When the radius of the bronchial airways decreases during exhalation, what change
must occur to maintain a constant gas flow?
a. The transthoracic pressure must vary inversely with the fourth power of the radius
b. The transthoracic pressure must vary directly with the fourth power of the radius
c. The transthoracic pressure must remain constant
d. The transthoracic pressure must vary inversely with the second power of the radius
Which of the following physiologic changes occur during sleep?
I. Colonic motility is decreased
II. Penile tumescence occurs during REM
III. Plasma growth hormones peak during Stage N3
IV. The heart rate can increase by up to 35% during REM