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Questions and Answers
What is the primary function of the nasopharynx?
What is the primary function of the nasopharynx?
Which region of the pharynx is lined with stratified squamous epithelium?
Which region of the pharynx is lined with stratified squamous epithelium?
What structure in the larynx is responsible for the production of sound?
What structure in the larynx is responsible for the production of sound?
Which of the following cartilages is the largest in the larynx?
Which of the following cartilages is the largest in the larynx?
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What connects the pharynx to the middle ear?
What connects the pharynx to the middle ear?
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What causes air to flow during pulmonary ventilation?
What causes air to flow during pulmonary ventilation?
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According to Boyle's Law, what is the relationship between the volume of a gas and its pressure?
According to Boyle's Law, what is the relationship between the volume of a gas and its pressure?
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During inhalation, which muscle is primarily responsible for the initial contraction?
During inhalation, which muscle is primarily responsible for the initial contraction?
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What occurs to the pressure in the lungs during inhalation?
What occurs to the pressure in the lungs during inhalation?
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What happens to the diaphragm during exhalation?
What happens to the diaphragm during exhalation?
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What is the primary role of type II alveolar cells?
What is the primary role of type II alveolar cells?
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Which characteristic is NOT true of terminal bronchioles?
Which characteristic is NOT true of terminal bronchioles?
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What constitutes the respiratory membrane?
What constitutes the respiratory membrane?
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What is the primary function of the lungs in relation to the thoracic cavity?
What is the primary function of the lungs in relation to the thoracic cavity?
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What initiates blood flow redistribution in the lungs due to hypoxia?
What initiates blood flow redistribution in the lungs due to hypoxia?
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What are the primary components of the upper respiratory system?
What are the primary components of the upper respiratory system?
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Where does deoxygenated blood for alveoli come from?
Where does deoxygenated blood for alveoli come from?
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How many alveoli are typically found in human lungs?
How many alveoli are typically found in human lungs?
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Which of the following best describes the conducting zone of the respiratory system?
Which of the following best describes the conducting zone of the respiratory system?
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What is the primary function of the nasal cavity?
What is the primary function of the nasal cavity?
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Which part of the lung is primarily in contact with the ribs?
Which part of the lung is primarily in contact with the ribs?
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Which statement about the respiratory and cardiovascular systems is correct?
Which statement about the respiratory and cardiovascular systems is correct?
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What role do paranasal sinuses play in the respiratory system?
What role do paranasal sinuses play in the respiratory system?
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What component is included in the lower respiratory system?
What component is included in the lower respiratory system?
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Which process is NOT part of the respiration processes?
Which process is NOT part of the respiration processes?
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How do alveoli facilitate the exchange of gases?
How do alveoli facilitate the exchange of gases?
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Which best describes ventilation in the context of breathing?
Which best describes ventilation in the context of breathing?
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What is the primary function of the pharynx in the respiratory system?
What is the primary function of the pharynx in the respiratory system?
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What is the primary function of the neurons in the dorsal respiratory group (DRG)?
What is the primary function of the neurons in the dorsal respiratory group (DRG)?
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Which structure is identified as the respiratory rhythm generator?
Which structure is identified as the respiratory rhythm generator?
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How do the pontine respiratory group (PRG) neurons affect breathing?
How do the pontine respiratory group (PRG) neurons affect breathing?
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What role do central and peripheral chemoreceptors play in respiration?
What role do central and peripheral chemoreceptors play in respiration?
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What occurs during the inflation reflex?
What occurs during the inflation reflex?
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Which statement accurately describes exhalation?
Which statement accurately describes exhalation?
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What is typically true about the patients with COPD?
What is typically true about the patients with COPD?
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Which of the following correctly characterizes asthma?
Which of the following correctly characterizes asthma?
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What percentage of oxygen is carried by hemoglobin in the blood?
What percentage of oxygen is carried by hemoglobin in the blood?
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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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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 physiological change occurs during internal respiration?
What physiological change occurs during internal respiration?
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What contributes to the inhalation of air?
What contributes to the inhalation of air?
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Study Notes
Human Anatomy and Physiology: The Respiratory System
- Respiration is the exchange of gases between the atmosphere, blood, and cells.
- Four processes are involved: ventilation (breathing), external (pulmonary) respiration, transport of respiratory gases, and internal (tissue) respiration.
