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Questions and Answers
Which of the following structures is part of the lower respiratory tract?
Which of the following structures is part of the lower respiratory tract?
Which of these structures is NOT part of the conducting zone of the respiratory system?
Which of these structures is NOT part of the conducting zone of the respiratory system?
What is the primary function of the structures within the conducting zone?
What is the primary function of the structures within the conducting zone?
In which of the following structures does the exchange of oxygen and carbon dioxide primarily occur?
In which of the following structures does the exchange of oxygen and carbon dioxide primarily occur?
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Which of the following correctly lists structures found within the respiratory zone?
Which of the following correctly lists structures found within the respiratory zone?
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Which of the following is NOT a primary function of the respiratory system?
Which of the following is NOT a primary function of the respiratory system?
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Which type of epithelium is primarily found lining the nasal cavity near the pharynx?
Which type of epithelium is primarily found lining the nasal cavity near the pharynx?
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What is the function of the hard palate in relation to the nasal cavity?
What is the function of the hard palate in relation to the nasal cavity?
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During swallowing, which structure closes off the nasopharynx?
During swallowing, which structure closes off the nasopharynx?
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The larynx is primarily responsible for protecting which structure?
The larynx is primarily responsible for protecting which structure?
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Which pair of cartilages is directly responsible for changing the position and tension of the vocal cords?
Which pair of cartilages is directly responsible for changing the position and tension of the vocal cords?
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Which of the following describes the superior ligament of the vocal cords?
Which of the following describes the superior ligament of the vocal cords?
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What causes the vibration of the vocal cords that produces sound?
What causes the vibration of the vocal cords that produces sound?
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Which of the following is NOT considered an articulator that controls laryngeal airflow for sound production?
Which of the following is NOT considered an articulator that controls laryngeal airflow for sound production?
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What is a characteristic difference of male vocal cords in relation to pitch?
What is a characteristic difference of male vocal cords in relation to pitch?
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What is the primary function of the laryngeal muscles during swallowing?
What is the primary function of the laryngeal muscles during swallowing?
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What type of tissue lines the trachea and is responsible for mucus secretion?
What type of tissue lines the trachea and is responsible for mucus secretion?
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What is the function of the C-shaped cartilage rings in the trachea?
What is the function of the C-shaped cartilage rings in the trachea?
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Which of the following describes the posterior wall of the trachea?
Which of the following describes the posterior wall of the trachea?
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What is the carina, and what is its primary function?
What is the carina, and what is its primary function?
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Which primary bronchus is more likely to be obstructed by a foreign object?
Which primary bronchus is more likely to be obstructed by a foreign object?
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Where does the trachea divide into the left and right primary bronchi?
Where does the trachea divide into the left and right primary bronchi?
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Besides acting as an air passage, what other function does the trachea serve due to its structure?
Besides acting as an air passage, what other function does the trachea serve due to its structure?
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Study Notes
Respiratory System Overview
- The respiratory system is responsible for gas exchange, moving air through lungs, protecting respiratory areas, producing sound and providing olfactory senses.
- Structures are divided into upper and lower respiratory tracts.
- Upper respiratory tract includes the nose, pharynx, nasal cavity, and paranasal sinuses.
- Lower respiratory tract includes the larynx, trachea, bronchi, bronchioles, and alveoli.
- The system is further categorized into a conducting and respiratory zone.
- The conducting zone transports air, but doesn't participate in gas exchange. It comprises nasal cavity, nasopharynx, oropharynx, laryngopharynx, larynx, trachea, bronchi, and all bronchioles except respiratory bronchioles that filter, warm, and humidify the air.
- The respiratory zone, comprising respiratory bronchioles, alveolar ducts, and alveolar sacs, is where gas exchange occurs.
Nasal Cavity
- The nasal septum divides the nasal cavity.
- The hard palate forms the floor, separating the nasal cavity from the mouth cavity.
- Bony ridges called conchae increase the surface area of the nasal cavity, causing air to churn.
- Paranasal sinuses open into the nasal cavity and are lined with mucous membranes.
- Nasolacrimal ducts connect the eyes to the nasal cavity.
- Olfactory receptors are located at the superior part of the nasal cavity.
- The lining includes stratified squamous epithelium and coarse hairs to trap dust and large particles.
- Near the pharynx, the lining includes pseudostratified columnar cells and goblet cells. This promotes mucus secretion.
- The nasal cavity has a notable role in filtering, warming, and humidifying air. A sneeze reflex protects the nasal passage.
Paranasal Sinuses
- Frontal sinuses
- Ethmoid sinuses
- Maxillary sinuses
- Sphenoid sinuses
Pharynx
- The pharynx is shared by the digestive and respiratory systems.
- It's divided into three parts: nasopharynx, oropharynx, and laryngopharynx.
- The nasopharynx, lined with pseudostratified columnar epithelium, is a superior part that is enclosed by the uvula during swallowing.
- The oropharynx, lined with stratified squamous epithelium, connects to the oral cavity.
- The laryngopharynx, extending from the epiglottis to the esophagus, is the lower part of the pharynx.
Larynx
- Air passes through the glottis on its way to the lungs.
- The larynx protects the glottis.
- Nine cartilages form the larynx.
- Three are large cartilages: thyroid, cricoid, and epiglottis.
- Six are paired cartilages: cuneiform, corniculate, and arytenoids
- Arytenoids change the position and tension of vocal cords.
- Vocal cords are the primary source of voice production.
- Two pairs of ligaments form the vocal cords: the superior vestibular fold (false vocal cord), and the inferior true vocal cord.
- Muscles control the tension and open the glottis.
- Moving air through vocal cords causes them to vibrate, producing sound.
