PART 1: Anatomy of Respiration
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🔍 VOCABULARY + DEFINITIONS
Structural Areas:
* Pleura – Double-layered membrane surrounding the lungs; reduces friction.
* Lobes – Sections of the lungs (Right lung: 3 lobes, Left lung: 2 lobes).
* Upper Respiratory Tract – Includes the nose, nasal cavity, pharynx, and larynx.
* Lower Respiratory Tract – Includes the trachea, bronchi, bronchioles, and alveoli.
Muscles:
* Diaphragm – Dome-shaped muscle under lungs; contracts during inhalation.
* External Intercostals – Muscles between ribs that expand the chest during breathing.
Pathway Structures:
* Nostrils – External openings for air intake.
* Nasal Cavity – Warms, moistens, and filters air.
* Oral Cavity – Secondary entrance for air.
* Pharynx – Throat; common pathway for air and food.
* Nasopharynx – Upper portion, behind the nasal cavity.
* Oropharynx – Middle section, behind the oral cavity.
* Laryngopharynx – Lower section leading to the larynx.
* Epiglottis – Flap that prevents food from entering the airway.
* Larynx – Voice box; contains vocal cords.
* Trachea – Windpipe; conducts air to bronchi.
* Pseudostratified Epithelium – Ciliated cells lining airways for cleaning.
* Cilia – Hair-like structures that move mucus and debris.
* Mucus – Traps particles and pathogens.
Airway Branching:
* Left and Right (Primary) Bronchi – First branches off the trachea into each lung.
* Secondary Bronchi – Branches to each lobe of the lung.
* Tertiary Bronchi – Further division within the lobes.
* Bronchioles – Smaller air passages without cartilage.
* Terminal Bronchiole – Last part before alveoli.
* Alveolar Duct – Leads from bronchioles to alveoli.
* Alveoli – Air sacs where gas exchange occurs.
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📊 LEARNING TARGET: Compare Upper vs. Lower Respiratory Tracts
T-Chart Example:
Upper Respiratory Tract
Lower Respiratory Tract
Nose, Nasal Cavity, Pharynx, Larynx
Trachea, Bronchi, Bronchioles, Alveoli
Filters, warms, and moistens air
Conducts air to lungs, gas exchange
Involved in smell and vocalization
Includes respiratory membrane
Contains tonsils and epiglottis
Includes alveolar sacs for gas exchange
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PART 2: Physiology of Respiration
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🔍 VOCABULARY + DEFINITIONS
Processes:
* Pulmonary Ventilation – Movement of air into/out of lungs (breathing).
* Respiratory Gas Transport – Transport of O₂ and CO₂ via bloodstream.
* Inspiration – Breathing in; diaphragm contracts, volume increases.
* Expiration – Breathing out; diaphragm relaxes, volume decreases.
* Internal Respiration – Gas exchange between blood and body tissues.
* External Respiration – Gas exchange between alveoli and blood.
Volumes & Capacities:
* Tidal Volume (TV) – Air moved in/out during normal breathing (~500 mL).
* Inspiratory Reserve Volume (IRV) – Extra air inhaled after normal breath (~3100 mL).
* Expiratory Reserve Volume (ERV) – Extra air exhaled after normal breath (~1200 mL).
* Residual Volume (RV) – Air remaining after full exhalation (~1200 mL).
* Vital Capacity (VC) – Total air that can be exhaled after max inhalation (TV + IRV + ERV).
* Total Lung Capacity (TLC) – VC + RV (~6000 mL in adults).
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📘 LEARNING TARGET: Trajectory of an Oxygen Molecule
Pathway of Oxygen:
1. Enters through Nostrils/Nasal Cavity → filtered, warmed, humidified.
2. Passes through Pharynx → Larynx → Trachea.
3. Travels down Primary Bronchi → Secondary → Tertiary Bronchi.
4. Enters Bronchioles → Terminal Bronchioles → Alveolar Ducts → Alveoli.
5. Gas Exchange at alveoli → O₂ enters pulmonary capillaries.
6. O₂ binds to hemoglobin in red blood cells.
7. Blood transports O₂ via arteries → Body Tissues for Internal Respiration.
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🧮 Lung Capacity in Action (Example)
Let’s say you're taking 12 breaths per minute with a Tidal Volume of 500 mL:
* 12 x 500 mL = 6000 mL or 6 Liters per minute
* During exercise, TV and breathing rate increase dramatically (up to ~100 L/min in elite athletes!)