3. • Nose- lined with mucous membranes. Air
is warmed, filter and moistened
• Pharynx or throat- 3 sections: upper,
middle and lower. Esophagus branches
off here
• Larynx- voicebox. Epiglottis closes the
opening during swallowing
• Trachea- windpipe, lined with c-shaped
cartilaginous rings
4. • Bronchi (singular
bronchus)- left and
right
• Bronchioles- smaller
divisions of the
bronchi
• Bronchioles end in
small air sacs called
alveoli
5. • Lungs: 2 unequal
lobes
• Covered in a
membrane called the
pleura
6. • Breathing =
ventilation
• Two stages:
inspiration and
experation
• Diaphragm and
intercostal muscles
contract, thoracic
cavity enlarges
7. • External respiration: exchange of O2 and
CO2 between lungs and bloodstream
• Internal respiration: exchange of CO2 and
O2 between cells and bloodstream
