81.An 11-year-old boy presents with ciliary dyskinesia, sinusitis, and
bronchiectasis. He has had persistent infections and otitis media since
birth. A PA radiograph shows dextrocardia, and he has a negative saccha-
rin test. In the cross-section of the cilium shown below, which of the fol-
lowing is primarily affected in this disorder?
Epithelium 159a. Structure A
b. Structure B
c. Structure C
d. Structure D
e. Structure E
82.The conversion of sliding to bending in the cilium is accomplished by
which of the following?
a. Restriction of movement by dynein binding of the central microtubules to each
other
b. The bending of the basal bodies against the axoneme
c. Sliding of nexin along the adjacent microtubule doublet
d. Sliding of the radial spokes against nexin
e. Restriction of the microtubule doublets by radial spokes, nexin, and basal bodies