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Questions and Answers
What structures make up the upper respiratory tract?
What structures make up the upper respiratory tract?
Which part of the respiratory system is specifically involved in gas exchange?
Which part of the respiratory system is specifically involved in gas exchange?
What is the primary function of the nasal concha?
What is the primary function of the nasal concha?
Which of the following structures does NOT belong to the conducting zone of the respiratory system?
Which of the following structures does NOT belong to the conducting zone of the respiratory system?
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What are the three anatomical regions of the pharynx?
What are the three anatomical regions of the pharynx?
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What is the role of the Eustachian tubes located in the nasopharynx?
What is the role of the Eustachian tubes located in the nasopharynx?
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How many alveoli are typically found in one lung?
How many alveoli are typically found in one lung?
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Which anatomical feature separates the nasopharynx from the oropharynx?
Which anatomical feature separates the nasopharynx from the oropharynx?
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What functions does the laryngopharynx participate in?
What functions does the laryngopharynx participate in?
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What is the primary purpose of a cricothyrotomy?
What is the primary purpose of a cricothyrotomy?
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Where are the vocal folds located in relation to the esophagus?
Where are the vocal folds located in relation to the esophagus?
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How long is the trachea in adults?
How long is the trachea in adults?
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What do the terminal bronchioles lead directly into?
What do the terminal bronchioles lead directly into?
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Which structure acts as a flap to close the glottic opening during swallowing?
Which structure acts as a flap to close the glottic opening during swallowing?
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Which of the following is true regarding the bronchi?
Which of the following is true regarding the bronchi?
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What are alveoli primarily responsible for?
What are alveoli primarily responsible for?
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Study Notes
Respiratory System Anatomy
- The upper respiratory tract includes the nose, pharynx, and associated structures.
- The lower respiratory tract includes the larynx, trachea, bronchi, and lungs.
Conducting Zone
- The conducting zone brings air to the site of external respiration.
- It's made up of the nose, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles.
Respiratory Zone
- The respiratory zone is the main site of gas exchange.
- It's composed of respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.
Air Traversal of Respiratory Tract
- Air passes through the nasal cavity, pharynx, larynx, trachea, primary bronchi, secondary bronchi, tertiary bronchi, bronchioles, and finally alveoli.
- The lungs have 150 million alveoli.
Nasal Concha
- Nasal conchae increase the surface area of the nasal cavity.
- This allows more air to come into contact with the cavity walls, warming and humidifying the air before it reaches the lungs.
- Openings, or meatuses, exist under each nasal concha for the nasal lacrimal duct (drains sinus secretions and tears into the nose).
Olfactory Nerves
- Olfactory nerves pierce the cribriform plate to carry smell information from the nose to the brain.
Pharynx
- The pharynx is a hollow tube that functions as a passageway for air and food, a resonating chamber, and houses the tonsils.
- The pharynx has three anatomical regions: nasopharynx, oropharynx, and laryngopharynx.
- The nasopharynx contains the pharyngeal tonsils (adenoids) along with Eustachian tube openings (auditory tubes).
- The laryngopharynx lies inferiorly and opens into the larynx and esophagus, participating in both respiratory and digestive functions.
Larynx
- The larynx connects the laryngopharynx to the trachea (the windpipe).
- The thyroid cartilage, the Adam's apple, is a landmark for emergency airway creation (cricothyrotomy).
- Cricothyrotomy is an incision made through the skin and cricothyroid membrane to open a patient's airway.
- The epiglottis is a flap at the entrance of the glottis (opening between vocal folds) that's held anteriorly for breathing and pulled backward to close off the glottic opening during swallowing.
- Vocal folds are located high in the larynx.
Trachea
- The trachea is a semi-rigid tube about 12 cm long.
- It extends from the inferior larynx into the mediastinum and branches into right and left primary bronchi.
- The carina is an internal ridge at the junction of the two primary bronchi that triggers the cough reflex.
Bronchi
- The primary bronchi divide into secondary and tertiary bronchi.
- The tertiary bronchi divide into bronchioles; the smallest are the terminal bronchioles.
Alveoli
- Alveoli are cup-shaped outpouchings (tiny air sacs) where gas exchange between air and blood occurs.
- Alveoli are composed mostly of type I alveolar cells for gas exchange and type II alveolar cells that secrete surfactant preventing alveolar collapse during exhalation.
Lungs
- Each lung is enclosed by a double-layered pleural membrane.
- The parietal pleura lines the thoracic cavity walls.
- The visceral pleura adheres to the lung surface.
- Pleural fluid exists between the layers, reducing friction and creating surface tension allowing sliding.
- The pleura mechanically couples the chest wall and lung, making them move together.
- The apex of the lung is superior and extends above the clavicles.
- The base rests on the diaphragm.
- The cardiac notch in the left lung makes it 10% smaller than the right lung.
Pulmonary Ventilation
- Pulmonary ventilation is the movement of air between the atmosphere and alveoli; it involves inhalation and exhalation.
- The diaphragm is the primary breathing muscle. During inhalation it moves down. During exhalation it moves up.
Measuring Ventilation
- Ventilation can be measured via spirometry.
- A spirometer measures the volume of inspired and expired air.
- Key volumes include: Tidal Volume (Vt), Inspiratory Reserve Volume (IRV), Expiratory Reserve Volume (ERV), Vital Capacity (VC), and Residual Volume (RV).
Transport of O2 and CO2
- In the blood, some O2 dissolves as a gas; most is bound to hemoglobin (Hb).
- Oxygenated Hb is called oxyhemoglobin.
- O2 is transported in the blood (Po2 = 100 mmHg) and is needed in tissues to make ATP (Po2 = 40 mmHg at capillaries).
- CO2 diffuses from tissues (Pco2 = 45 mmHg) to the blood (Pco2 = 40 mmHg).
- SaO2 is the amount of Hb saturated with O2, measuring the percentage of oxygen-bound hemoglobin in arterial blood. It's typically 95-98%.
Respiratory Control and Acid-Base Balance
- The medulla rhythmicity area, in the brainstem, controls basic respiratory patterns.
- The inspiratory center stimulates the diaphragm and intercostal muscles.
- Acid-base balance is maintained, with pH ranging from 7.35 to 7.45 (blood).
Diseases and Disorders
- Asthma is a hyper-reactive airway disease causing wheezing, coughing, and mucus production, typically triggered by allergens.
- Chronic bronchitis and emphysema are caused by chronic irritation and inflammation, often linked to cigarette smoking. Patients frequently cough up green-yellow sputum.
- Pneumonia is an acute infection of the lower respiratory tract where small bronchioles and alveoli fill with inflammatory fluid, usually caused by bacteria, viruses, or fungi.
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Description
Test your knowledge on the anatomy of the respiratory system, including its upper and lower tracts. This quiz covers important components such as the conducting and respiratory zones, as well as air traversal in the respiratory tract.
