Flashcards in Lecture 17 - Thyroid Deck (19):
Normal functions of the thyroid?
normal growth & development, metabolic and oxygen, lipid and carbohydrate metabolism (body weight)
Embryology of thyroid?
endoderm origin, in thyroglossal duct, functional 12 weeks, independent 20 weeks,
Surroundings of thyroid?
recurrent pharyngeal nerves (posterior), oesophagus (to the left), superior and inferior thyroid artery, deep to sterno-hyoid muscle
150 microg/day, from salt, fish and bread, or supplements (pregnancy), deficiency leads to thyroid enlargement (Goitre)
Locations of Sodium-Iodide symporter?
thyroid, breast, gastric mucosa, salivary glands, cancer thyroid cells
Rare thyrotoxicity from overdose of thyroid supplements?
calcitonin, linked to medullary thyroid cancer
measured in hyper and hypothyroid, enzyme involved in T3 and 4 production
T4 and 3 bind to?
tissue receptors with alpha (LH, FSH, TSH and HCG) and beta subunits
in pregnancy, partial stimulation of TSH receptros which leads to a normal decline in TSH, and a rise in T3 and 4
Iodide and TSH?
TSH stimulates increases iodide in follicular lumen, increasing endocytosis to form T4, which converts to T3 in periphery; also increases blood flow, Tg, TPO and pyroxide
Regulation of thyroid hormone?
TRH, TSH and T3 negatively feedback in pituitary
Thyrotoxicosis/hyperthyroid - symptoms?
nervousness, weight loss, heat sensitive, tachycardia, weakness
Thyrotoxicosis/hyperthyroid - signs?
Goitre, skin changes, tremor, eye inflammation (glycans infiltrating fat)
autoimmune production of antibody that stimulates TSH receptor
Hyper-functioning regions of thyroid gland, not suppressed by circulating thyroid hormone
weight gain, cold, hair loss, constipation, oedema