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What is the primary function of the pulmonary ventilation process?
What is the primary function of the pulmonary ventilation process?
Which of the following is part of the lower respiratory system?
Which of the following is part of the lower respiratory system?
What role does the conducting zone play in the respiratory system?
What role does the conducting zone play in the respiratory system?
What is one of the functions of the respiratory system related to waste management?
What is one of the functions of the respiratory system related to waste management?
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What is the primary purpose of external respiration?
What is the primary purpose of external respiration?
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What is the primary physiological effect of hyperventilation?
What is the primary physiological effect of hyperventilation?
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What can result from hyperventilation?
What can result from hyperventilation?
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Which type of receptors sense lung stretching and help regulate breathing?
Which type of receptors sense lung stretching and help regulate breathing?
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What effect do emotions have on the respiratory center?
What effect do emotions have on the respiratory center?
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How does increased blood pressure affect respiration rate?
How does increased blood pressure affect respiration rate?
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What is the role of pulmonary perfusion during exercise?
What is the role of pulmonary perfusion during exercise?
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What is a consequence of chronic obstructive pulmonary disease (COPD) due to tobacco smoking?
What is a consequence of chronic obstructive pulmonary disease (COPD) due to tobacco smoking?
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What is the main effect of hypoxia on the body?
What is the main effect of hypoxia on the body?
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What is the function of pleural fluid in the lungs?
What is the function of pleural fluid in the lungs?
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What is the inferior portion of the lungs referred to as?
What is the inferior portion of the lungs referred to as?
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Which structure permits the passage of bronchi and blood vessels into the lungs?
Which structure permits the passage of bronchi and blood vessels into the lungs?
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What is the role of type II alveolar cells in the alveoli?
What is the role of type II alveolar cells in the alveoli?
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Which arteries supply oxygenated blood to the muscular tissue of the lungs?
Which arteries supply oxygenated blood to the muscular tissue of the lungs?
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What does the term 'patency' refer to in the context of airways?
What does the term 'patency' refer to in the context of airways?
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Which of the following describes Boyle's Law?
Which of the following describes Boyle's Law?
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What separates the superior and inferior lobes of the lungs?
What separates the superior and inferior lobes of the lungs?
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Which cells in the alveoli allow for efficient gas diffusion due to their thin structure?
Which cells in the alveoli allow for efficient gas diffusion due to their thin structure?
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What happens to pulmonary arteries in response to hypoxia?
What happens to pulmonary arteries in response to hypoxia?
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What are lobar bronchi named after?
What are lobar bronchi named after?
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What is the primary role of the respiratory membrane?
What is the primary role of the respiratory membrane?
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How are lobules defined in the lung structure?
How are lobules defined in the lung structure?
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What must occur for inhalation to take place?
What must occur for inhalation to take place?
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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 structure covers the entrance to the larynx during swallowing?
Which structure covers the entrance to the larynx during swallowing?
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What type of epithelium lines the oropharynx?
What type of epithelium lines the oropharynx?
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Which of the following is a major function of the true vocal cords?
Which of the following is a major function of the true vocal cords?
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What maintains the patency of the trachea?
What maintains the patency of the trachea?
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The cricoid cartilage is a landmark for which medical procedure?
The cricoid cartilage is a landmark for which medical procedure?
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Where does the trachea bifurcate into the right and left bronchi?
Where does the trachea bifurcate into the right and left bronchi?
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What type of epithelium is found in the nasal cavity?
What type of epithelium is found in the nasal cavity?
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What is the role of the olfactory epithelium in the nasal cavity?
What is the role of the olfactory epithelium in the nasal cavity?
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Which part of the pharynx is lined with ciliated pseudostratified columnar epithelium?
Which part of the pharynx is lined with ciliated pseudostratified columnar epithelium?
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What is primarily responsible for 75% of inhaled air?
What is primarily responsible for 75% of inhaled air?
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What happens to intrapleural pressure during inhalation?
What happens to intrapleural pressure during inhalation?
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What type of process is exhalation under normal circumstances?
What type of process is exhalation under normal circumstances?
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Which factor does NOT affect pulmonary ventilation?
Which factor does NOT affect pulmonary ventilation?
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What defines compliance in the context of respiratory physiology?
What defines compliance in the context of respiratory physiology?
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How does the diameter of airways affect airflow resistance?
How does the diameter of airways affect airflow resistance?
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What is the function of surfactant in the lungs?
What is the function of surfactant in the lungs?
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In which situation would the alveoli's partial pressure of oxygen (PO2) be lower than normal?
In which situation would the alveoli's partial pressure of oxygen (PO2) be lower than normal?
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Which component of gas exchange allows for higher rates of diffusion?
Which component of gas exchange allows for higher rates of diffusion?
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How is oxygen primarily transported in the blood?
How is oxygen primarily transported in the blood?
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What occurs to carbon dioxide levels in the blood during tissue respiration?
What occurs to carbon dioxide levels in the blood during tissue respiration?
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What is the primary reason that oxygen is transported faster than carbon dioxide is eliminated from the body?
