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Questions and Answers
Which of the following steps involves gas exchange between lung tissues and blood?
Which of the following steps involves gas exchange between lung tissues and blood?
The primary function of the respiratory system is to eliminate carbon monoxide.
The primary function of the respiratory system is to eliminate carbon monoxide.
False
What is the role of the conducting zone in the respiratory system?
What is the role of the conducting zone in the respiratory system?
It directs air toward the respiratory zone and filters, warms, and humidifies air as it enters the body.
The respiratory system includes the _________ which is responsible for vocal sounds.
The respiratory system includes the _________ which is responsible for vocal sounds.
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Match the following respiratory structures with their functions:
Match the following respiratory structures with their functions:
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What are the three steps involved in respiration in the human body?
What are the three steps involved in respiration in the human body?
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The lower respiratory system includes the nasal cavity.
The lower respiratory system includes the nasal cavity.
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What percentage of carbon dioxide is transported as bicarbonate in the blood?
What percentage of carbon dioxide is transported as bicarbonate in the blood?
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The primary role of hemoglobin is to transport carbon dioxide rather than oxygen.
The primary role of hemoglobin is to transport carbon dioxide rather than oxygen.
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What is the effect of increased acidity on hemoglobin's affinity for oxygen?
What is the effect of increased acidity on hemoglobin's affinity for oxygen?
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When fully saturated with oxygen, hemoglobin is considered _____ saturated.
When fully saturated with oxygen, hemoglobin is considered _____ saturated.
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Match the following components with their respective roles in respiration:
Match the following components with their respective roles in respiration:
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What structure divides the nasal cavity into left and right halves?
What structure divides the nasal cavity into left and right halves?
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The false vocal cords are responsible for producing sound.
The false vocal cords are responsible for producing sound.
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What is the primary function of the tonsils?
What is the primary function of the tonsils?
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The larynx contains the ________ cartilage which is also known as the Adam's apple.
The larynx contains the ________ cartilage which is also known as the Adam's apple.
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Which of the following cartilages serves as a landmark for tracheotomies?
Which of the following cartilages serves as a landmark for tracheotomies?
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Match the following structures with their corresponding functions:
Match the following structures with their corresponding functions:
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The bronchi branch into smaller tubes known as terminal bronchioles.
The bronchi branch into smaller tubes known as terminal bronchioles.
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What type of epithelium lines the oropharynx?
What type of epithelium lines the oropharynx?
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The airway is maintained ________ by the cartilage that forms the trachea.
The airway is maintained ________ by the cartilage that forms the trachea.
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What is the role of pleural fluid in the lungs?
What is the role of pleural fluid in the lungs?
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The cardiac notch decreases the size of the left lung by 20%.
The cardiac notch decreases the size of the left lung by 20%.
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What is the medical term for the space between the lungs?
What is the medical term for the space between the lungs?
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The _________ separates the superior and inferior lobes of the lungs.
The _________ separates the superior and inferior lobes of the lungs.
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Match the following parts of the lungs with their functions:
Match the following parts of the lungs with their functions:
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Which cells in the alveoli are responsible for secreting surfactant?
Which cells in the alveoli are responsible for secreting surfactant?
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The pulmonary arteries carry oxygenated blood to the lungs.
The pulmonary arteries carry oxygenated blood to the lungs.
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Name one common condition that can compromise the patency of airways.
Name one common condition that can compromise the patency of airways.
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The pressure in the lungs must be lowered _______ atmospheric pressure for inhalation to occur.
The pressure in the lungs must be lowered _______ atmospheric pressure for inhalation to occur.
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How many segmental bronchi are found in the right lung?
How many segmental bronchi are found in the right lung?
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What percentage of inhaled air is attributed to the depression of the diaphragm during breathing?
What percentage of inhaled air is attributed to the depression of the diaphragm during breathing?
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Exhalation is an active process that requires energy from respiratory muscles.
Exhalation is an active process that requires energy from respiratory muscles.
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What term describes the distensibility of elastic tissues in the lungs?
What term describes the distensibility of elastic tissues in the lungs?
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The process of gas exchange between the alveoli and the blood is known as __________ respiration.
The process of gas exchange between the alveoli and the blood is known as __________ respiration.
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Match the following concepts with their descriptions:
Match the following concepts with their descriptions:
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What primarily affects the rate of passive diffusion in the lungs?
What primarily affects the rate of passive diffusion in the lungs?
