(answer c)].The pineal is innervated by postganglionic sympathetic fibers
in a fashion similar to other glands in the head and neck region (e.g., sali-
vary glands). The adrenal medulla is innervated by preganglionic sympa-
thetic fibers (answer d).Corticotrophs in the anterior pituitary produce
MSH.The pineal does not contain melanocytes or secrete MSH (answer e).
There are age-related changes in the pineal in which the number of concre-
tions and the degree of calcification of the “brain sand” increase. The pineal
can be identified and used as a landmark in radiologic procedures by its cal-
cification.
226.The answer is d.(Sadler, pp 252–253. Kumar, pp 1211–1214. Moore
and Persaud, Developing, pp 304, 307, 318.)The newborn described is geno-
typically female and suffers from adrenogenital syndrome, also known as
congenital virilizing hyperplasia, in which there is a deficiency in the path-
way that leads to cortisol synthesis. The inability to synthesize cortisol in
turn leads to production of high levels of ACTH and ACTH-releasing fac-
tor from the hypothalamus (answer b).The result is hypertrophy of the
fetal adrenal cortex, which is a critical fetal structure that produces dehy-
droepiandrosterone. The excessive production of androgens by the fetal
adrenal leads to masculinization of the female genitalia. Increased secretion
of cortisol cannot occur because of the metabolic defect in this pathway;
therefore, negative feedback control is not functional. The fetal cortex is
part of maternal-feto-placental unit because dehydroepiandrosterone is
used by the placenta to produce estradiol. The fetal adrenal cortex invo-
lutes following birth, causing an overall reduction in the size of the adrenal.
The adult cortex (zona glomerulosa, zona fasciculata, and zona reticularis)
replaces the fetal adrenal cortex. The zona fasciculata and zona reticularis
produce androgens after birth (answer c).Vasopressin [(AVP) also known
as antidiuretic hormone (ADH)] is released by the posterior pituitary and
regulates fluid balance. ADH increases the permeability of the collecting
duct through an aquaporin-mediated mechanism (answer e).Androgen
insensitivity is the cause of testicular feminization and is not a factor in the
adrenogenital syndrome (answer a).
227.The answer is e.(Junqueira, pp 423–428. Kumar, pp 1172–1173. Moore
and Persaud, Developing, pp 215–217.)The patient is suffering from Graves’
disease, an autoimmune disease that occurs much more frequently in women
than in men. Graves’ disease accounts for approximately 85% of diagnosed
Endocrine Glands Answers 351