- The cardiovascular system helps transport gases as part of the respiratory system.
Learning Outcomes
- Describe the structure and function of each component of the respiratory system.
- List competing pressures involved in respiration, and describe how these gradients are created.
- Describe the mechanics of breathing and its relation to pressure changes.
- Explain how respiration can be assessed (Lung Volumes and Capacities) and the impact of disease upon respiratory function.
- Detail the transport of O₂ and CO₂ in the blood.
- Explain the neuronal mechanisms for controlling breathing, and the factors modulating these processes.
Components of the Respiratory System
- Structurally, the system is divided into upper and lower respiratory systems.
- Functionally, the system is divided into conducting and respiratory zones.
Structures of the Respiratory System
- Upper respiratory system comprises the nose, pharynx, larynx, and associated structures.
- Lower respiratory system includes the trachea, bronchi, and lungs.
The Respiratory System – Functional Zones
- Conducting zone: includes structures for air passage, no gas exchange (nose, nasal cavity, pharynx, larynx, trachea, bronchi, terminal bronchioles).
- Respiratory zone: site of gas exchange (respiratory bronchioles, alveolar ducts, alveoli). Thin-walled structures facilitate gas diffusion.
Anatomy of the Nose and Nasal Cavity
- The nose is the primary air passageway.
- Nostrils contain hair to filter large particles.
- Nasal cavity is the hollow space behind the nose, with two nasal cavities separated by the nasal septum.
- Paranasal sinuses are air-filled cavities, located within the skull, that lighten the skull and enhance voice resonance (maxillary, ethmoidal, frontal, sphenoidal sinuses).
Pharynx
- The pharynx is the throat, a common passageway for food and air, and houses the tonsils.
- Divided into three regions: nasopharynx (posterior to nasal cavity), oropharynx (posterior to oral cavity), and laryngopharynx (posterior to larynx).
- The nasopharynx is a passageway only for air.
Nasopharynx
- Continuous with the nasal cavity, it contains the pharyngeal tonsils and openings of the auditory tubes.
- It closes during swallowing to prevent food from entering the nasal cavity.
Oropharynx and Laryngopharynx
- Oropharynx: stratified squamous epithelium, extends from soft palate to epiglottis. Serves as a common pathway for food and air.
- Laryngopharynx: stratified squamous epithelium, extends from oropharynx, continues as esophagus.
Larynx
- The larynx (voice box) connects the pharynx and trachea.
- Made of muscles and cartilages (thyroid cartilage, cricoid cartilage, arytenoid cartilages, epiglottis, and cuneiform cartilages).
- Contains vocal folds for sound production. The vocal ligaments attach the arytenoid cartilage to the thyroid cartilage. Mucosal folds (true vocal cords) vibrate to produce sound; false vocal cords don't play a role in sound production. Glottis is the medial opening between true vocal cords.
- Functions: sound production, protecting lower respiratory tract (epiglottis during swallowing), passageway for air.
Trachea
- Trachea (windpipe): flexible tube connecting larynx to primary bronchi.
- Composed of three layers: mucosa (goblet cells and ciliated epithelium), submucosa (connective tissue and seromucous glands), adventitia (C-shaped cartilage rings).
Conducting Zone: Bronchi and Subdivisions (bronchial tree)
- Trachea branches into the right and left primary bronchi within the superior border of the fifth thoracic vertebra.
- Bronchi subdivide into smaller and smaller branches within lungs.
- Cartilage support decreases, smooth muscle increases as tubes get smaller.
- Epithelial cell types change as the tubes branch.
- Terminal bronchioles are the end of the conducting zone.
- Cuboidal epithelium, smooth muscle, lack cartilage.
Conducting and Respiratory Zones
- The conduction zone facilitates airflow to the respiratory zone.
- The respiratory zone is where gas exchange occurs.
Respiratory Zone: Bronchi and Subdivisions
- Respiratory bronchioles lead to alveolar ducts, then alveolar sacs and alveoli, approximately 300 million alveoli per lung make up gas exchange surface area.
Alveolar Cells
- Type I cells form the alveolar walls (simple squamous epithelium) and facilitate gas exchange through diffusion.
- Type II cells secrete surfactant, a mixture of lipids, and proteins to reduce surface tension and prevent alveoli from collapsing.
Respiratory Membrane
- The air-blood barrier consists of alveolar cells, alveolar basement membrane, capillary basement membrane, and capillary endothelium.