What is the primary reason that oxygen is transported faster than carbon dioxide is eliminated from the body?
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What physiological change occurs as a result of elastic recoil in the lungs?
What physiological change occurs as a result of elastic recoil in the lungs?
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What is the correct percentage saturation of hemoglobin when each molecule has, on average, two O2 atoms bound?
What is the correct percentage saturation of hemoglobin when each molecule has, on average, 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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How is the majority of carbon dioxide transported in the blood?
How is the majority of carbon dioxide transported in the blood?
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What occurs when the partial pressure of oxygen (PO2) increases?
What occurs when the partial pressure of oxygen (PO2) increases?
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What is the role of chloride ions during gas exchange at the systemic capillaries?
What is the role of chloride ions during gas exchange at the systemic capillaries?
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Which type of hemoglobin binds oxygen with greater affinity during fetal development?
Which type of hemoglobin binds oxygen with greater affinity during fetal development?
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What physiological condition decreases hemoglobin's affinity for oxygen?
What physiological condition decreases hemoglobin's affinity for oxygen?
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What is the main functional role of the dorsal respiratory group (DRG)?
What is the main functional role of the dorsal respiratory group (DRG)?
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What are central chemoreceptors primarily sensitive to?
What are central chemoreceptors primarily sensitive to?
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During vigorous exercise, how does the pH of blood typically change?
During vigorous exercise, how does the pH of blood typically change?
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What is produced when carbonic acid dissociates in the blood?
What is produced when carbonic acid dissociates in the blood?
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What primarily triggers the return to normal breathing after breath-holding?
What primarily triggers the return to normal breathing after breath-holding?
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Which process occurs during the reverse chloride shift at the pulmonary capillaries?
Which process occurs during the reverse chloride shift at the pulmonary capillaries?
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In which area of the brain is the primary respiratory center located?
In which area of the brain is the primary respiratory center located?
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Study Notes
Introduction to Respiration
- Respiration is the process of acquiring oxygen and eliminating carbon dioxide.
- Three steps in the human body:
- Pulmonary ventilation: Gas exchange between the atmosphere & lungs.
- 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 and smell, filters inhaled air, and excretes wastes during exhalation.
- Oto(rhino)laryngology is the study of the respiratory system.
- Cells need oxygen for aerobic cellular respiration.
Anatomy of the Respiratory System
- Structurally, the respiratory system is divided into:
- Upper respiratory system: Nose, nasal cavity, pharynx, and associated structures.
- Lower respiratory system: Larynx, trachea, bronchi, and lungs.
- Functionally, the respiratory system is divided into:
- Conducting zone: Directs air, filters, warms, and humidifies it.
- Respiratory zone: Site of gas exchange (respiratory bronchioles, alveolar ducts, alveolar sacs).
Upper Respiratory System
- The nose: Made of bone, cartilage, and connective tissue. Air enters via external nares (nostrils).
- The nasal cavity: Interior and anterior space of the nose. Separated into left and right halves by the nasal septum. Contains:
- Paranasal sinuses: Lined with mucous membranes, vibrate for sound.
- Nasal conchae: Swirl inhaled air.
- Olfactory epithelium: Contains sensory receptors for smell (no goblet cells).
- Pharynx: Tube of skeletal muscle, lined with mucous membrane, subdivided into:
- Nasopharynx (superior): Lined with ciliated pseudostratified columnar epithelium, sweeps mucus to the pharynx.
- Oropharynx (intermediate): Common passageway for air and food, contains tonsils, lined with non-keratinized stratified squamous epithelium.
- Laryngopharynx (inferior): Similar structure to oropharynx.
- The larynx: Tube comprised of nine rings of cartilage.
- Thyroid cartilage ("Adam's apple"): Hyaline cartilage, larger in males.
- Epiglottis: Flap of elastic cartilage, covers the larynx opening during swallowing.
- Cricoid cartilage: Ring of hyaline cartilage at the inferior portion of the larynx, landmark for tracheotomies.
- Vocal folds (true vocal cords): Made of non-keratinized stratified squamous epithelium, vibrate to produce sound.
- Vestibular folds (false vocal cords): Come together during breath holding.
The Trachea
- 2.5 cm wide x 12 cm long tube.
- 16–20 rings of hyaline cartilage that keep the trachea patent (open).
- Anterior to the esophagus; lined with ciliated pseudostratified columnar epithelium.
The Bronchi
- Trachea splits into the right and left bronchi.
- Carina: Ridge at the branchpoint.
- Bronchial tree: Narrowing vessels branching into lungs.
- Terminal bronchioles: End in lung sacs.
The Lungs
- Wrapped in pleural membrane (2 serous membranes).
- Pleural fluid reduces friction and provides surface tension.
- Separated by the mediastinum.
- Extend from clavicles to diaphragm.
- Mediastinal surfaces include:
- Hilum: Permits passage of bronchi, blood vessels, nerves, and lymphatic vessels.
- Cardiac notch: Space for the heart (decreases size of left lung).
- Fissures divide the lungs into lobes:
- Oblique fissure: Separates the superior and inferior lobes.
