Term
| explain thyroid hormones from ingestion of iodine to T3/4 production and storage (7 steps) |
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Definition
1. ingest iodine
2. TSH stimulates iodine uptake and hormone production
3. iodine active transport into thyroid
4. activated with THYROID PEROXIDAZE (using Hb and H2O2)
5. monotyrostol and diiodotyrosyl are produced
6. THYROID PEROXIDASE links AA making T3 and T4 in a 1:4 ratio
7. T3 and T4 are stored in thyroglobulin |
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Term
| explain thyroid hormone release from thyroglobulin to arrival at the tissues (7 steps) |
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Definition
1. thyroglobulin fuses with lysoosme
2. proteolytic enzymes break it into...
- monotyrosyl and dioxotyrosyl which stay in thyroid
- T3/T4 which go into blood
- excess iodine which stays in thyroid
3. T3/4travel in blood on thyroxine binding globulin and albumin
4. T3/4 are released at tissues |
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Term
| what motifications occur to T3/4 at the tissues (2) |
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Definition
diodinase enzymes remove 5' outer ring...
- 5-DI and 5-DII turn T4 to T3 (41% of T3)
- 5-DIII turns T4 into reverse T3 |
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Term
| where are T3 and T4 degraded |
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Definition
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Term
| what are the differences in T3 and T4 elimination |
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Definition
T3 is eliminated in 2 d due to increased protein binding increasing hald life
T4 is eliminated in 6-7d |
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Term
| how does iodine regulate thyroid hormone production |
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Definition
| decreased iodine decrease thyroid hormones which stimulate TSH causing thyroid hypertrophy (gioter) and selective T3 formation |
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Term
| how does the production of thyroid hormone reulate itself |
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Definition
it doesnt
it stops TSH production but increases thyrotropin releasing hormone (TRH) production which cancel |
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Term
| what is the difference in tissue binding and activity of T3 and T4 |
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Definition
T3 binds with 5x higher affinity
T4 binds with lower affinity |
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Term
| what are the 6 areas in general thyroid hormones affect |
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Definition
growth and development
basal metabolic rate
released when cold to regulate body temp
heart
CNS
cholesterol metabolism |
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Term
| how does the thyroid effect growth and development (5) |
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Definition
differentiation and myelination of cnS
potentiation of GH, PTH, and calcitonin |
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Term
| in what organs does the thyroid hormone effect on basal metabolic rate have the most effect (4) |
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Definition
| heart, muscle, liver, kidney |
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Term
| what changes do thyroid hormones cause in the heart (4) |
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Definition
sensitize it (synergistic)
increase CO, HR, contractility |
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Term
| what effects do thyroid hormones have on the CNS |
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Definition
| sensitize catecholamine receptors (synergistic) |
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Term
| what does thyroid hormone do to cholesterol metabolism |
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Definition
stimulates metabolism of cholesterol to bile acids
important! lack can cause hypercholesterolemia |
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Term
| what is the name for adult hypothyroidism |
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Definition
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Term
| what is the name for child hypothyroidism |
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Definition
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Term
| what are the 9 signs of child hypothyroidism |
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Definition
impaired growth
mental retardation
pot belly
dwarfism
lethargy
hypothermia
slow HT
poor appetite
death if untreated |
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Term
| what are the 8 signs of adult hypothyroiodism |
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Definition
pallid expression
blank expression
dry skin
brittle nails
weakness
reduced CO
fatigue
cold intolerence |
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Term
| what are two diseases of hyperthyroidism |
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Definition
| graves and plummers disease |
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Term
| what are 7 characteristics of graves disease |
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Definition
diffuse toxic goiter
exophthalmos: big eyes
hot moist skin
forced rapid heart beat
angina
arrhythmia
heart failure |
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Term
| what are 4 causes of graves disease |
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Definition
autoimmune: IgG bind to TSH receptor
chorionic: placental secretion of TSG stimulates receptors in pregnancy |
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Term
| what are 6 signs of plummer's disease |
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Definition
toxic nodular goiter
hot moist skin
forced rapid heart beat
angina
arrhythmia
heart failure |
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Term
| what are 5 general signs of hyperthyroidism |
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Definition
hot moist skin
forced rapid heart beat
angina
arrhythmia
heart failure |
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Term
| what are the 3 treatments for hyperthyroidism |
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Definition
surgical removal of thyroid
local radiation with radioactive iodine
anti thyroid agents |
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Term
| what causes a thyroid storm (7) |
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Definition
| complication of hyperthyroidism triggered by stress, thyroid surgery, trauma, diabetic ketoacidosis, labor, heart disease, radioactive iodine |
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Term
| what are the 7 treatments of a thyroid storm |
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Definition
fluids
anti-pyretics
cooling blankets
propylithiouracil in large doses
iodates
B blockers and Ca can control tachyarrhytima
dexamethasone |
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Term
| what are the three thyroid hormone drugs, what hormone is each |
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Definition
desiccated thyroid - T3 and T4
levothyroxine - T4
liothyroxine - T3 |
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Term
| what are the advantages of using liothyronlne over levothyroxine (4) |
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Definition
| liothyroline does not have to be converted for full potential, fast onset, good absorption, good when someone has problem with T4 to T3 conversion enzyme |
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Term
| what is the clinical use for thyroid hormones (3) |
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Definition
hypothyroidism
non-toxic goiter
replacement therapy |
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Term
| what are the contraindications to thyroid hormones (3) |
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Definition
acute MI
increase anticoagulant effects
reduce digitalis effects |
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Term
| what are the 3 side effects or problems with desiccated thyroid |
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Definition
antigenic because it comes from pork
highly variable biological activity
religous objections to treatment |
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Term
| what are the two anti-thyroid or thiroureylenes |
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Definition
| propylthiouracil and methimazole |
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Term
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Definition
stop iodiniation of throsyl in thyroglobulin
block thyroid peroxidae inhibiting coupling reaction
prophylthiouracil- blocks conversion of T3 to T4 |
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Term
| what are the three side effects of anti-thyroids |
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Definition
agranulocytosis
marrow aplasic (improves on DC)
secreted into breast milk |
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Term
| what can anti-thyroids be used to treat (7) |
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Definition
graves disease
small goiters
mild hyperthyroidism
deplete thyroid hormone before radiation hyperthyroidism in elderly
after radiation
prethyrodectomy- prevent surge in surgery
thyroid storm - prophylthiouracil due to T3 to T4 ability |
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Term
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Definition
saturated potassium iodide prevents thyroid hormone release
inhibits hormone synthesis by decreasing TSG and blcking its action (wolff chickoff effect) |
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Term
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Definition
rebound hyperthyroidism
angioedema
hypersensitivity
iodism |
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Term
| what is iodism, what are 7 signs |
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Definition
chronic intoxication of iodine
burning bouth, throat, eyes, headache, productive cough, gastric irritation, skin lesions |
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Term
| what are the three uses of iodine |
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Definition
reduce vascularity and increase gland firmness
thyroid storm prevention
pre surgery |
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Term
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Definition
gets trapped in thyroid and B-rays destory parenchyma
B-rays only destory bad tissue |
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Term
| what are three side effects of radioactive iodine |
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Definition
cannot use in pregnancy
delayed hypothyroidism
chromosomal abberations (cannot use in kids and pregnancy) |
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Term
| what is the half life of radioactive iodine |
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Definition
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Term
| what is the use of radioactive iodine |
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Definition
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Term
| what is another name for radioactive iodine |
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Definition
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