CH 37 THYROID AND PARATHYROID AGENTS NUR187 EXAM
QUESTIONS AND VERIFIED ANSWERS
(?) hormone produced by the parafollicular cells of the thyroid; counteracts the
effects of parathyroid hormone to maintain calcium levels
calcitonin
(?) excessive thyroid hormone
hyperthyroidism
(?) lack of sufficient thyroid hormone to maintain normal metabolism
hypothyroidism
THYROID AGENTS
Thyroid Hormones
levothyroxine
ANTITHYROID AGENTS
Thioamides
propylthiouracil
PARATHYROID AGENTS
Antihypocalcemic Agents
calcitriol
Antihypercalcemic Agents
Bisphosphonates
alendronate
,Antihypercalcemic Agents
Calcitonins
calcitonin salmon
The thyroid gland is located in the middle of the neck, where it surrounds the
trachea like a shield. Its name comes from the Greek words thyros (shield) and
eidos (gland). It produces theses three thyroid hormones (?).
It produces thyroid hormones (triiodothyronine—T3 and thyroxine—T4) and calcitonin.
The thyroid gland is made up of cells arranged in circular follicles. The center of
each follicle is composed of colloid tissue in which the thyroid hormones
produced by the gland are stored.
Cells found around the follicle of the thyroid gland are called parafollicular
cells. These cells produce another hormone, calcitonin, which affects calcium
levels and acts to balance the effects of the parathyroid hormone (PTH),
parathormone.
Using iodine that is found in the diet, the thyroid gland produces two slightly
different thyroid hormones: thyroxine, or tetraiodothyronine (T4), so named
because it contains four iodine atoms, which is given therapeutically in the
synthetic form levothyroxine, and triiodothyronine (T3), so named because it
contains three iodine atoms, which is given in the synthetic form liothyronine.
Thyroid hormone regulates the rate of metabolism—that is, the rate at which
energy is burned—in almost all the cells of the body. The thyroid hormones affect
heat production and body temperature; oxygen consumption and cardiac output;
blood volume; enzyme system activity; and metabolism of carbohydrates, fats,
, and proteins. Thyroid hormone is also an important regulator of growth and
development, especially within the reproductive and nervous systems. Because
the thyroid has such widespread effects throughout the body, any dysfunction of
the thyroid gland will have numerous systemic effects.
When thyroid hormone is needed in the body, the stored thyroid hormone
molecule is absorbed into the thyroid cells, where the T3 and T4 are released into
circulation. These hormones are carried on plasma proteins, which can be
measured as protein-bound iodine levels. The thyroid gland produces more T4
than T3. More T4 is released into circulation, but T3 is approximately four times
more active than T4. However, T4 has a longer half-life in the blood and can be
converted to T3 when needed.
Thyroid hormone production and release are regulated by the anterior pituitary
hormone called thyroid-stimulating hormone (TSH). The secretion of TSH is
regulated by thyrotropin-releasing hormone (TRH), a hypothalamic regulating
factor.
The thyroid gland produces increased thyroid hormones in response to increased
levels of TSH. The increased levels of thyroid hormones send a negative
feedback message to the pituitary to decrease TSH release and, at the same time,
to the hypothalamus to decrease TRH release. A drop in TRH levels subsequently
results in a drop in TSH levels, which in turn leads to a drop in thyroid hormone
levels. In response to low blood serum levels of thyroid hormone, the
hypothalamus sends TRH to the anterior pituitary, which responds by releasing
TSH, which in turn stimulates the thyroid gland to again produce and release
QUESTIONS AND VERIFIED ANSWERS
(?) hormone produced by the parafollicular cells of the thyroid; counteracts the
effects of parathyroid hormone to maintain calcium levels
calcitonin
(?) excessive thyroid hormone
hyperthyroidism
(?) lack of sufficient thyroid hormone to maintain normal metabolism
hypothyroidism
THYROID AGENTS
Thyroid Hormones
levothyroxine
ANTITHYROID AGENTS
Thioamides
propylthiouracil
PARATHYROID AGENTS
Antihypocalcemic Agents
calcitriol
Antihypercalcemic Agents
Bisphosphonates
alendronate
,Antihypercalcemic Agents
Calcitonins
calcitonin salmon
The thyroid gland is located in the middle of the neck, where it surrounds the
trachea like a shield. Its name comes from the Greek words thyros (shield) and
eidos (gland). It produces theses three thyroid hormones (?).
It produces thyroid hormones (triiodothyronine—T3 and thyroxine—T4) and calcitonin.
The thyroid gland is made up of cells arranged in circular follicles. The center of
each follicle is composed of colloid tissue in which the thyroid hormones
produced by the gland are stored.
Cells found around the follicle of the thyroid gland are called parafollicular
cells. These cells produce another hormone, calcitonin, which affects calcium
levels and acts to balance the effects of the parathyroid hormone (PTH),
parathormone.
Using iodine that is found in the diet, the thyroid gland produces two slightly
different thyroid hormones: thyroxine, or tetraiodothyronine (T4), so named
because it contains four iodine atoms, which is given therapeutically in the
synthetic form levothyroxine, and triiodothyronine (T3), so named because it
contains three iodine atoms, which is given in the synthetic form liothyronine.
Thyroid hormone regulates the rate of metabolism—that is, the rate at which
energy is burned—in almost all the cells of the body. The thyroid hormones affect
heat production and body temperature; oxygen consumption and cardiac output;
blood volume; enzyme system activity; and metabolism of carbohydrates, fats,
, and proteins. Thyroid hormone is also an important regulator of growth and
development, especially within the reproductive and nervous systems. Because
the thyroid has such widespread effects throughout the body, any dysfunction of
the thyroid gland will have numerous systemic effects.
When thyroid hormone is needed in the body, the stored thyroid hormone
molecule is absorbed into the thyroid cells, where the T3 and T4 are released into
circulation. These hormones are carried on plasma proteins, which can be
measured as protein-bound iodine levels. The thyroid gland produces more T4
than T3. More T4 is released into circulation, but T3 is approximately four times
more active than T4. However, T4 has a longer half-life in the blood and can be
converted to T3 when needed.
Thyroid hormone production and release are regulated by the anterior pituitary
hormone called thyroid-stimulating hormone (TSH). The secretion of TSH is
regulated by thyrotropin-releasing hormone (TRH), a hypothalamic regulating
factor.
The thyroid gland produces increased thyroid hormones in response to increased
levels of TSH. The increased levels of thyroid hormones send a negative
feedback message to the pituitary to decrease TSH release and, at the same time,
to the hypothalamus to decrease TRH release. A drop in TRH levels subsequently
results in a drop in TSH levels, which in turn leads to a drop in thyroid hormone
levels. In response to low blood serum levels of thyroid hormone, the
hypothalamus sends TRH to the anterior pituitary, which responds by releasing
TSH, which in turn stimulates the thyroid gland to again produce and release
