchange and Transport
- Dalton's Law: Total pressure is the sum of partial pressures of each gas
- Henry's Law: Gas solubility in liquid is proportional to the pressure of the gas
- Carbon Dioxide Transport: In 3 ways:
- 7-10% dissolved in plasma
- 25-30% bound to hemoglobin
- 60-65% converted to bicarbonate ions
Anatomical dead space
- located in the bronchial tree and is not involved in gas exchange
- the air that enters the respiratory tract but does not reach the alveoli and instead stays in this space (~150 mL)
COPD and Asthma
- Chronic obstructive pulmonary disease (COPD): Includes emphysema and chronic bronchitis
- Chronic bronchitis: excessive mucus production in the bronchi and chronic inflammatory changes in the small airways. The cause of obstruction is an accumulation of mucus in the airways
- Emphysema: destruction and collapse of the smaller airways and loss of elastic ability to exhale
- Asthma: a disease characterized by intermittent episodes in which airway smooth muscle contracts strongly, markedly increasing airway resistance. The basic defect in asthma is chronic inflammation of the airways; caused by allergies, viral infections, and sensitivity to environmental factors
Regulation of Breathing
- Primarily regulated by the medulla oblongata
- Sends signals to the diaphragm and external intercostal muscles to contract
- Medulla has pacemaker cells that control the rhythm of breathing
- Pons: Affects the rate of breathing by inhibiting or stimulating medulla oblongata
Summary of Key Points
- Functions include gas exchange, pH regulation, air filtration, sound production, and olfaction
- Structures involved encompass nasal cavity, pharynx, larynx, trachea, bronchi, and alveoli
- Gas exchange dynamics are influenced by pressures, partial pressures, and chemical concentrations in blood.
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Description
Test your knowledge on the functions and anatomy of the respiratory system. This quiz covers key terms, functional divisions, and components essential for respiratory health. Understand how various parts work together to facilitate breathing and gas exchange.
