Endo 3 Flashcards
About 93 % of the active hormones secreted by the thyroid gland is which hormone?
Thyroxine (T4)
Which thyroid hormone is more potent?
T3
Which hormone is the active hormone?
T3
What cells of thyroid gland secretes calcitonin?
Parafollicular cells
____ is required for thyroid hormone synthesis so thyroid follicular cells actively transport it obtained from the diet
Iodine
_____ is capable of producing intracellular I– concentrations that are 20–40 times as great as the concentration in plasma (Secondary active transporter)
Na+/I– symporter (NIS)
What is the name of the channel that brings Cl into T-Thyrocyte cell and secretes iodine out into the colloid (secondary active transporter_
Pendrin
What enzyme is active in the colloid to iodinate thyroglobulin for transport thru the t-thyrocyte cell back into the blood stream?
Peroxidase
What enzyme is active in the colloid to iodinate thyroglobulin for transport thru the t-thyrocyte cell back into the blood stream?
Peroxidase
How do the thyroid hormones get from the T-thyroocytes to the blood?
Simple diffusion
Colloid is internalized by _____
endocytosis
____ is a reservoir of thyroid hormones
Colloid
Is most thyroid bound to proteins or does it circulate freely?
Bound to proteins
Target cells make active T3 by using enzymes called ____ that remove an iodine from T4
Deiodinases/Iodinases
Individual target cells can alter their exposure to T3 by regulating their tissue _____ synthesis.
Deiodinase
If a condition inhibits Deiodinase activity, there could be signs of _____
hypothyroidism
Which thyroid hormone lasts longer but takes longer to take effect?
T4
_____ hormones are involved in the following functions: growth, CNS development, increase cardiac output, increase tissue blood outflow, increase heart rate, increase heart strength, increased rate of respiration, increased BMR, increased NA-K ATPase, increased gluconeogenesis, increased glycogenolysis, increased lipolysis, increased protein snthesis
Thyroid hormones
Which thyroid hormone is the main circulating form responsible for most of the (-) feedback
T4
Is TSH secretion pulsatile or follow circadian rhythms?
Pulsatile
When is the most TSH secreted?
Midnight
When does TSH secretion begin to increase
9 PM
Which hormone Stimulates carbohydrate metabolism–Causes uptake of glucose by cells–Enhances glycolysis & gluconeogenesis–Increases rate of CHO absorption from G.I. tract•Stimulates proteincatabolism & synthesis •Stimulates fat metabolism9•Stimulates oxygen consumption by most metabolically active tissues.•Increased Basal Metabolic Rate (BMR)–Increases lipid mobilization & oxidation of fatty acids by cells–Required to convert beta carotene to vitamin A (Hypothyroid patients have yellowish skin) –Decreases circulating cholesterol levels (Hypothyroidism associated with hyperlipidemia)
Thyroid hormone
____ hormones is needed for NS development, decreases reflex time, muscle tremors, feeling of tiredness but difficulty sleeping (decrease), anxiety, worry, and paranoia
Thyroid hormone
____ hormones acitvate bone formation that causes a need for PTH secretion
Thyroid hormones
_____ hormones have a permisive effect on CV system where there is increased expression of B-adrenergic receptors
Thyroid hormones
____ hormones lead to increased appetite, increased rate of secretion and motility of the GI tract (undersecretion can produce constipation)
Thyroid hormones
____ is an enlarged thyroid that does not indicate functional status
Goiter
Goiter caused by excessive amounts of ____secretion
TSH
High ____ stimulates thyroid to secrete large amounts of thyroglobulin colloid into follicles, resulting in gland enlargement
TSH