- Male vocal cords tend to be thicker and longer, producing lower-pitched voices affected by testosterone
Trachea
- Inferior to the cricoid cartilage, the trachea extends from the larynx to the mediastinum.
- It divides into left and right primary bronchi at the fifth thoracic vertebra.
- It's lined with pseudostratified epithelium containing goblet cells, responsible for mucus secretion.
- The trachea's C-shaped hyaline cartilage strengthens the trachea and prevents it from collapsing. The posterior wall lacks cartilage, facilitating esophagus expansion when food is swallowed,
- The trachea's posterior wall contains connective tissue and smooth muscle, enabling contraction during coughing.
- The last tracheal cartilage has a sensitive posterior projection called the carina, the most sensitive part of the trachea and plays a role in triggering the cough reflex.
Bronchi
- The trachea bifurcates into two main bronchi.
- The right main bronchus is wider, shorter, and more vertical than the left, making it more prone to foreign object obstruction.
- Air reaching the bronchi is significantly filtered, warmed, and humidified.
- The bronchi are lined with pseudostratified columnar epithelium and supported by C-shaped cartilages.
Bronchial Tree
- Main bronchi further divide into lobar bronchi (secondary bronchi), with three on the right and two on the left.
- Lobar bronchi divide into segmental bronchi (tertiary bronchi).
- The divisions continue to smaller bronchi until they become bronchioles with a diameter less than 1 mm.
- Tertiary bronchi supply air to a single bronchopulmonary segment.
Bronchioles
- The final bronchioles (terminal bronchioles) lack alveoli.
- Bronchioles with alveoli are called respiratory bronchioles, leading to alveolar ducts.
- Alveolar ducts have multiple openings into alveoli (small air sacs).
- Elastic fibers surrounding alveoli assist in expansion and recoil without collapse.
Alveolar Ducts and Alveoli
- Respiratory bronchioles end in ducts and sacs, forming the respiratory membrane.
- The respiratory membrane has six layers: a thin fluid layer, alveolar epithelium (squamous), basement membrane, interstitial space, basement membrane of capillary endothelium, and capillary endothelium (squamous).
Lungs
- Lungs are divided into lobes, with three on the right and two on the left separated by fissures..
- The left lung has a concavity on its medial surface known as the cardiac notch.
Pleural Cavities and Membranes
- Each lung is covered by a pleura—a serous membrane lining the pleural cavity.
- Parietal pleura attaches to the walls of the pleural cavity..
- Visceral pleura adheres to the lung surface.
- Pleural fluid fills and lubricates the space between the pleurae.
Pulmonary Ventilation
- Air movement is governed by Boyle's Law, where pressure and volume are inversely related.
- Inhalation involves diaphragm and rib cage movement causing thoracic volume expansion, creating lower pressure than atmospheric pressure in the lungs and forcing air to flow into the lungs. Exhalation involves the opposite process resulting in air flowing out of the lungs.
Respiration
- Respiration comprises four processes: pulmonary ventilation (breathing in and out), external respiration (gas movement between lungs and blood), gas transport, and internal respiration (gas movement between blood and tissues)
Gas Exchange
- Differences in partial pressures, short diffusion distance, high surface area of alveoli, and coordinated blood flow and airflow enhance gas exchange efficiency in the lungs and body tissues.
Gas Laws in Respiration
- Dalton's Law: Individual gases in a mixture exert pressures proportionate to their abundance in the mixture.
- Henry's Law: The amount of a gas in solution is directly proportional to its partial pressure.
Table 23.2 - Partial Pressures of Gases
- A table showing different partial pressures (in mm Hg) of various gases, in dry air, humidified air, alveolar air and expired air.
Respiratory Centres of the Brain
- Respiratory rhythms are controlled by medullary centers (dorsal respiratory group and ventral respiratory group) and pons centers (apneustic and pneumotaxic centres)
- Sensory input from chemoreceptors (responding to carbon dioxide, oxygen, and pH levels), baroreceptors, as well as stretch receptors modify the respiratory centers.
Respiratory Reflexes
- Chemoreceptor reflexes (responding to CO2 levels), Baroreceptor reflexes, Hering-Breuer reflexes (monitoring lung inflation), Protective reflexes like coughing and sneezing, modify respiratory centres' activities.
Voluntary Control of Respiration
- Conscious thought affects the respiratory rate through areas in the hypothalamus.
- Emotional states affect the respiratory rate by impacting the sympathetic and parasympathetic nervous systems.
Respiratory Disturbances and Control Mechanisms
- Factors like exercise, disturbance, or changes in blood components (e.g., CO2, O2, pH) stimulate sensors (e.g., carotid sinus and aortic arch chemoreceptors, and central chemoreceptors) which send information to the respiratory centers in the brain, resulting in adjustments to breathing to maintain homeostasis.
Respiratory Capacity Volumes
- Measures of lung volume including Tidal volume (TV/VT), Inspiratory reserve volume (IRV), Expiratory reserve volume (ERV), Residual volume (RV), Inspiratory capacity (IC), Functional residual capacity (FRC), and Vital capacity (VC), and Total lung capacity (TLC).
Aging and Respiration
- Respiratory efficiency decreases with age due to: deterioration of elastic tissues leading to diminished lung compliance and vital capacity; restrictive effects of arthritic changes in chest movements; and possible development of emphysema.
Respiratory diseases
- Emphysema, Chronic bronchitis, Bronchial edema affects gas exchange processes.
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Description
Test your knowledge on the respiratory system, its structure, and function. This quiz covers both the upper and lower respiratory tracts, as well as the conducting and respiratory zones. Enhance your understanding of how our body exchanges gases and the importance of each part of the respiratory system.
