Respiratory system Aka: what’s the heimlich manuever?
Why the respiratory system? • Large surface area for gas exchange • Move air to gas exchange area • Protect gas exchange area from pathogens, dehydration, extreme temperatures • Make noise! • Assist smelling ( who cut the cheese?).
Air conducting (moving) path • External nares • Nasal cavity • guard hairs • Air warmed and moistened • Nasal septum
More path • Oral cavity • Separated from nasal by palatine/maxillary bones called “hard palate” • Soft palate- fleshy part beyond hard palate • Oropharynx- contains tonsils for protection from foreign bodies • Glottis- hole at start of trachea • Epiglottis- covers trachea • Larynx- contains vocal cords or “voice box”
Cont. • Coughing reflex- triggered when “stuff” hits vocal cords, • “cough”-glottis is closed and pressure built up in lungs until glottis is suddenly released • Tension on vocal cords determines pitch • Trachea- extends from larynx to branching of bronchi, includes rings of cartilage for support
More • Tracheostomy- inserting a tube through anterior tracheal wall. “Stoma” • Bronchi- branching of trachea into primary, secondary and tertiary branches • Bronchioles- when cartilage is no longer present ( less than 0.04 inch in diameter)
Alveola • Sack where gas exchange occurs • Trivia- 150 million alveola / lung • Gives spongy appearance to lung • Simple squamous epithelium • Dust cells- macrophages that roam around eating up dust and debri • Moist alveoli- why? • Surfactant- oily secretion that reduces surface tension of moist alveoli
Air movement • Hypoxia- hypo- low, oxia-? • Anoxia-? • Pulmonary ventilation depends on • Pressure gradient-? • Diaphragm- 75% of pulmonary vent. • Rib cage- 25% of pulmonary vent.
Lung volume/ capacity • Tidal volume- amount of air moved during a single respiratory cycle, normal breath • Expiratory reserve volume- ( forced exhalation volume) amount voluntarily expelled after a regular exhalation • Inspiratory reserve volume- (forced inhalation volume) amount voluntarily inhaled after a regular inhalation • Vital capacity= tidal volume+ERV+IRV, max air you can move