Lungs
- Occupy the thoracic cavity except the mediastinum.
- Encased and protected by the pleural membrane.
- The root (hilum) is the site of vascular and bronchial attachments.
- Costal surface contacts the ribs.
Lobes and Fissures of the Lungs
- Each lung (left and right) is divided into lobes separated by fissures.
Blood Supply to the Lungs
- Bronchial arteries supply oxygenated blood to all lung tissue except alveoli.
- Alveoli receive deoxygenated blood from the pulmonary arteries.
- Pulmonary veins return oxygenated blood from the lungs to the heart.
Pulmonary Ventilation (Breathing)
- Air flows between the atmosphere and alveoli due to pressure differences created by the contraction and relaxation of respiratory muscles.
- Boyle's Law: The volume of a gas is inversely proportional to its pressure.
Pressure Changes in Pulmonary Ventilation
- Negative respiratory pressure is less than atmospheric pressure; inhalation requires negative pressure to draw air into lungs.
- Positive respiratory pressure is greater than atmospheric pressure.
- Intrapulmonary pressure (Palv): pressure within the alveoli
- Intra-pleural pressure (Pip): pressure within the pleural cavity
Pneumothorax
- Presence of air or gas in the pleural cavity.
- Leads to lung collapse (atelectasis).
Inhalation/Inspiration
- Air movement into the lungs.
- Diaphragm contracts, rib cage expands, lung volume increases, and pressure decreases.
Exhalation/Expiration
- Air movement out of the lungs.
- Diaphragm relaxes, rib cage moves down and inward, lung volume decreases, and pressure increases.
Lung Volumes and Capacities
- Measurements of lung air volumes and capacities, including tidal volume (TV), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), and residual volume (RV); various capacities using combinations of lung volumes
- VC (Vital Capacity), TLC (Total Lung Capacity), IC (Inspiratory Capacity), and FRC (Functional Residual Capacity)
COPD (Emphysema and Chronic Bronchitis)
- Irreversible decrease in the ability to force air out of the lungs.
- Common factors: tobacco smoke and air pollution.
- Emphysema: permanent enlargement of alveoli.
- Chronic Bronchitis: airways inflamed with excessive mucus production.
- Symptoms: dyspnea, coughing, frequent infections, hypoventilation.
Asthma
- Reversible obstructive airway disease.
- Characterized by inflammation, bronchospasm (narrowing of airways), and mucus production.
- Allergic factors are often a critical feature.
- Treatment: bronchodilators and inhaled steroids.
External and Internal Respiration
- External respiration: O₂ diffuses from alveoli into pulmonary capillaries; CO₂ diffuses in the opposite direction.
- Internal respiration: O₂ diffuses from systemic capillaries into tissues; CO₂ diffuses in the opposite direction.
Transport of Oxygen and Carbon Dioxide
- Oxygen: dissolved in plasma and carried by hemoglobin approximately 98.5%.
- Carbon dioxide: dissolved in plasma (10%), bound to hemoglobin (20%), and transported as bicarbonate ions (approximate 70%).
Factors Affecting the Affinity of Hb for O₂
- PO₂, pH, temperature, BPG, and Hb type impact how readily hemoglobin binds and releases oxygen.
Summary of Chemical Reactions During Gas Exchange
- Chemical reactions involving O₂ and CO₂ during gas exchange in both pulmonary and systemic capillaries.
Control of Breathing - Respiratory Centers
- Medullary Respiratory Center: dorsal respiratory group (DRG) mainly responsible for inspiration, ventral respiratory group (VRG) for inspiration and expiration. The pre-Botzinger complex initiates rhythmic breathing.
- Pontine Respiratory Group (PRG): modifying medullary neurons for smoothing out transitions between inspiration and expiration.
Regulation of the Respiratory Center
- Cortical influences allow conscious control of breathing needed to avoid noxious gases or water.
- Chemoreceptors monitor O₂ and CO₂ levels.
- Proprioceptors influence breathing rate changes during movement.
- Inflation reflex limits lung expansion.
- Other factors like limbic system stimulation, pain, blood pressure, and temperature can also influence breathing.
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Description
Test your knowledge of the anatomy of the pharynx and larynx with this quiz. Explore questions about their functions, structures, and the various types of epithelium found in these regions. Ideal for students of anatomy or those interested in human biology.
