autoimmune diseases (presence of ANA and RF), is much more common in
women than men. The striated ducts resorb Na+and secrete K+(answer b)
from the isotonic saliva converting it to a hypotonic state. Na+-independent
chloride-bicarbonate anion exchangers appear to be involved in these
processes by generating ion fluxes into the salivary secretion. The striated
duct is the primary region for electrolyte transport in the salivary gland
duct system. The primary secretion produced by the acinar cells is com-
prised of amylase, mucus, and ions in the same concentrations as those of
the extracellular fluid. In the duct system, Na+is actively absorbed from the
lumen of the ducts, Cl−is passively absorbed [although the tight junctions
between striated duct cells inhibit Cl−from following Na+(answer c)].
HCO 3 −is secreted (answer d);Ca^2 +transport is not a factor (e).The result
is a hypotonic sodium and chloride concentration and a hypertonic potas-
sium concentration.
208.The answer is b.(Guyton, pp 739–741, 746–749, 855–856.)The
autonomic nervous system is the primary regulator of salivary gland func-
tion in contradistinction to the pancreas, which is regulated primarily by
hormones [(cholecystokinin and secretin (answers d and e)]. Parasympa-
thetic fibers carry neural signals that originate in the salivatory nuclei of the
medulla and pons. The sympathetic nervous system originates from the
superior cervical ganglion of the sympathetic chain and stimulates acinar
enzyme production. Elevated aldosterone levels affect the amount and
ionic concentration of the saliva, resulting in decreased NaCl secretion and
increased K+concentration(answer c). Cholecystokinin (pancreozymin)
and secretin are the hormones that regulate acinar and ductal secretions,
respectively, in the exocrine pancreas. Antidiuretic hormone can modulate
salivary gland production (answer a).
209.The answer is b.(Young, p 25. Junqueira, pp 31–32, 49, 330–331,
333–334.)The disease described in the scenario is type I (hepatorenal, von
Gierke) glycogenosis caused by a defect in glucose-6-phosphatase, resulting
in accumulation of glucose-6 phosphate and glycogen in the liver. The cyto-
plasmic inclusions labeled with the arrows in the transmission electron
micrograph are glycogen. The hepatocyte, under the regulation of insulin
and glucagon, stores glucose in its polymerized form of glycogen. In electron
micrographs, glycogen appears as scattered dark particles with an approximate
diameter of 15–25 nm. Lipid droplets appear as spherical, homogeneous
332 Anatomy, Histology, and Cell Biology