A&P ch 1

• Tubes that connect outside air with gas exchange membrane in lungs.
• Pathway for air to move.

• Warms
• Humidifies
• Filters

• Nares: Smallest diameter in upperairway.
• Vibrissae
• Nasal Septum
• Nasal fossae
• Chonanae
• Turbinates

• Pharynx: Behind nasal cavity and extends to larynx.
• Nasopharynx: Behind nasal cavity down to soft palate
• Oropharynx: Behind oral cavity from soft palate to base of tongue
• Laryngopharynx: Below base of tongue and above larynx

• Cartilaginous cylindrical structure
• Acts as a valve at entrance to trachea (glottis: opening into trachea)
• Containing a vocal cords
• Thryoid cartilage (main cartilage of larynx)

Rima glottidis or glottis. Can open and close. Helps generate pressure to cough.

• Vocal cord edema (croup; stridor)
• Laryngeal reflex( laryngospasm)

• 8-20 ventrally C-shaped cartilages
• From c6 to t5 (behind angle of louis)
• 11cm long in adults
• 1.5-2.5 cm in diameter

• Bifurcation of trachea into right and left bronchi
• right broncus at 20-30 degree from midline
• left broncus at 45-55 degree from midline
• air is 100% saturated and at 37C at this point.

• Contain less than 1mm in diameter
• Contain no cartilage
• Contain bronchial smooth muscle
• Smooth muscle contractions can nearly close the bronchioles (Broncospasm and bronchoconstriction)

Terminal bronchioles branch to form respiratory bronchioles

• Mucous secreting epithelium lines lumen of airway
• Basement membrane is next
• Lamina propria contains: Smooth muscle, elastic fibers, blood vessels, nerves.
• Epithelium + Lamina propria = Respiratory Mucosa

• Below mucosa
• contain mucous glands (submucosal glands)

• Surrounds cartilaginous airways and blood vessels
• Ends at bronchioles

1. Ciliated epithelial cells

• 2. Mucous blanks
• Two layers of mucus: gel and sol

• 3. Cilia reach into gel layer exert rapid, forward stroke
• pull gel and layer toward pharynx

• 4. Impairment
• Cigarette smoke
• airpollution
• dehydration

Eosinophils - Associated with asthma caused by allergens

Neutrophils - Associated with bacterial infections

Migrate to airways to phagocytize bacteria

Mast cells - On ephithelial surface of airways. mediators of inflammation released from granules

• Movement of water into airway lumen
• Mechanism: Chloride
• 1. (Cl-) ion is secrted into airway through Cl- channel
• 2. Sodium (Na+) follows Cl- to maintain electrical neutrally.
• 3. Water follows Na+ into airway lumen, hydrating mucus and faciliating ciliary function.

• 300 million alveoli in adult lungs:
• _{50-100 m2 gas exchange area}
• 100 to 300 microns (um) in diameter

• Pulmonary Capillaries:
• _{in contact with aveolar membrane}
• just large enough to follow passage of red blood cells
• faciliatate gas exchange.

• Thin blood air barrier:
• less than 0.5 um thick

• Composed of:
• Alveolar epithelium
• epithelial basement membrane fused with endothelial basement membrane
• capillary endothelium

• Type I epithelial cells:
• comprise most of alveolar surface area
• extremely flat

• Type II epithelial cells:
• compact, polygonal shaped
• protrude into alveolar airspace
• contain lamellar bodies
• secrete surfactant.