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What is the primary function of the respiratory system?
What is the primary function of the respiratory system?
Which of the following best describes external respiration?
Which of the following best describes external respiration?
What is the role of the conducting zone in the respiratory system?
What is the role of the conducting zone in the respiratory system?
What structures are included in the upper respiratory system?
What structures are included in the upper respiratory system?
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Why do cells require oxygen?
Why do cells require oxygen?
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What is the primary function of the nasal conchae?
What is the primary function of the nasal conchae?
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Which part of the pharynx is lined with non-keratinized stratified squamous epithelium?
Which part of the pharynx is lined with non-keratinized stratified squamous epithelium?
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What structure covers the entrance of the larynx during swallowing?
What structure covers the entrance of the larynx during swallowing?
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Which component of the larynx is responsible for voice production?
Which component of the larynx is responsible for voice production?
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What is the function of the carina in the bronchial tree?
What is the function of the carina in the bronchial tree?
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What type of epithelial lining is found in the trachea?
What type of epithelial lining is found in the trachea?
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Which cartilage is known as the 'Adam’s apple'?
Which cartilage is known as the 'Adam’s apple'?
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What is the role of tonsils in the oropharynx?
What is the role of tonsils in the oropharynx?
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What ensures the trachea remains open?
What ensures the trachea remains open?
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What is the primary role of the olfactory epithelium?
What is the primary role of the olfactory epithelium?
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What physiological response occurs due to low blood pH?
What physiological response occurs due to low blood pH?
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What is the result of hyperventilation on PCO2 levels in the blood?
What is the result of hyperventilation on PCO2 levels in the blood?
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Which receptors sense lung overinflation during vigorous exercise?
Which receptors sense lung overinflation during vigorous exercise?
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What effect does increased blood pressure have on respiration rate?
What effect does increased blood pressure have on respiration rate?
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What leads to the impairment of ciliary function due to tobacco smoking?
What leads to the impairment of ciliary function due to tobacco smoking?
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What condition can result from insufficient oxygen due to hyperventilation?
What condition can result from insufficient oxygen due to hyperventilation?
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What drives the increase in pulmonary perfusion during exercise?
What drives the increase in pulmonary perfusion during exercise?
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What may happen to the DRG when PCO2 in blood drops below 40 mm Hg?
What may happen to the DRG when PCO2 in blood drops below 40 mm Hg?
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What is the primary function of pleural fluid in the lungs?
What is the primary function of pleural fluid in the lungs?
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Which structure separates the lungs from each other?
Which structure separates the lungs from each other?
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What is the name of the inferior portion of the lungs?
What is the name of the inferior portion of the lungs?
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What type of fissure separates the superior and inferior lobes of the lungs?
What type of fissure separates the superior and inferior lobes of the lungs?
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Which structure permits passage for bronchi, blood vessels, nerves, and lymphatic vessels into the lungs?
Which structure permits passage for bronchi, blood vessels, nerves, and lymphatic vessels into the lungs?
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What are the microscopic bronchial branches that lead to alveolar ducts called?
What are the microscopic bronchial branches that lead to alveolar ducts called?
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Which type of cells in the alveoli is primarily involved in gas diffusion?
Which type of cells in the alveoli is primarily involved in gas diffusion?
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What condition can compromise airway patency?
What condition can compromise airway patency?
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What relationship does Boyle’s Law describe in the context of respiration?
What relationship does Boyle’s Law describe in the context of respiration?
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What is the purpose of the pulmonary arteries?
What is the purpose of the pulmonary arteries?
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What is the alveolar ducts' primary structural feature?
What is the alveolar ducts' primary structural feature?
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What prevents the walls of the alveoli from sticking together?
What prevents the walls of the alveoli from sticking together?
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Which segment of the respiratory system directly contacts blood for gas exchange?
Which segment of the respiratory system directly contacts blood for gas exchange?
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Which factors are involved in ventilation-perfusion coupling?
Which factors are involved in ventilation-perfusion coupling?
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What happens when the diaphragm contracts?
What happens when the diaphragm contracts?
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What is the primary role of pleural pressure during inhalation?
What is the primary role of pleural pressure during inhalation?
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Which muscles contract to assist the diaphragm during inhalation?
Which muscles contract to assist the diaphragm during inhalation?
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How much does the diaphragm depress during normal inhalation?
How much does the diaphragm depress during normal inhalation?
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What factor is NOT associated with low lung compliance?
What factor is NOT associated with low lung compliance?
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What is the primary mechanism for carbon dioxide transport in the blood?
What is the primary mechanism for carbon dioxide transport in the blood?
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What primarily causes the movement of gases during internal respiration?
What primarily causes the movement of gases during internal respiration?
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What defines lung volume?
What defines lung volume?
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Which condition is associated with insufficient surfactant?
Which condition is associated with insufficient surfactant?
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What happens during passive exhalation?
What happens during passive exhalation?
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What is the effect of airway diameter on airflow resistance?
What is the effect of airway diameter on airflow resistance?
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How does altitude sickness affect respiration?
How does altitude sickness affect respiration?
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What role does hemoglobin play in oxygen transport?
