Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
19 Cards in this Set
- Front
- Back
|
hormone type:
pituitary thyroid (TH) |
-peptides or aa's
-a single aa |
|
|
daily thyroid output
daily iodine requirement daily turnover by thyroid |
- 100-150microg of T3+T4
-same. -500microg |
|
|
how does circulating iodide enter the thymus
|
-actively transported into follicular cells (iodide trap)
-diffuses into colloid |
|
|
what happens to iodide once in (colloid/follicular cell?) (3)
|
-oxidized into iodine
->incorporated into tyrosine residues (thyroglobulin)-> diiodotyrosine ->2 diiodotyrosines condense into 1 tetraiodotyrosine (thyroxine) i.e. - I- -> I -> DIT -> T4 |
|
|
how are T3/T4 released into the blood
bound or free amount |
-peptide digestion (protease?) in thyroid cell
-mostly protein bound -35mg of T3, 90mg of T4 |
|
|
I- transporters in basal membrane (2)
|
- Na+/K+ pump w/ I-/Na+ cotransporter (uses Na+ gradient)
-accessory pump which utilizes ATP directly |
|
|
peroxidase: functions in thyroid (2)
|
- I- -> I (oxidation)
- incorporation of I into TG |
|
|
Pituitary gland regulation of thyroid (5)
|
-via TSH (aka thyrotropin)
-stims I- pumps -ups T3/T4 output -downs colloid material -produces hyperplasia of thyroid cells |
|
|
what controls release of TSH
|
-TRH (thyrotropin releasing hormone) from hypothalamus
|
|
|
TSH: mechanism (2)
|
-membrane receptor on follicular cells
-cAMP cascade |
|
|
T3 mechanism
|
-enters cell
-binds NUCLEAR recepter -enhances transcription for selected enzymes |
|
|
TH: effects (5)
|
-growth/differentiation
-stim of carb, lipid metabolism -ups basal metabolic rate -downs body weight -ups heart rate, contractility |
|
|
is T3 or T4 more active?
How much more? Is this important? |
-T3
-?? -not so much b/c T4 is converted into T3 in the (target tissue?) |
|
|
tests of thyroid function (4)
|
-basal metabolism
-protein bound iodine -radioactive iodine uptake thyroid scan following radiocactive iodine admin |
|
|
TSH tests
|
-T3 in blood
-biopsy |
|
|
Grave's disease:
def symptoms (5) |
-hyperthyroidism
-toxic goiter -hexophtalmus -adenomas -upped metabolism, heat, heart rate -weight loss |
|
|
goiter is a consequence of
|
-excessive TSH, TRH or LATS
|
|
|
TSI:
def action goiter? |
-thyroid stimulating immunoglobulin (LATS??)
-stims T3/T4 production, but is immune to negative feedback -goiter forms |
|
|
thyroid tumor:
effects goiter? |
- ups T3/T4, low TSH (b/c of feedback inhibition)
- no goiter |
