A final comprehensive review of the respiratory system.
a. The epiglottis, a cartilaginous flap, covers the glottis during swallowing to prevent food from entering the trachea.
b. Inspiration is an active process involving muscle contraction, while normal expiration is a passive process involving muscle relaxation.
c. A healthy human breathes 12-16 times per minute.
d. The partial pressure of oxygen (pO2) in deoxygenated blood is 40 mm Hg.
e. The partial pressure of carbon dioxide (pCO2) in oxygenated blood is 40 mm Hg.
f. A chemosensitive area in the pons is highly sensitive to CO2 and H+ ions.
g. Emphysema is a chronic disorder often caused by smoking, leading to a decrease in the respiratory surface area.
h. The role of CO2 in the regulation of respiratory rhythm is quite insignificant.
