Thyroid Flashcards
Controls metabolic rate
thyroxin
lowers blood calcium levels by removing from the blood and putting into the bone
calcitonin
Complete lack of thyroid secretion results in the basal metabolic rate of the body to decrease by ___ to ___ %
40 to 50
Extreme excess of thyroid secretion can increase basal metabolic rate by __ to _____ percent above normal
60 to 100
The thyroid is butterfly shaped and located immediately below the _____, anterior and to each side of the trachea
larynx
The thyroid is one of the largest endocrine glands and weighs about
15-20 grams in adults
What three hormones does the thyroid gland produce
Thyroxine (T4), Triiodothyronine (T3), reverse T3 (rT3 - inactive)
Thyroid gland also produces _______ which is important for calcium regulation
calcitonin
Thyroid gland is made of follicles of ____ epithelial cells surrounding a colloid matrix
cuboidal
________ is required for thyroid hormone synthesis
iodine
___ and ___ are the most important thyroid hormones for metabolic control
T4 and T3
The thyroid secretes 93% ______ and 7% _______, though nearly all is converted to ___ in the tissues
Thyroxine (T4) / Triiodothyronine (T3) / T3
__ is 4x more potent than ___, but is more scarce and is cleared more rapidly
T3 / T4
Thyrotropin releasing hormone is released by the _______
hypolthalamus
TRH causes release of ______ by the ____ ______
TSH / anterior pituitary
TSH causes release of __ and ___ from the thyroid gland
T3 and T4
Only _____ TH is active, but over 99% is bound to protein, either Thyroxin bidning globulin or albumin
free
Thyroid hormone is slowly released from ______ and then taken up by ____ _____
protein / peripheral tissues
Peripheral tissues contain _____ that convert ___ to ___ (T3 is more metabolically active)
enzymes / T4 / T3
TH activate _______ processes which increase gene transciption, protein and enzyme production which increases metabolic rate
intracellular
TH increases the size and number of ______, which are the energy generators of cells
mitochondria
T/F It is likely that all cells in the body are targets for thyroid hormones
TRUE
Thyroid hormones in general effect what?
metabolism, growth, development
Thyroid hormone stimulates ________ metabolism by increasing uptake of glucose by cells and by the ___ tract. It further enhances ____,____,____
carbohydrate / GI / glycolysis, gluconeogensis, insulin secretion
Thyroid horomone stimulates fat metabolism by mobilizing lipids, decreasing fat stores and decreasing ___________
cholesterol
Thyroid hormone INCREASES the requirements for vitamins because vitamins are needed for increased _______ synthesis
enzyme
Thyroid hormone increases the basal metabolic rate because metabolism is _______ in almost all cells
increased
Thyroid hormone can decrease body weight but this does not always occur because it can also increase _______
appetite
Cardiovasular effects of Thyroid Hormone - ______ blood flow secondary to vasodilation
increased
Cardiovasular effects of Thyroid Hormone - ______ cardiac output
increased
Cardiovasular effects of Thyroid Hormone - _______ heart strength and heart rate
increased
Cardiovasular effects of Thyroid Hormone - _______ MAP (increased SBP, decreased DBP, increased PP)
normal
Cardiovasular effects of Thyroid Hormone - _______ respiration because more C02 is produced
increased
Cardiovasular effects of Thyroid Hormone - Increased number and affinity of ______ receptors
beta-adrenergic
Cardiovasular effects of Thyroid Hormone - Decreased number of cardiac _____ receptors
alpha
CNS effects of thyroid hormone
increased mentation, but also increased anxiety and neurosis
Muscular effects of thyroid hormone
muscles more vigorous, become weak with protein catabolism
Thryoid hormone sleep effects
causes exhausted/excitable effects, constantly tired but can’t sleep
Endocrine effects of thyroid hormone
increases both secretion by glands, but also need for hormone from peripheral tissues