- Horizontal fissure: Separates the middle and superior lobes (only in the right lung).
- Lobes contain bronchi named after the lobes: superior, middle (right lung only), inferior lobar bronchi.
- Each lobar bronchus branches into segmental bronchi: supporting one bronchopulmonary segment (13 in right; 8 in left).
- Bronchopulmonary segments are further divided into lobules:
- With a terminal bronchiole, arteriole, venule, and lymphatic vessel, all wrapped in elastic connective tissue.
- Respiratory bronchioles are microscopic bronchial branches, lined with simple cuboidal epithelium. Branch into alveolar ducts, lined with simple squamous epithelium. Alveloi where pulmonary & external respiration occur.
Alveoli
- Alveoli: air sacs where gas exchange occurs, extensive surface area.
- Type I alveolar cells: Simple squamous epithelium, thinness facilitates gas diffusion.
- Type II alveolar cells: Nonciliated cuboidal epithelium, secrete surfactant (phospholipids + lipoproteins) to prevent sticking.
- Respiratory membrane: Alveoli + associated capillaries (0.5 µm thick): alveolar wall, epithelial basement membrane, capillary basement membrane, capillary endothelium.
Blood Supply to Lungs
- Pulmonary arteries: Bring deoxygenated blood to be oxygenated.
- Bronchial arteries: Branch from aorta, deliver oxygenated blood to lung tissue.
Gas Exchange and Ventilation
- Pulmonary ventilation involves inhalation and exhalation, leading to gas exchange at the alveoli. Regulated by pressure changes in the thoracic cavity.
- Mechanics of inhalation:
- Atmospheric pressure > intrapulmonary pressure.
- Thoracic cavity volume increase → intrapulmonary pressure decreases → air moves into lungs.
- Boyle's Law: Pressure is inversely proportional to volume.
- Diaphragm contracts → depresses → decreases intrapulmonary pressure.
- Intercostal muscles contract → elevate ribs → further increase thoracic volume.
- Intrapleural pressure: Negative pressure (lower than atmospheric), keeps pleural membrane attached to thoracic wall, enabling expansion of lungs with cavity wall.
- Mechanics of exhalation:
- Passive process. Respiratory muscles relax → thoracic cavity volume decreases → intrapulmonary pressure increases → air moves out of lungs.
- Factors affecting pulmonary ventilation:
- Surfactant: Prevents alveoli collapse.
- Compliance: Distensibility of elastic tissues in lungs & chest wall. Low compliance = difficulty breathing.
- Resistance: Caused by airway diameter & airway obstruction.
Lung Volumes and Capacities
- Lung volumes: Specific measures of air, measured using a spirometer (output is a spirogram).
- Lung capacities: Sum of volumes.
Principles of Gas Exchange
- Gases move from high to low partial pressure.
- Carbon dioxide is more soluble than oxygen.
- External respiration: Gas exchange between alveoli & blood.
- Internal respiration: Gas exchange between blood and body tissues.
Factors Affecting Respiration
- Partial pressure gradient.
- Surface area.
- Diffusion distance.
- Molecular weight and solubility.
Oxygen Transport
- 98.5% of oxygen is transported attached to hemoglobin (Hb) within erythrocytes, the rest is dissolved in blood plasma.
- Hb binds oxygen reversibly. Increased PO2 favors Hb-O2 formation, leading to higher saturation.
- Factors influencing Hb saturation:
- PO2
- Blood acidity ([H+]).
- PCO2
- Temperature
- Intermediate products of glycolysis
- Types of hemoglobin
Carbon Dioxide Transport
- Carbon dioxide transport: Dissolved in blood plasma, bound to proteins (carbamino compounds), or as bicarbonate.
- Chloride shift: Ensures electrical balance in erythrocytes. Exchange of chloride for bicarbonate maintains equilibrium in red blood cells.
Regulation of Breathing
- Respiratory center: Cluster of neurons in medulla oblongata & pons, regulate respiratory muscles.
- Medullary respiratory group (DRG & VRG): Controls normal & forceful breathing.
- Pontine respiratory group: Influences normal breathing by affecting DRG.
- Cortical influences: Conscious control of breathing.
- Chemoreceptors: Sense chemical changes in blood.
- Central chemoreceptors: Located near medulla, sense PCO2 and H+ in CSF.
- Peripheral chemoreceptors: In aortic and carotid bodies, sense PCO2 and H+.
- Inflation reflex: Prevents overinflation of lungs.
- Other Influences: Emotions, temperature, pain, airway irritation, and blood pressure.
- Exercise and the respiratory system: Increased pulmonary perfusion matched by ventilation. Chemoreceptors trigger increased rate/depth of breathing.
Homeostatic Imbalances
- Smoking can lead to COPD (increased mucus, impaired ciliary function, emphysema, decreased alveolar surface area).
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Description
This quiz covers the fundamental concepts of respiration and the anatomy of the respiratory system. It explains the process of gas exchange, the functions of the respiratory system, and the anatomical divisions of the system. Test your knowledge on pulmonary ventilation, external and internal respiration, and more.