What role does hemoglobin play in oxygen transport?
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In what way does the solubility of carbon dioxide compare to oxygen?
In what way does the solubility of carbon dioxide compare to oxygen?
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What is the percent saturation of hemoglobin when each Hb on average has two O2 atoms bound?
What is the percent saturation of hemoglobin when each Hb on average has two O2 atoms bound?
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Which factor does NOT affect the affinity of hemoglobin for oxygen?
Which factor does NOT affect the affinity of hemoglobin for oxygen?
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What happens to hemoglobin affinity for oxygen as blood pH decreases?
What happens to hemoglobin affinity for oxygen as blood pH decreases?
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How is most carbon dioxide transported in the blood?
How is most carbon dioxide transported in the blood?
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What does the chloride shift help maintain in erythrocytes?
What does the chloride shift help maintain in erythrocytes?
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What is a primary role of the dorsal respiratory group (DRG) in the medullary respiratory centre?
What is a primary role of the dorsal respiratory group (DRG) in the medullary respiratory centre?
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Which component predominantly influences the respiratory rate after holding one's breath?
Which component predominantly influences the respiratory rate after holding one's breath?
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The affinity of fetal hemoglobin (Hb-F) for oxygen compared to adult hemoglobin (Hb-A) is:
The affinity of fetal hemoglobin (Hb-F) for oxygen compared to adult hemoglobin (Hb-A) is:
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What is the role of 2,3-bisphosphoglycerate (BPG) in hemoglobin function?
What is the role of 2,3-bisphosphoglycerate (BPG) in hemoglobin function?
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At a PO2 of 20 mm Hg, the saturation of hemoglobin in working skeletal muscle is approximately:
At a PO2 of 20 mm Hg, the saturation of hemoglobin in working skeletal muscle is approximately:
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What occurs during the reverse chloride shift at pulmonary capillaries?
What occurs during the reverse chloride shift at pulmonary capillaries?
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Which term describes the binding of hemoglobin with carbon dioxide to form a compound?
Which term describes the binding of hemoglobin with carbon dioxide to form a compound?
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What is the brain's central structure responsible for regulating the respiratory muscles?
What is the brain's central structure responsible for regulating the respiratory muscles?
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During which physiological condition does the affinity of hemoglobin for oxygen increase?
During which physiological condition does the affinity of hemoglobin for oxygen increase?
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Study Notes
Introduction to Respiration
- Respiration is the process of acquiring oxygen and eliminating carbon dioxide.
- The human respiratory system involves three key steps:
- Pulmonary ventilation: Gas exchange between the atmosphere and lungs.
- External respiration: Gas exchange between lung tissues and blood.
- Internal respiration: Gas exchange between blood and body tissues.
- Functions of the respiratory system include:
- Gas exchange.
- Regulating blood pH.
- Enabling vocal sounds and the sense of smell, filtering inhaled air, and excreting wastes during exhalation.
- Oto(rhino)laryngology is the study of the respiratory system.
- Cells require oxygen for aerobic cellular respiration.
Anatomy of the Respiratory System
- The respiratory system is structurally divided into:
- Upper respiratory system: Nose, nasal cavity, pharynx, and associated structures.
- Lower respiratory system: Larynx, trachea, bronchi, and lungs.
- Functionally, the system is divided into:
- Conducting zone: Directs air toward the respiratory zone, filtering, warming, and humidifying air.
- Respiratory zone: Site of gas exchange, including respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.
Upper Respiratory System
- Nose: Made of bone, cartilage, and connective tissues. Air enters through external nares (nostrils).
-
Nasal Cavity: Interior space of the nose. Bounded by the oral cavity and nasal bones. Maintained unobstructed by bone and cartilage. Divided by the nasal septum. Contains:
- Paranasal sinuses: Lined with mucous membranes, important for voice resonance.
- Nasal conchae: Swirl inhaled air.
- Olfactory epithelium: Contains sensory receptors for smell; ciliated, but no goblet cells.
-
Pharynx: Tube of skeletal muscle. Starts at the internal nares and continues to the cricoid cartilage. Three sections:
- Nasopharynx: Lined with ciliated pseudostratified columnar epithelium, sweeping mucus into the pharynx.
- Oropharynx: Common passage for air and food; lined with non-keratinized stratified squamous epithelium, contains tonsils (trap pathogens).
- Laryngopharynx: Similar to oropharynx but inferior.
Larynx
- Tube of nine cartilages.
- Thyroid cartilage: Hyaline cartilage; prominent in males (Adam's apple).
- Epiglottis: Flap of elastic cartilage covering the larynx during swallowing.
- Cricoid cartilage: Hyaline cartilage ring; landmark for tracheotomies.
- Vocal folds (true vocal cords): Non-keratinized stratified squamous epithelium; form elastic ligaments. Vibrate for sound production. Muscle tension controls pitch.
- Vestibular folds (false vocal cords): Come together when holding breath.
Trachea
- 2.5 cm wide x 12 cm long tube.
- 16-20 hyaline cartilage rings connected by dense connective tissue. This maintains patency.
- Anterior to the esophagus. Lined with ciliated pseudostratified epithelium.
