Endocrine physiology - Thyroid Flashcards
What kind of patient has these hormone levels?
Low TH(T3,4), TRH and TSH
Hypothalamic/anterior pituitary failure
What is the primary driver for goitre?
The activation of the TSH receptor by TSH or TSI auto-antibody
What function does iodinase serve?
Recycling of MIT and DIT for reuse in colloid cells
What are the compounds involved in the synthesis of TH?
Thyroglobulin, Tyrosine, Iodine
Describe iodination
In the follicular cells, iodide is converted back to active iodide by membrane bound thyroperoxidase
Describe iodine trapping
Iodine from diet is absorbed and reduced to iodide. Iodide from blood moves into follicular cells against [ ] grad through the Na+ - K+ pump, requiring ATP
What type of patient has these hormone levels?
High TSI, TH (T3,4) and Low TSH
Graves’ disease
What kind of hormonal profile does a patient lacking iodine have?
Low TH(T3,4) and High TSH
What are the steps in TH synthesis?
Tg synthesis. Tg and tyrosine attachment. Iodine trapping. Iodination. Coupling. Colloid resorption. Thyroglobin proteolysis.
What kind of hormonal profile does a patient with excess hypothalamic/anterior pituitary secretion?
High TH (T3,4), TRH and/or TSH
What are the effects of TH
Regulate BMR. Sympathomimetic, more susceptible to catecholamines. CV, increased HR, CO. Normal bone growth and maturation. Normal nervous sys development.
What type of patient has these hormone levels?
High TH (T3,T4) and Low TSH
Hyperthyroidism from hypersecreting tumour
What kind of hormonal profile does a patient with primary failure of thyroid gland have?
Low TH(T3,4), High TSH
Which enzyme converts T4 to T3?
5-deiodinase
What are the 2 stores of TH?
Colloid and Plasma proteins
