Page 329 - Critical Care Nursing Demystified

314 CRITICAL CARE NURSING DeMYSTIFIED

sphenoid bone at the site of the “sella turcica.” The pituitary gland is very vas-
cular and well protected in this area. It is highly inaccessible and hard to reach
for purposes of repair. The pituitary gland acts in partnership with the hypo-
thalamus, which actually controls the release and inhibition of its hormones.
The hypothalamus is located above the pituitary gland and is connected to the
posterior pituitary gland by the “pituitary stem”or “infundibular stalk,” also
located at the base of the brain.
Areas of the pituitary gland are listed in Table 7–1.
The use of certain medications can create ADH imbalances. The release of
ADH can be decreased by the use of medications such as Dilantin, chlorprom-
azine, and reserpine. Medications such as barbiturates, anesthetics, vincristine, and
glucocorticoids will stimulate and increase the release of ADH. Other factors that
affect ADH levels are pain, stress, surgery, alcohol, and malignant diseases.

What Went Wrong?
Pituitary malfunctions can lead to significant patient problems. An overproduc-
tion of growth hormone (GH) is almost always caused by a tumor or benign
pituitary adenoma. Excessive secretions of GH (somatotropin) in children prior
to puberty can result in giantism to an excess of 8 ft tall in height. Longitudinal Downloaded by [ Faculty of Nursing, Chiangmai University 5.62.158.117] at [07/18/16]. Copyright © McGraw-Hill Global Education Holdings, LLC. Not to be redistributed or modified in any way without permission.
bone growth occurs because the epiphyseal plate has not fully matured, making
continued long bone growth possible.

2 TABLE 7–1 Areas of the Pituitary Gland
Anterior lobe or Hormones produced are ACTH—or the adrenocorti-
adenohypophysis—the cotrophic hormones, TSH—thyroid-stimulating
largest portion of the hormones, FSH—follicle-stimulating hormones,
pituitary gland LH—luteinizing hormones, growth hormone—
somatotropin, and prolactin, which stimulates
breast milk production during lactation.
Pars intermedia or the Located in the center of the pituitary gland between
intermediate lobe the anterior and posterior portions, it gradually
merges with the posterior lobe in adulthood. Its
function is unclear.
Posterior lobe or An extension of the hypothalamus, which
neurohypophysis collects, stores, and releases hormones produced
by the hypothalamus. The two major hormones
manufactured in the hypothalamus and stored in
the posterior pituitary lobe are oxytocin (Pitocin)
and ADH—antidiuretic hormone (arginine vasopressin
or AVP). ADH is directly responsible for regulating
bodily fluid balance by controlling sodium levels of
extracellular fluid or ECF.