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Carbon dioxide is 24 times less soluble in water than oxygen.
Carbon dioxide is 24 times less soluble in water than oxygen.
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Which muscles assist in active exhalation during vigorous activities?
Which muscles assist in active exhalation during vigorous activities?
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A lack of __________ in the pleural cavity can lead to decreased lung volume.
A lack of __________ in the pleural cavity can lead to decreased lung volume.
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What is the primary factor that determines the resistance of airflow in the respiratory system?
What is the primary factor that determines the resistance of airflow in the respiratory system?
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Study Notes
Respiration
- Respiration is the process of acquiring oxygen and eliminating carbon dioxide.
- Three steps in the human respiratory system:
- Pulmonary ventilation: Gas exchange between the atmosphere and lung tissues.
- External respiration: Gas exchange between lung tissues and blood.
- Internal respiration: Gas exchange between blood and body tissues.
- Functions of the respiratory system:
- Exchanges gases.
- Regulates blood pH.
- Permits vocal sounds, sense of smell, filters inhaled air, and excretes wastes during exhalation.
- Oto(rhino)laryngology is the study of the respiratory system.
- Why do cells need oxygen? Aerobic cellular respiration.
- Three respiratory surfaces in the body.
- External respiration happens at the alveoli.
Anatomy of the Respiratory System
- The respiratory system includes
- Upper respiratory system: Includes nose, nasal cavity, pharynx and associated structures.
- Lower respiratory system: Includes larynx, trachea, bronchi, and lungs.
- Functional Zones of the respiratory system:
- Conducting zone: Directs air to the respiratory zone, filters, warms, and humidifies air.
- Respiratory zone: Site of gas exchange, including respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.
- The nose: Made of bone, cartilage, and connective tissue (CT), contains the nasal cavity Air enters via external nares (nostrils).
- Nasal Cavity: Interior space of the nose, bounded by the oral cavity and nasal bones. Bones and cartilage maintain unobstructed passages; divided into left and right halves by the nasal septum.
- Contains:
- Paranasal sinuses: Lined with mucous membranes; vibrate to permit singing/speech.
- Nasal conchae: Swirl inhaled air.
- Olfactory epithelium: Ciliated (without goblet cells); contains sensory receptors for smells.
- Contains:
- Pharynx: Skeletal muscle tube lined with mucous membrane. Starts at internal nares and continues to the cricoid cartilage. Subdivided into:
- Nasopharynx: Superior; lined with ciliated pseudostratified columnar epithelium; sweeps mucus into the pharynx.
- Oropharynx: Intermediate; common passage for air and food; lined with non-keratinized stratified squamous epithelium; contains tonsils (trap pathogens).
- Laryngopharynx: Inferior; similar structure to oropharynx.
- Larynx: Tube comprising nine rings of cartilage.
- Thyroid cartilage: Hyaline cartilage forming the anterior surface of the larynx; Adam's apple (larger in males).
- Epiglottis: Flap of elastic cartilage; covers entrance during swallowing.
- Cricoid cartilage: Ring of hyaline cartilage at the inferior portion of the larynx; important for tracheotomies.
- Vocal folds (true vocal cords): Made of non-keratinized stratified squamous epithelium, form elastic ligaments stretch across the larynx; air vibrates them to make sounds. Muscles on cartilages change voice pitch.
- Vestibular folds (false vocal cords): Come together.
- Trachea: 2.5 cm wide x 12 cm long tube, 16–20 rings of hyaline cartilage; connected by dense CT; keeps trachea patent (open); anterior to the esophagus; lined with ciliated pseudostratified epithelium.
- Bronchi: Trachea splits into right and left bronchi (carina is ridge at branchpoint, sensitive to trigger cough; branch into lungs as narrowing vessels (bronchial tree); end in terminal bronchioles.
- Lungs: Wrapped in pleural membrane (two serous membranes with pleural fluid for reduced friction and surface tension); separated by the mediastinum. Extend from clavicles to diaphragm; Anterior/Posterior costal surfaces to ribs; base inferiorly (concave shape conforming to diaphragm); apex superiorly. Mediastinal surfaces including hilum (passage for bronchi, vessels, nerves, lymphatic vessels) and cardiac notch (space for heart). Fissures divide lungs into lobes (oblique fissure separates superior and inferior lobes, horizontal fissure borders middle lobe of right lung only); lobules are smaller compartments containing bronchioles, arterioles, venules, lymphatic vessels, and elastic connective tissue. Respiratory bronchioles branch into alveolar ducts, which terminate in alveolar sacs (clusters of alveoli); made of two cell types—Type I (simple squamous epithelium, thinness for gas diffusion) and Type II (nonciliated cuboidal epithelium at septa between alveoli, secrete surfactant [phospholipids + lipoproteins] preventing sticking and patrolled by macrophages). Respiratory membrane: alveoli + associated capillaries, very thin (~0.5 µm).
