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Respiratory Systems
Respiratory Tree
Nasopharyngeal Passages
Nares
• Aka Nostrils• Two pair of nares
– External– Internal (choanae)
• Separated by septum (cartilage and vomer bone)
• Each choanus contains appx. 1000 nasal hairs
Divisions of Nasal FossaRespiratory
• Contains three conchae (superior, medial, inferior) that alter airflow through nasal fossa
• Cools, filters and moistens air
Olfactory
• Cilia protrude through mucus covered epithelium.
• Cilia harbor 40 million olfactory receptor neurons capable of detecting 10,000+ odors
Nasal Cycle• Blood flow to nasal
conchae alternates every 2-2.5 hours, effectively changing which nostril we breathe through
• Example of a chaotic ultradian cycle (alternating throughout 24 hr period) controlled by hypothalamus
Pharynx
Pharyngeal Form & FunctionForm:
• Nasopharynx• Oropharynx• Larygopharynx
Function
• Common conductive pathway for digestive and respiratory system
Tonsils
• Lymphoid tissue = first line of immune defense for aerodigestive tract
• Largest pre-puberty; atrophy after puberty
Epiglottis
• Form:– Elastic cartilage– Contains gustatory
papillae (taste buds)• Function:
– Swallowing elevated hyoid bone, causing epiglottis to close off trachea, preventing aspiration
Larynx
Laryngeal Form & FunctionForm:
• 9 cartilaginous rings attached to hyoid bone
• Vestibular folds (protection)
• Mucosal folds (vibration)
Function
• Organ of phonation (vocal sounds)
In infancy, larynx corresponds to C2-C3 vertebrae
As child ages, larynx descends to C5-C6, allowing for development of speech
Trachea
Tracheal Form & Function
• Form• 22mm diameter x
10-16cm length• Ventral to
esophagus• C –shaped
cartilaginous rings• Mucosal • Ciliated
• Function• Conduct air to
bronchi
BRONCHI
Broncheal Form & FunctionForm
• D-shaped tubes with attached visceral muscle
• Each bronchus subdivides into– 2-3 Lobular
Bronchi• 10 bronchioles
– Terminal bronchioles
» Respiratory bronchioles
Function
Bifurcation of airflow from trachea to lungs
Lungs
Divisions of the Mammalian Lung
• Lobes– 3 right/2 left– Each lobe has
discreet Pleural Cavity for protection and lubrication
• Segments• Lobules
Pleurisy (pleuritis) is the inflammation of the pleural lining Inhalation and exhalation cause the pleura to rub against
each other, causing intense chest pain
ALVEOLI
ALVEOLAR FORM• 2-11 alveolar ducts per
respiratory bronchiole, each containing 5-6 alveolar sacs
• 700 million alveolar sacs = ~70-100 m2 surface area
• Interior of alveolus contains squamous epithelium, pulmonary surfactants and macrophages
• 70% of alveolus covered with capillary bed
ALVEOLAR FUNCTION
• Primary site of gas exchange in lungs
• Oxygen diffuses from alveolar lumen, through epithelium and into capillary bed.
• Carbon Dioxide diffuses from capillary bed into alveolar lumen
Thoracic Diaphragm
• Dome-shaped musculofibrous septum located between chest and abdominal cavities
• Movement of diaphragm changes pressure in chest cavity, facilitating inspiration and exhalation
What is the connection?
Gas Air entering lungs - Inhaled air
Air leaving lungs - Exhaled air
Oxygen 21% 16%
carbon dioxide 0.03% 3%
Nitrogen 78% 78%
water vapor small amount significantly moist
Inhaled v. Exhaled Air
Nitrogen Narcosis
Why Does Tissue Suffocation Occur When Trapped In A Fire?
Carbon Monoxide & Hemoglobin
Chemical Regulation of Respiratory Rate
• pH of blood measured in carotid arteries (neck)
• Info relayed to pons & medulla of the hindbrain
• If pH is too acidic, rate of breathing must increase
• If pH too basic, rate of breathing must slow down
• Messages sent to diaphragm via Vagus nerve
NEGATIVE PRESSURE BREATHING
RESPIRATION & BOYLE’S LAW
• P1V1 = P2V2
• Ambient Air Pressure = appx. 14.7 lb/in2
• As size of thoracic cavity increases, pressure in chest drops below ambient pressure
• As size of thoracic
cavity decreases, pressure increases above ambient pressure
High Altitude Cerebral Edema
Henry Heimlich
• Developed abdominal thrust maneuver to treat choking (1974)
• Technique downgraded by American Red Cross due to risk of injury (2006)
How Does The Heimlich Maneuver Work In Terms Of Boyle’s Law?
How Does Boyle’s Law Explain A Collapsed Lung?