Page 339 - Critical Care Nursing Demystified

324 CRITICAL CARE NURSING DeMYSTIFIED

Teach the importance of taking prescribed medications and not discontinu-
ing them abruptly
Provide meticulous skin and oral care
Assess for signs of dehydration

Assess vital signs for return to normal status
Wear Medical Alert bracelet to identify illness

1 Structure and Function of the Thyroid Gland
The thyroid gland is considered to be the largest endocrine gland. Located at the
front of the neck, it resembles a bow-tie and has two lateral lobes connected by a
band of narrow thyroid tissue known as the thyroid isthmus. The thyroid gland is
highly vascular. Its basic cells of function are known as follicles, filled with the protein
thyroglobulin. A person with a normal functioning thyroid gland is said to be euthy-
roid. Thyrotropin, or TRH, is secreted by the hypothalamus. It activates the release
of the thyroid-stimulating hormone (TSH), which is produced and secreted by the
anterior pituitary gland. The thyroid gland secretes three hormones that affect all
active metabolic processes of the body. These hormones are T3 – triiodothyronine,
T4 – L-thyroxine, and calcitonin. Functions of these hormones include 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.
1. Increasing the effects of epinephrine to activate heat production and
lower serum cholesterol levels.
2. Enhancing the normal development of the central nervous system and
stimulating the growth and normal metabolism of all body cells.
3. Calcitonin lowers serum blood calcium levels and increases calcium
absorption by the bone.
An adequate intake of iodine by ingesting table salt is necessary for the continued
production of these hormones. The iodine is absorbed and concentrated in the
thyroid follicles. Iodine becomes iodide and, aided by thyroxine (an amino acid),
binds to thyroglobulin to become T3 and T4. T3 is five times as potent and more
metabolically active than T4, but most of the thyroid output is in the form of T4.

Conditions Affecting Thyroid Function

An enlarged thyroid or thyromegaly is referred to as a goiter. It is visible and
palpable on the anterior neck and can be noted on inspection if the thyroid
gland is excessively enlarged.
Cretinism is a congenital condition caused by a deficient amount of thyroid
hormones, which produces growth failure, possible mental retardation, lowered