- Blood supply to the lungs:
- Pulmonary arteries: Bring deoxygenated blood from right ventricle; constrict in response to hypoxia (ventilation-perfusion coupling ensuring only healthy tissues are maximally perfused).
- Bronchial arteries: Branch from the aorta, deliver oxygenated blood to lung tissue.
Gas Exchange and Ventilation
- Pulmonary ventilation: Inhalation and exhalation; regulated by pressure changes in thoracic cavity; requires contraction of respiratory muscles; gases move from high to low partial pressures.
- Inhalation (inspiration): Lowers pressure in lungs below atmospheric pressure; diaphragm contracts and depresses; external intercostals contract, elevates ribs; increasing thoracic volume. Intrapleural pressure is negative (lower than atmospheric), keeps pleural membrane suctioned to thoracic cavity wall.
- Exhalation: Passive process; respiratory muscles relax; elastic recoil of lung tissues increase pressure inside lungs, gases diffuse out.
- Factors affecting pulmonary ventilation: Surfactant is crucial. Compliance is the distensibility of elastic tissues; high compliance = low effort. Resistance: airway diameter, smooth muscle, obstruction/collapse.
- Lung volumes and capacities are specific measures of air and sums of volumes. Measured with spirometers.
- Principles of gas exchange: Passive diffusion from high to low partial pressure; solubility of gas also matters (CO2 is more soluble in water than oxygen).
- External respiration: Gas exchange between alveoli and blood across pulmonary capillaries.
- Internal respiration: Gas exchange between blood and tissues. Tissue cells produce CO2, resulting in higher PCO2 outside systemic capillaries. Oxygen from blood moves into tissues.
Oxygen Transport
- Most oxygen is transported bound to hemoglobin (Hb).
- Hb binds oxygen reversibly; increased PO2 favors Hb-O2 formation. Hemoglobin saturation is the average saturation of hemoglobin.
- Factors affecting Hb saturation: PO2 (high PO2 in alveoli, low in working muscle), Hb affinity for oxygen (affected by acidity, PCO2, temperature, glycolysis intermediates, and hemoglobin type). High PCO2, acidic blood, increased temperature decreasing Hb affinity. Hb-F (fetal) binds more oxygen than adult Hb (Hb-A) because it doesn't bind BPG.
Carbon Dioxide Transport
- Carbon dioxide is transported in three main forms: Dissolved in blood plasma (7%), bound to proteins (23% - carbaminohemoglobin), and as bicarbonate (70%). Chloride shift maintains electrical balance.
Regulation of Breathing
- Respiratory center: Cluster of neurons in the brain (medulla oblongata and pons).
- Medullary respiratory group:
- Dorsal respiratory group (DRG): Normal breathing.
- Ventral respiratory group (VRG): Forceful breathing.
- Pontine respiratory group: Influences normal breathing.
- Medullary respiratory group:
- Cortical influences on breathing: Permits voluntary control.
- Chemoreceptors:
- Central: Located in medulla oblongata; sense changes in PCO2 and/or H+ in cerebrospinal fluid (CSF).
- Peripheral: Located in aortic and carotid bodies; sense changes in blood pH.
- Factors affecting respiration: Hyperventilation (low blood pH, high PCO2; response is to increase breathing), hypocapnia (low PCO2, chemoreceptors don’t signal), inflation reflex.
- Other influences on breathing: Emotions, temperature, pain, airway irritation, blood pressure.
Exercise and the Respiratory System
- Exercise increases pulmonary perfusion and ventilation.
Homeostatic Imbalances
- Tobacco smoking causes COPD, emphysema.
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Description
Explore the fascinating process of respiration and the anatomy of the human respiratory system. This quiz covers the stages of gas exchange, the functions of the respiratory system, and the various respiratory structures. Test your knowledge on external and internal respiration as well as the importance of oxygen for cellular processes.
