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MODULE 18:
THE RESPIRATORY SYSTEM
PART 2 OF 7
Between attacks, Stina’s lungs work normally — clear breath sounds, no wheeze, normal oxygen saturation; the disease is episodic, not chronic lung disease.
Slide 1 Transcript
PATIENT CHART
STINA
THIS PART
Ages 45
PRESENTING WITH
Unilateral chest pain, friction rub, small effusion
ACTION TAKEN
Corticosteroids
DIAGNOSIS
The FMF Serositis Triad
CHART CLUES
COLLECTED AS YOU GO
Recurrent Unilateral Pleuritic Pain
Normal Airway Function Between Attacks
Intact Gas Exchange During Pleurisy
Reduced Tidal Volume from Pain-Limited Excursion
Preserved Acid-Base Balance Between Attacks
Serositis of the Pleura
The FMF Serositis Triad
Put your money down: If Stina’s airways are wide open and clear, why does breathing still hurt during an attack?
On a calm day Stina breathes twelve thousand times before lunch without a thought — clear sounds, normal oxygen. Commit now: when the pain returns, is it because a tube narrowed somewhere on this journey, or because something outside the tubes has caught fire?
Pick the answer you believe now. We’ll come back to it later!
Twelve Thousand Breaths Before Lunch
On a quiet day, with no pain to splint her ribsCurved bones forming the rib cage; articulate with thoracic vertebrae and most with the sternum., Stina breathes the way the rest of us forget we do. Each breath begins at her nose, where turbinate bones warm the air to body temperature, wet it to full humidity, and trap dust on a sheet of mucus. From there the air drops through the pharynxThe muscular passageway connecting the mouth to the esophagus and larynx., past the guarded gate of the larynxThe voice box; contains vocal cords and connects the pharynx to the trachea., and into the trachea — held permanently open by C-shaped rings of cartilageA flexible connective tissue found in joints, the ear, nose, and rib cage. Cartilage can be of three — which forks into two bronchiThe large airways that branch from the trachea into the lungs, dividing into smaller bronchioles. that branch again and again toward passages too small to see.
Nose and Nasal Cavity
The air’s first conditioning — warmed, wetted, filtered.
Slide 2 Transcript
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Single Choice: How does the nasal cavityThe internal space behind the nose that filters, warms, and humidifies incoming air. condition incoming air?
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Mark the Words: Mark the features of respiratory mucosaThe innermost lining of the digestive tract that contains mucus-secreting cells for protection and a; leave the others unmarked.
The Pharynx
A shared crossroads for air and food, in three regions.
Slide 3 Transcript
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Drag the Words: Place nasopharynx, oropharynx, and laryngopharynx and their linings.
Two Zones, Two Jobs
Anatomists split the journey in two. The conducting zone — nose, pharynx, larynx, trachea, bronchi, bronchiolesSmall airways branching from the bronchi that lead to alveoli; lack cartilage and control airflow wi — is plumbing: it carries, cleans, warms, and humidifies air but does no gas exchange, which is why it’s called anatomical dead space. The respiratory zone — respiratory bronchiolesSmallest bronchioles leading to alveolar ducts and alveoli., alveolar ducts, and some three hundred million alveoliMicroscopic air sacs in the lungs where gas exchange occurs between air and blood. — is where the trade happens. Upper airway versus lower airway is a second useful split, the one clinicians reach for first.
The Larynx
Voice box and airway guardian — the epiglottisA flap of cartilage that covers the trachea during swallowing to prevent food from entering the airw on duty.
Slide 4 Transcript
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Fill in the Blanks: Name the laryngeal cartilages and the flap that guards the airway.
The Trachea
A ringed, self-cleaning tube that can’t collapse.
Slide 5 Transcript
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Single Choice: Why are the tracheal cartilage rings C-shaped rather than full O’s?
The Bronchial Tree
Branching ever smaller — and where airflow resistanceThe opposition to airflow in the respiratory tract, influenced by airway diameter. really lives.
Slide 5 Transcript
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Multiple Choice: Where is airway resistance greatest, and why?
Her Trouble Isn’t in the Tubes
For Stina the distinction matters: her trouble is not in these tubes at all. Between attacks the air moves freely, her breath sounds are clear, her oxygen saturationThe percentage of hemoglobin molecules carrying oxygen. is normal — this is episodic serosal disease, not chronic lung disease. Her enemy waits on the outside of the lung, in the membrane that lets the lung slide. Ruling the airways healthy is exactly how we corner the real culprit.
Wall by Wall
The lining changes as the tube shrinks.
Slide 6 Transcript
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Drag the Words: Order the wall changes from trachea to bronchiole.
Airway Smooth Muscle
PlaceWidening and narrowing on demand — the asthmaA chronic condition characterized by airway inflammation, narrowing, and excessive mucus production, target.older
Slide 6 Transcript
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Summary: Pick the true statement about bronchoconstriction and resistance.
FINDING!
Normal Airway Function Between Attacks
Between flares Stina has clear breath sounds, no wheeze, and normal oxygen saturation — the conducting and respiratory zones are healthy. Chart entry: episodic serosal disease, not chronic lung disease; the airways are open, which points the diagnosis outward to the pleuraThe double-layered membrane surrounding the lungs and lining the thoracic cavity..
Confirm or refute your bet: If Stina’s airways are wide open and clear, why does breathing still hurt during an attack?
Now that you’ve walked the air from nostril to alveolus, return to the bet. Nothing on this journey is narrowed — her airways are open and her oxygen is fine. Chart entry: normal airway function between attacks, isolating the disease to the lining outside the lung.
Slide 7 Transcript
NEXT PART
At the very end of the tubing waits the place where breath becomes blood — a membrane so thin a single molecule of oxygen can cross it in a heartbeat.
QUICK QUESTIONS
QUICK QUESTIONS
List of terms
- ribs
- pharynx
- larynx
- cartilage
- bronchi
- nasal cavity
- cells
- cilia
- mucosa
- bronchioles
- respiratory bronchioles
- alveoli
- epiglottis
- resistance
- oxygen saturation
- asthma
- pleura