Bronchi
- Trachea splits into right and left bronchi.
- Carina: Ridge at branch point, sensitive to trigger cough reflex.
- Bronchial tree: Narrowing vessels branching into lungs, ending in terminal bronchioles.
- Mucous membrane structure changes throughout the bronchial tree. Supporting cartilage and smooth muscle proportions also change.
Lungs
- Wrapped in pleural membrane (two serous membranes separated by a pleural cavity). Fluid reduces friction and creates surface tension.
- Extend from clavicles to diaphragm, bordering the costal surfaces of ribs. Separated by the mediastinum.
-
Base (inferior portion) and apex (superior portion). Medial surfaces (mediastinal surfaces) include:
- Hilum: Passage for bronchi, blood vessels, nerves, and lymphatics.
- Cardiac notch: Space for the heart, reducing left lung size.
-
Fissures: Divide lungs into lobes.
- Oblique fissure: Separates superior and inferior lobes in both lungs.
- Horizontal fissure: Separates middle from superior lobe in right lung only.
- Lobar bronchi: Named after the lobes; branch into segmental bronchi.
- Bronchopulmonary segments: Each supplied by a segmental bronchus, 13 on the right and 8 on the left. Can be removed surgically.
- Lobules: Smaller compartments of a bronchopulmonary segment, each containing a branch of a terminal bronchiole, arteriole/venule, and lymphatic vessel, all wrapped in elastic connective tissue.
- Respiratory bronchioles: Microscopic branches of bronchi, lined with simple cuboidal epithelium. Branch into alveolar ducts (lined with simple squamous epithelium).
-
Alveoli: Air sacs for gas exchange.
- Type I alveolar cells: Simple squamous epithelium facilitating gas diffusion.
- Type II alveolar cells: Nonciliated cuboidal epithelium; secrete surfactant (to prevent alveolar collapse)
- Alveolar macrophages: Patrol alveoli.
- Respiratory membrane: Alveoli and associated capillaries; very thin (~0.5 µm), facilitating rapid gas diffusion. Contains alveolar walls, epithelial basement membrane, capillary basement membrane and capillary endothelium.
Blood Supply to the Lungs
- Pulmonary arteries: Bring deoxygenated blood to lungs for oxygenation. constrict if oxygen levels are low
- Bronchial arteries: Branch from the aorta; deliver oxygenated blood to lung tissue.
Gas Exchange and Ventilation
- Pulmonary ventilation: Inhalation and exhalation, leads to gas exchange in alveoli. Controlled by pressure changes in the thorax.
- Inhalation (inspiration): Lungs expand to lower pressure (below atmospheric pressure) and air flows in. Achieved by diaphragm contraction and external intercostal muscle contraction.
- Exhalation (expiration): Passive process. Respiratory muscles relax resulting in elastic recoil and increase in pressure in the lungs.
- Factors affecting pulmonary ventilation include surfactant, compliance (distensibility of lung tissue) and resistance (airway diameter and obstruction).
- Lung volumes and capacities are measured to assess respiratory function (spirometry).
Principles of Gas Exchange
- Passive diffusion of gases from high to low partial pressures.
- Solubility of CO2 is significantly higher than oxygen in water; this greatly affects the movement of gasses between lungs, blood and body tissues.
- External respiration occurs between alveoli and blood.
- Internal respiration occurs between blood and body tissues.
Factors Affecting Respiration
- Partial pressure gradients; surface area for gas exchange; diffusion distance; molecular weight and solubility.
- Other factors affecting respiration include blood pH, PCO2, temperature, BPG levels, hemoglobin type.
Oxygen Transport
- Hemoglobin (Hb) carries most oxygen in the blood (98.5%).
- Oxygen binds to the iron (Fe) in the heme groups of Hb, reversibly.
- Factors affecting Hb saturation include PO2, blood acidity, PCO2, temperature, BPG levels, hemoglobin type (fetus vs adult).
Carbon Dioxide Transport
- Carbon dioxide is transported in blood in three forms: dissolved CO2, carbamino compounds, and bicarbonate.
- Chloride shift maintains electrical balance during CO2 transport.
Regulation of Breathing
- Respiratory center in the medulla oblongata and pons controls respiratory muscles.
- Medullary respiratory group (DRG and VRG): controls normal and forceful breathing.
- Pontine respiratory group influences normal breathing through the DRG.
- Cortical influences allow voluntary control of breathing.
- Chemoreceptors (central and peripheral) detect changes in PCO2 and/or H+ levels to regulate breathing rate and depth.
- Hypoxia and hyperventilation are responses to changes in blood chemistry and are controlled via the inflation reflex.
Other Influences on Breathing
- Emotions; temperature; pain; airways irritation; blood pressure affect breathing. Exercise increases ventilation and pulmonary perfusion.
Homeostatic Imbalances
- Smoking can lead to COPD (including impaired ciliary function and emphysema).
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Description
This quiz covers the basics of respiration and the anatomy of the respiratory system. Key concepts include pulmonary ventilation, gas exchange, and the structure of the upper and lower respiratory systems. Test your understanding of how oxygen is acquired and carbon dioxide is eliminated in the human body.
