Week 4: Thyroid Hormones

thyroid hormone synthesis

uptake of iodine, converts to iodine in GI, incorporate into tyrosine in protein thyroglobulin, undergos proteolysis to release t3/t4

thyroid gland stores thyroid hormone as

thyroglobulin

2 main ways that thyroid hormones are regulated

negative feedback loop, hypothalamus-pituitary axis

3 ways hypothalamus pituitary axis works on regulating thyroid hormone

TRH from hypothalamus, TSH from ant pit, TSH travels to thyroid to trigger t3 t4

physiological effects of thyroid

regulates metabolism of tissues, thermogenesis, growth and development, cardio effects, metabolic effects

thermogenesis

t3 and t4 increased BMR and heat production

growth and development is via

GH release, enhance gh on peripheral tissues, without t3/4 theres severe growth restriction

cardiovascular effects

increase HR and myocardial contraction

metabolic effects

increase availability of glucose and lips for cellular activity

hyperthyroidism symptoms

nervousness/tremor, weight loss, diarrhea, tachycardia, insomnia, increased apetite, heat intolerance, muscle wasting, goiter, exopthalmous

hypothyroidism symptoms

lethargy, weight gain, constipation, bradycarida, sleepy, anorexia, cold intolerance, weakness, dry skin, facial edema, can lead to short/mental retardation in kids

hypothyroidism causes

iodine deficiency, hashimoto thyroiditis, idiopathic

drugs to treat hypothyroidism

levothyroxine (Synthroid)

adverse effects of drugs for hypothyroidism

overdose of it leading to hyperthyroidism

maint treatments of hyperthyroidism

surgery or radioactive iodine to destroy gland. in both it makes it not function anymore and they go to hypothyroidism and need replacement therapy